International Journal of Food Engineering via MedWorm.com

Sucrose-Template Synthesis of Mesoporous Alumina from Aqueous Systems

International Journal of Food Engineering — Fri, 19 Mar 2010 23:10:21 +0100

Mesoporous alumina was prepared by using sucrose as a structure-directing template in an aqueous system. The resultant samples were characterized by using different methods such as x-ray diffraction, transmission electron microscopy, nitrogen adsorption-desorption analysis, and thermogravimetric and differential thermal analyses. The results showed that the prepared mesoporous gamma alumina has high surface area, uniform pore size distribution and excellent thermal stability. (Source: International Journal of Food Engineering)

Milled Rice Quality Assessment

International Journal of Food Engineering — Thu, 18 Mar 2010 22:38:51 +0100

Milling, an important processing step of rough rice, is usually done to produce white, polished grains. In this paper the quality of 22 milled rice varieties, common in Mazandaran, Iran, are investigated. These rice varieties included local varieties and breeding lines. Parameters assessed were head rice yield, degree of milling, husk removed percent, and total milling recovery. Results obtained revealed that the Tarom Mahali and Champa varieties have the highest head rice yield as 60.58 and 66.39 % and total milling recovery as 69.96 and 71.38 %, respectively. The greatest degree of milling value was found for the Haraz variety with a mean of 16.06 %. Also, it was found that the husk removed percent values were not statistically different among the varieties studied. Finally, considering ...

Retention of Volatile Constituents in Dried Toona sinensis by GC-MS Analysis

International Journal of Food Engineering — Thu, 18 Mar 2010 14:04:44 +0100

Toona sinensis, whose young leaves and shoots are edible and nutritious, is a perennial deciduous tree vegetable. In this paper, the volatile constituents of dehydrated fresh young leaves of Toona sinensis obtained by different drying methods were micro-extracted in solid-phase, and then analyzed with gas chromatography-mass spectrometry (GC-MS). The major flavor components include caryophyllene, aromadendrene, nonadecane, and phytol. Comparing with convection oven drying and natural solar drying, vacuum drying and microwave drying can preserve most of the original flavors of Toona sinensis. (Source: International Journal of Food Engineering)

Experimental Study on Energy Saving of Fluidized Bed Dryer with Self-Excited Mode Oscillating-Flow Heat Pipe Heat Exchanger

International Journal of Food Engineering — Thu, 18 Mar 2010 14:00:01 +0100

This paper investigated experimentally the influences of gas flow type, position of heat source and gas flow rate on the properties of a heat exchanger with a Self-Excited Mode Oscillating-Flow Heat Pipe (SEMOFHP). The SEMOFHPs were made from copper with an inner diameter of 3mm. Distilled water was used as working liquid. The results showed that the heat exchange capability of the SEMOFHP heat exchanger is about 3 times higher than that of a common tube heat exchanger. The heat exchanger unit used in the experiments was operated under counterflow, bottom heat source and high gas flow rate conditions. However, it was found that the unit could also work well with a top heat source arrangement. The heat recovery efficiency of the heat exchanger is slightly increased with the increase of inle...

Preparation of Redispersible Emulsion Powder by Spray Drying

International Journal of Food Engineering — Wed, 10 Mar 2010 02:01:44 +0100

There is a large demand for redispersible emulsion powder in various industrial applications because of its unique features. However, the use of this novel material is hindered by the complex synthesis processing technology and consequently high cost. In this paper, a simple preparation method for building material used redispersable emulsion powder is proposed. This method mainly includes two steps, a core-shell emulsion polymerization reaction and a following spray drying. In the emulsion polymerization step, AVE and MMA were used as seed emulsion and shell monomer for the core-shell polymeric structure. The influences of various factors such as monomer ratio, emulsifier and initiator as well as the feed method on particle configuration of core-shell structure polymeric emulsion were inv...

Microencapsulation of Gram-Negative Bacteria by Spray Drying

International Journal of Food Engineering — Wed, 10 Mar 2010 02:01:42 +0100

This paper presents an experimental study on the preparation of gram-negative bacteria microcapsules by spray drying. Effects of operating conditions on the bacteria survival rate were examined by single factor analysis. Through orthogonal experiment, appropriate conditions were determined as 160°C of the inlet air temperature, 12.5 ml/min of the feed flow rate, 1:9 of the ratio between gum arabic and maltodextrin, and 50 ml of fluid nutrient medium with the bacteria. The bacteria survival rate reaches 84.57% associated with above conditions. Examination of storage performance shows that after preserving in plastic film bag for 6 months under ambient temperature from 18°C to 30°C, quantity of the viable gram-negative bacteria was increased by 148%, which was significantly improved compa...

Comparison of Microwave Drying of Soybean in Static and Rotary Conditions

International Journal of Food Engineering — Wed, 10 Mar 2010 02:01:39 +0100

A rotary device was built in a home microwave oven, where wet soybean was dried in a dynamic moving state to improve the microwave drying uniformity. Experiments were conducted to investigate the relative water removal ratio which was defined to characterize the electromagnetic field distribution in microwave oven, and to compare the drying characteristics between static and rotary microwave drying. It is concluded that the kernel cracking ratio is lower when microwave drying of soybean was carried out in rotary state. Higher unit microwave power input results in rapid removal of water from soybean but an increase of kernel cracking ratio. (Source: International Journal of Food Engineering)

Experiments on Enhanced Heat Transfer of Self-Exciting Mode Oscillating-Flow Heat Pipe with Non-Uniform Structure

International Journal of Food Engineering — Wed, 10 Mar 2010 02:01:35 +0100

Experiments were performed on a closed loop self-exciting mode oscillating flow heat pipe (SEMOS HP) with uniform and non-uniform structures under the same tested conditions. The heat transfer characteristics are analyzed by comparing the temperature of wall of the heat pipe and output power when the heat input of the electric heating board and heating position are changed. The result shows that the heat transfer rate could be improved by using a non-uniform structure under low or middle heat input, and it gives the highest heat transfer performance when the non-uniform diameter section is at the bottom of the heat pipe and the heating source located below the non-uniform section. (Source: International Journal of Food Engineering)

Numerical Simulation of Oscillating Heat Pipe Heat Exchanger

International Journal of Food Engineering — Thu, 04 Mar 2010 20:20:54 +0100

Oscillating heat pipe is a new type high efficiency heat-transfer element. Its development and design attract increasing attention. This paper describes a numerical simulation for investigating on the flow and heat exchange performance of an oscillating heat pipe heat exchanger. The influences of the arrangement of heat pipe, the inlet temperature and the flux of hot air were explored. The results show that the heat exchange of staggered arrangement is more efficient than the aligned one. The influence of temperature difference on the heat exchanger by hot air flux is more than hot air inlet temperature. (Source: International Journal of Food Engineering)

Volatile Composition Changes of Pineapple during Drying in Modified and Controlled Atmosphere

International Journal of Food Engineering — Wed, 03 Mar 2010 22:13:22 +0100

Pineapple samples were dried in normal and modified atmospheres by addition of 0.5% ethanol v/v to the air stream using two different temperatures and two different velocities. The volatile composition changes during the drying process were determined using the solid phase microextraction coupled to a gas chromatographer with mass spectrometer. The modification of the drying atmosphere with ethanol vapor promoted a more intense water evaporation as well as a less pronounced loss of volatiles. The volatile composition changed significantly during drying not only by the loss of some components but also by the appearance of others. (Source: International Journal of Food Engineering)

A Scaling-up Approach from Experimental Tunnel to Spray Dryer

International Journal of Food Engineering — Tue, 02 Mar 2010 11:11:14 +0100

A scaling-up approach from drying of a thin layer wet material in a experimental tunnel to a pilot scale spray drying was developed through determining drying kinetics of quick evaporation process. Maltodextin was selected as solid material in solution to be dried. Critical moisture contents as a function of initial water evaporation rate (drying rate) shows that there is the same variation between the small scale test tunnel and the pilot scale spray dryer. Result of CFD modelling demonstrates that drying kinetics obtained from the small-scale tunnel could be properly applied to scale-up the spray drying process. (Source: International Journal of Food Engineering)

Analytic Solution of Mass Conservation Equation for Drying Process

International Journal of Food Engineering — Tue, 02 Mar 2010 11:11:11 +0100

Deep-bed drying is an integrated process affected by many different factors. In this regard, the nature of deep-bed drying phenomenon was discussed, and the models and mass equilibrium equations for deep-bed hot-air drying process were constructed for the study. The material dehydration process, medium humidification process and system equilibrium were analyzed. The dimensionless numbers were introduced to simplify and solve the differential equations of deep-layer drying. Furthermore, the analytical formula and solution of the deep layer hot-air drying process were given. The results provided a kind of simple and practical analytical formula and calculation method, which are the base to hold the characteristics of deep-layer drying system well, and realize the accurate control of process....

Numerical Evaluation of the Non-Isothermal Method for Determination of Moisture Diffusivity

International Journal of Food Engineering — Tue, 02 Mar 2010 11:11:07 +0100

A non-isothermal (linearly increasing temperature) procedure was used to determine the moisture diffusivity in mass transfer as a function of temperature with the complex optimization method. The effects of heating rate and experimental errors on the prediction accuracy of the parameters in Arrhenius equation were evaluated through pseudo-experimental data randomly generated on the basis of simulation results. An optimum heating rate of 0.01 K/s was found at which the experimental error less than 15% has negligible effect on calculated liquid diffusivity. (Source: International Journal of Food Engineering)

Thermal Analysis of Meat Emulsion Cooking Process by Computer Simulation and Experimental Measurement

International Journal of Food Engineering — Mon, 01 Mar 2010 23:09:48 +0100

The Finite Element Method was used to calculate the heat transfer processes that take place during cooking of meat emulsions formulated with different amounts of pork fat or olive oil. Experimental data acquired in the pilot plant were used to validate the theoretical model obtained by computer simulation. The results indicate that the computer simulation predicts to a good approximation. The most important parameters were cooking time and temperature of the meat emulsions. In addition, the theoretical model provides information about the temperature fields for all points in the meat emulsion. For a given fat content, no differences were found in the thermal properties of the emulsions elaborated with pork back fat or olive oil (p >0.05). Instead, the different fat and water content of the...

Air Drying Characteristics of Chili Pepper

International Journal of Food Engineering — Wed, 24 Feb 2010 00:43:32 +0100

The effect of pretreatments (water and steam blanching and by soaking in osmotic solutions of 60 and 70° brix) on drying behaviour of chili pepper dried at 60°C were investigated. During the experiments, the chili pepper was dried until there was no more water loss. The pre-treatment affected the course and rate of drying since the pretreated pepper dried faster than the untreated pepper and hence had a higher drying rate. The drying of the pepper occurred in the falling rate drying period. Four mathematical models were studied for the description of thin layer drying characteristics of the chili pepper. The models considered were the Newton, Henderson and Pabis, Logarithmic and Page model. Comparing the correlation coefficients (R2), chi-square (χ2), mean bias error (MBE) and root mean...

Enhancement and Scale-Up of β-(1, 3) Glucan Production by Agrobacterium sp.

International Journal of Food Engineering — Thu, 18 Feb 2010 02:47:48 +0100

Curdlan is a water insoluble polysaccharide composed exclusively of β-(1, 3) linked glucose residues. Agrobacterium sp. is known to produce extracellular curdlan under nitrogen-limited conditions. The purpose of this study was to investigate the effects of pH, amounts of ammonium, sucrose and trace elements, and time the addition of sucrose, ammonium and uracil on the production of curdlan in a shake flask and to further scale-up the process to a 5 L fermentor. A maximum of 48.7 g L-1 of curdlan was obtained in a shake flask when 150 and 1.4 g L-1 of sucrose and ammonium were used at the initial pH of 6.5. The production was enhanced to 57 g L-1 by adding one third of sucrose and 1 g L-1 of uracil at the 48th h in a fed batch mode. The process was scaled up to a 5 L bioreactor in a batch ...

A Comparative Study of Physicochemical and Rheological Properties of Iranian Tomato Pastes

International Journal of Food Engineering — Wed, 17 Feb 2010 02:53:55 +0100

In this study, the physicochemical properties and rheological behavior of a number of tomato pastes manufactured by Iranian food processors were compared. Chemical composition tests, color measurement, consistency and rotational viscometry were performed. There were significant differences among the samples in terms of Brix, salt level, vitamin C and Hunter color parameters (L and a/b). Some of the parameters did not pass the standard requirements set by the Institute of Standards and Industrial Research of Iran (ISIRI), e.g. Brix, color and salt. The rotational viscometry tests and shear stress-shear rate curves at 30, 45 and 60°C indicated the existence of variations among the samples in terms of apparent viscosity and yield stress. All tomato paste samples in this study were non-Newton...

Optimization of Osmotic Dehydration Process of Aonla Fruit in Salt Solution

International Journal of Food Engineering — Wed, 10 Feb 2010 01:49:16 +0100

For optimization of osmotic dehydration process of aonla fruit in salt solution by response surface methodology, the experiments were conducted according to Box and Behnken design. The independent process variables for osmotic dehydration process were osmotic solution concentrations (5-25% w/v salt), osmotic solution temperature (30-60°C), solution to fruit ratio (4-8 v/w), and process time (60-240 minutes). The osmotic drying process was optimized for maximum water loss, overall acceptability and minimum solute gain, colour change, and vitamin-C loss. The optimum conditions were 22% salt concentration, 44.5°C osmotic solution temperature, 6.5 solution to fruit ratio, and 60 minutes process time. An analysis of variance (ANOVA) revealed that, among the process variable, concentration has...

Effect of Drying Temperature and Soaking Conditions on Wet-Milling Characteristics of Amaranth Grain

International Journal of Food Engineering — Wed, 27 Jan 2010 02:32:26 +0100

Amaranth grains (Amaranthus cruentus) were air-dried at 40, 70 and 100 ºC and a moisture range from 29.5 to 10.2, dry basis (d.b.). Dried grains were wet-milled at 53.9ºC in the presence of SO2 aqueous solution in order to obtain fractions of starch, protein and fiber. Effect of drying temperature and SO2 concentration (0.01 - 0.05 w/v %) on fraction yields and protein content of starch were investigated using response surface method (RSM). A factorial design including triplicate of central point was performed. Starch and protein yields decreased as drying temperature increased while fiber yield and protein content in starch fraction shown the opposite behaviour. Protein yield and protein in starch fraction were affected negatively by SO2 concentration. Interaction among studied factors ...

Role of Cryogenics in Food Processing and Preservation

International Journal of Food Engineering — Wed, 13 Jan 2010 09:32:11 +0100

Food materials are perishable by nature. They require processing or preservation techniques to enhance the storage life. Cryogenics is a branch of engineering wherein production of cryogen and the maintenance of low temperature technologies are studied. One such cryogen, liquid nitrogen (LN2) has a tremendous potential to be used as a total loss refrigerant. In this paper, the different aspects of the utilization of LN2 as a refrigerant and as a gas are discussed in details. In freezing for individual quick freezing LN2 can be used as a refrigerant to get an ultra rapid freezing. Due to its rapidity LN2 freezing is capable of producing small ice crystals in size and there by helps immensely in retaining quality reducing substantial amount of drip loss. LN2 has gained tremendous popularity ...

Effective Conditions for Extracting Higher Quality Kernels from the Sonnati salams Apricot

International Journal of Food Engineering — Wed, 13 Jan 2010 09:32:07 +0100

This study focused on researching the effective conditions for extracting high quality apricot kernels. Specifically, we analyze the effects of moisture content and compression axis on the amount of force needed to crack apricot pits and kernels. Apricot pits were analyzed at 6.82, 12.93, 17.81 and 23.01% wet base moisture contents and apricot kernels were analyzed at 2.86, 4.10, 8.81 and 13.03% wet base moisture contents. Apricot pits and kernels were compressed at different moisture contents and the amounts of needed force for cracking were calculated along the length, width and thickness of pits and kernels. It was observed that, with increasing moisture content of the apricot pits and kernels, the energy for cracking decreased. Furthermore, this study also revealed that cracking an apr...

Color Based Identification and Classification of Boiled Food Grain Images

International Journal of Food Engineering — Wed, 30 Dec 2009 01:14:52 +0100

Texture and color are the important features used in identifying objects or regions of interest (ROI) in any image, be it a photomicrograph, an aerial photograph, or a satellite image. We propose a methodology for identification and classification of boiled food grains based on the level of boiling using two color models HSV and L*a*b*, in Indian context. These color models provide good texture definition for any image. The classification is performed at two levels: Level 1 determines the type of grain image and Level 2 estimates the amount of boiling, as full boiled, medium boiled and half boiled. Results show average accuracies of 80% and 96% for first level and 70% and 96% accuracies for second level classifications for HSV and L*a*b*, respectively. The work is applicable to automatic i...

Selective Adsorption of Vitamin E from Palm Fatty Acid Distillate on Silica-Packed Fixed-Bed Columns

International Journal of Food Engineering — Wed, 30 Dec 2009 01:14:49 +0100

In this study, a pre-concentrated vitamin E fraction from palm fatty acid distillate (PFAD) was subjected to a normal phase silica-packed fixed-bed column for further purification. The effect of various operational parameters i.e. column bed height, vitamin E inlet concentration, column temperature and flow rate on column performance were detailed. It appeared that the breakthrough curves of all systems showed a typical S-shaped profile. The service time of the column increased when increasing the column bed height, or reducing the inlet concentration, column temperature and flow rate. It was found that column efficiency in terms of adsorbent usage rate could be improved by decreasing the inlet concentration and flow rate. Decreasing the column temperature resulted in higher column capacit...

Effects of Different Pretreatments on Drying Kinetics and Quality of Sweet Potato Bars Undergoing Air Impingement Drying

International Journal of Food Engineering — Wed, 23 Dec 2009 04:53:45 +0100

The effects of hot water blanching (HWB), superheated steam blanching (SSB) and citric acid pretreatment (CAP) on drying kinetics and quality of sweet potato bars undergoing air impingement drying were examined in this investigation. It was found that CAP could significantly improve the drying rate of the samples, whereas HWB and SSB could obviously decrease the drying rate. In terms of quality, hardness, microstructure and color of the dried sweet potato bars subjected to different pretreatments were studied. Results illustrated that the pretreatments had significant effects on the texture, microstructure and color of the samples. Considering the drying kinetics and quality attributes, SSB is more suitable than HWB and CAP pretreatment for drying sweet potato. (Source: International Journ...

Physical Properties of Rough Rice

International Journal of Food Engineering — Tue, 08 Dec 2009 01:32:56 +0100

Knowledge of the physical and mechanical properties of the rice grain is being used in the handling, planting, harvesting, threshing, cleaning, size grading, up grading, treating and packaging. Several physical properties of three rough rice cultivars (Poya, Khazar and Haraz) were determined and compared in terms of length, width, thickness, aspect ratio, arithmetic diameter, geometric diameter, equivalent diameter, sphericity, mass, volume, surface area, bulk density, true density and porosity. A linear model for describing the mass of rough rice grain for each cultivar was also investigated. (Source: International Journal of Food Engineering)

Vapour Transport Mechanism in Osmotic Distillation Process

International Journal of Food Engineering — Fri, 20 Nov 2009 22:17:08 +0100

Osmotic distillation experiments were carried out using pure water as feed in order to investigate the mass transfer mechanism in the membrane. In the experiment, the hollow fibre modules with packing density of 30.6 and 61.2% were employed. The Dusty gas model was used to estimate the transport of vapour through the membrane. The results revealed that the water vapour transport in the membrane pores in this study followed the Knudsen-molecular diffusion transition model. The value of membrane mass transfer coefficient evaluated by the transition model was found to be 0.863 kg/m2.h.Pa which was in good agreement with the experimental value. The packing density of the module did not affect the membrane mass transfer coefficient. On the other hand, the membrane mass transfer coefficient depe...

Rapid Detection Techniques for Biological and Chemical Contamination in Food: A Review

International Journal of Food Engineering — Thu, 12 Nov 2009 21:03:13 +0100

This article overviews the progress of the rapid detection methods for biological and chemical contamination in food. (Source: International Journal of Food Engineering)

Use of Cassava Peel as Carbon Source for Production of Amylolytic Enzymes by Aspergillus niveus

International Journal of Food Engineering — Tue, 03 Nov 2009 22:26:11 +0100

Aspergillus niveus produced high levels of α-amylase and glucoamylase in submerged fermentation using the agricultural residue cassava peel as a carbon source. In static conditions, the amylase production was substantially greater than in the agitated condition. The optimized culture conditions were initially at pH 5.0, 35°C during 48 hours. Amylolytic activity was still improved (50%) with a mixture of cassava peel and soluble starch in the proportion 1:1 (w/w). The crude extract exhibited temperature and pH optima approximately 70°C and 4.5, respectively. Amylase activity was stable for 1 h at 60°C, and at pH values between 3.0 and 7.0. The enzyme hydrolysed preferentially maltose, starch, penetrose, amylose, isomaltose, maltotriose, glycogen and amylopectin, and not hydrolysed cyclo...

Recognition and Classification of Food Grains, Fruits and Flowers Using Machine Vision

International Journal of Food Engineering — Thu, 29 Oct 2009 02:58:30 +0100

In this paper, we have presented different methodologies devised for recognition and classification of images of agricultural/horticultural produce. A classifier based on BPNN is developed which uses the color, texture and morphological features to recognize and classify the different agricultural/horticultural produce. Even though these features have given different accuracies in isolation for varieties of food grains, mangoes and jasmine flowers, the combination of features proved to be very effective. The average recognition and classification accuracies using colour features are 87.5%, 78.4% and 75.7% for food grains, mango and jasmine flowers, respectively, and the average accuracies have increased to 90.8%, 80.2% and 85.8% for food grains, mangoes and jasmine flowers ,respectively, u...

Modeling and Optimization of the Sugar Extraction Process

International Journal of Food Engineering — Thu, 08 Oct 2009 06:25:17 +0100

This study determines these optimal values in a way to minimize the total operating costs based on the mathematical model using the genetic algorithm method. The results of this study can be used as a framework to optimize the performance of industrial extractors. (Source: International Journal of Food Engineering)

Production of Shelf-Stable Annurca Apple Juice with Pulp by High Pressure Homogenization

International Journal of Food Engineering — Wed, 07 Oct 2009 00:43:37 +0100

Annurca apple juice was processed by high pressure homogenization (HPH) to inactivate the endogenous microbial flora, with the aim of maintaining the organoleptic properties and the polyphenolic content of the fresh juice. In particular, it was shown that the shelf life of clear juice can be prolonged for many weeks of storage both at 4°C and 37°C upon HPH treatment at 250 MPa. Instead, the juice with pulp required higher pressure levels (300 MPa) for microbial stabilization both at 4°C and 37°C. The sample stored at 37°C exhibited a physical instability, with deviation in color and pH, which reduced the shelf life, but the samples stored at 4°C exhibited an excellent microbial stability and no observable variation of pH and color, suggesting that HPH can represent a good option for ...

3-D Imaging of Deep-Fat Fried Chicken Nuggets Breading Coating Using X-Ray Micro-CT

International Journal of Food Engineering — Tue, 22 Sep 2009 12:38:55 +0100

Food coatings are used to add value to deep-fat fried foods and to control heat and mass transfer during frying. They impart special characteristics such as crispiness and flavor to fried products while they also form a barrier to moisture and fat transfer during frying. Development of structure during frying plays an important role in defining the performance of batter/bread coatings. Food structural properties such as porosity have been associated with fat uptake in fried foods. A good understanding of the microstructural properties is necessary in order to produce high quality fried foods. X-ray micro-computed tomography (X-ray micro-CT) is a unique technique for imaging food non-invasively, requiring no or minimal sample preparation and 3-D rendition of high resolution images. The tech...

Effects of Flaxseed Gum Addition and Drying Conditions on Creep-Recovery Properties and Water Vapour Transmission Rate of Starch-Based Films

International Journal of Food Engineering — Tue, 22 Sep 2009 12:38:51 +0100

This study investigated the effect of different concentrations of flaxseed gum (0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%) and various drying conditions (40 °C, 60 °C, 80 °C) on creep-recovery property and water vapor transmission rate (WVTR) of a starch-based films composed of cornstarch, flaxseed gum and glycerol. In creep-recovery tests, the data were modeled by Berger model. Results showed that E2 and η1 of different flaxseed gum concentrations all decreased with an increase of flaxseed gum concentration first and then increased in both creep and recovery tests. Increasing drying temperature decreased E2 and η1 in both creep and recovery tests. The addition of flaxseed gum increased WVTR compared with the flaxseed gum free sample. Films under different drying conditions displayed similar W...

Model of Steam and Water Extraction of Essential Oil of Eucalyptus Citriodora Using a Complete 2n Factorial Plan

International Journal of Food Engineering — Tue, 08 Sep 2009 23:32:04 +0100

The steam and water distillation of leaves of Eucalyptus citriodora was modeled using a complete 2n factorial plan. Eight experiments were carried out, with three easily interpretable variables, for steam distillation and for a first degree polynomial model. The average essential oil yield was 2.3%. Positive effects decreased in the order: duration of the extraction, heating power and state of division of the plant. Interactions were negligible. Extraction conditions had no practical impact on citronellal content, which yielded an average content of 83.26% with a range of 80.2-85.4%. Weak negative effects were observed on duration of heating and state of division of plant material. Sixteen experiments were conducted on four variables for water distillation. The extracted essential oil yiel...

Pulsed Infrared Roasting of Groundnuts and its Quality

International Journal of Food Engineering — Thu, 27 Aug 2009 00:46:08 +0100

The application of high intensity, pulsed infrared radiation for roasting of groundnuts is attempted and the product quality is compared with that of the conventionally roasted samples. Product qualities such as lightness (color), compressive strength (texture) and free fatty acid content are analyzed for different combinations of roasting duration (4-12 min) and temperature (160-200°C), selected based on central composite rotatable design (CCRD). Pulsed infrared roasting at 178-188°C for 6.8-9.2 min resulted in optimum product quality in terms of color, texture and free fatty acid content. The other parameters such as oil and moisture content, peroxide value and sensory characteristics of roasted nuts are also evaluated for the select temperature-duration combinations. The oil yield inc...

Respiration Rate Models of Agaricus bisporus under Modified Atmosphere Packaging

International Journal of Food Engineering — Mon, 24 Aug 2009 21:48:16 +0100

The package headspace composition, in terms of O2 and CO2 concentrations, in modified atmosphere packaging (MAP) of Agaricus bisporus at 2, 4, 8 and 20°C were respectively monitored within 15h by a gas chromatograph. The respiration rate of Agaricus bisporus under modified atmosphere packaging at any instant of time were calculated by a C program based on permeable system. The dependence of respiration rate on gas composition was well described by a Michaelis-Menten type enzyme kinetic equation with uncompetitive CO2 inhibition. The model parameters were estimated by fitting the model to the experimental data by non-linear regression using Excel. The relationship between maximum rate Vm and temperature was well described by the Arrhenius equation. The results suggest that, the respiration...

Evaluation of Methodologies for Mathematical Modeling of Packaged Conductive Foods Heat Process

International Journal of Food Engineering — Mon, 24 Aug 2009 21:48:06 +0100

The heat process is a safe method of food preservation. The use of mathematical modeling for heat transfer by finite elements analysis (FEA) makes it possible to determine the cold spot of conventional and non conventional packages, evaluate their thermal history, microbial and enzyme inactivation and nutrients retention for an optimum process design. Several works use simplifications during mathematical modeling, such as adiabatic headspace, considering the thermal resistance of package negligible. The impact of these simplifications is rarely evaluated. The aim of the present work was to evaluate the effect of these simplifications on sterilization value (Fp) for a conductive food. Two commercial glass bottles (G1 and G2) were selected for the assays. FEA model was built using the bottle...

Particle Size Distribution of Commercial Cowpea (Vigna unguiculata (L) Walp.) Flour and Sensory Properties of Akara

International Journal of Food Engineering — Thu, 20 Aug 2009 00:19:26 +0100

In this study, particle size distribution of commercially produced cowpea flour was determined and the sensory properties of akara made from it were compared with that prepared using a traditional method. The commercial cowpea flour notably had finer particles than the traditional paste. Over 40% of the commercial cowpea flour had particles finer than 0.75x10-4m as against 25% of the traditional paste. The concentration of particles intermediate between flour and grits (i.e. in the 2x10-4m - 6.0x10-4m pore region) was higher in the traditional paste (44.72%) than the commercial cowpea flour (18.36%). All the akara had high scores for colour, while the commercial cowpea flour akara had significantly (p≤0.05) lower scores for texture, flavour and overall acceptability. The commercial flour...

Comparative Experiment on Hot-Air and Microwave-Vacuum Drying and Puffing of Blue Honeysuckle Snack

International Journal of Food Engineering — Tue, 11 Aug 2009 23:39:51 +0100

A comparative drying experiment between the hot-air and microwave-vacuum method of blue honeysuckle slice has been completed. In hot-air drying, the temperature was 50°C when the velocity of air stream was kept at 0.5 m/s. In microwave-vacuum puffing, the microwave power and vacuum pressure were set at 2.68kW and 82 kPa, respectively. Comparing to the quality indexes viz. texture characteristics (hardness and crispness), color, cross-section structure and vitamin C content of blue honeysuckle snack, it was known that hardness of blue honeysuckle snack decreased by 3936g, crispness increased by 3, value of lightness, redness and yellowness increased by 2.09, 0.2, 0.27, respectively, and the retention rate of VC content increased by 9.67% using microwave-vacuum puffing than that using hot-a...

Moisture Isotherms and Heat of Desorption of Pistachio (Kaleghochi Var.)

International Journal of Food Engineering — Mon, 10 Aug 2009 21:27:04 +0100

Moisture desorption isotherms (EMC/ERH) of Iranian pistachio variety of Kaleghochi were determined at 45, 60, 75 and 90°C using the standard gravimetric static method over a range of relative humidity from 10% to 82%. The experimental desorption curves were fitted under the following different equations: modified Henderson, modified Chung-Pfost, modified Halsaey and modified Oswin. The modified Oswin model was found to be a suitable model for describing the desorption isotherms of pistachio. The net isosteric heat of desorption of pistachio was also determined from the equilibrium data at different temperatures. Furthermore, the net isosteric heat of desorption of pistachio varied between 13.2 - 2.2kJ/mol at moisture varying between 2.5 - 15% (d.b). (Source: International Journal of Food ...

Effects of Blanching Methods on Drying Kinetics of Oyster Mushroom

International Journal of Food Engineering — Sat, 08 Aug 2009 06:45:56 +0100

Oyster mushroom was treated with hot water and steam blanching prior to drying in cabinet dryer. A hot air cabinet dryer was used for drying mushroom at 40, 50, 60, 70 and 80°C temperatures. Solid loss was observed to be 25.46% and 3.32% (wb) during hot water and steam blanching, respectively. Highest drying rate was observed for hot water blanched mushroom followed by unblanched and steam blanched mushroom. This leads to more drying time for the steam blanched mushroom followed by the unblanched and hot water blanched mushroom for the same level of drying. The drying data was modeled for exponential and Page's drying model. Page's model was found to be better than the exponential model for the prediction of drying rate. The value of the model parameters of the exponential model was found...

Development of a Microcontrolled Instrument to Determinate Thermal Conductivity of Foods

International Journal of Food Engineering — Wed, 05 Aug 2009 23:45:39 +0100

This work was done to develop a device of easy utilization and low cost that is able to determine the thermal conductivity of foods. It is based on the utilization of the hot wire transient method. The device has a hypodermic needle. In this needle, a wire of Nickel-Chromium (that is responsible for the probe heating) and a thermistor (used to read the temperature) were inserted. The constructive system of the device is based on the use of a Basic Stamp microcontroller which controls all the analysis-related events, like temperature readings during the time, needle heating, solving equations involving the collected temperature data and showing the analysis results through a display of liquid crystal. So, the developed equipment does not need any kind of extra device to accomplish the analy...

Statistical Modelling of Gluten Production by Varying Mixing Time, Salt and Water Levels During Dough Mixing

International Journal of Food Engineering — Wed, 05 Aug 2009 23:27:48 +0100

Gluten is widely discussed in dough and breadmaking subjects but the focus has not been on the production of gluten itself for usage and application in the food industry. This paper presents some modelling studies of gluten production using response surface methodology (RSM) by varying three main factors that contribute towards gluten formation during dough mixing, which are the mixing time, salt and water levels. The gluten produced was measured for its quantity in terms of wet and dry gluten contents and for quality, in terms of volume expansion of fried gluten and extensibility of gluten. Two wheat flour types, the strong and weak were used as comparison. The experiment was designed following a standard RSM design, known as the central composite design. The results of analysis of varian...

Retention of Lysine in Foods Processed with Microwave and Conventional Heating

International Journal of Food Engineering — Wed, 05 Aug 2009 05:46:11 +0100

The effect of moist and dry heat processing on lysine content of selected foods was investigated. Two moist heat (open and closed vessel) and dry heat (microwave and hot air oven) methods were chosen for processing samples from cereal, oilseed and pulse groups with whey protein concentrate as reference sample. Unheated samples served as controls. The samples were analysed for protein content, available lysine by fluorodinitrobenzene method and for in vitro protein digestibility (IVPD). Results indicated that in moist heat-treated samples lysine retention was between 69 - 83%. Dry heat treatment resulted in a greater loss of lysine, which was proportional to the degree of heating. The retention of lysine in dry heat-treated samples ranged from 31 to 65 %. All heated samples had higher dige...

Production of Cellulolytic Enzymes by Anaerobic Fungi Cultivated in Different Conditions

International Journal of Food Engineering — Tue, 04 Aug 2009 22:10:50 +0100

The present paper studies the influence of different nutrients for the production of two cellulolytic enzymes: endo beta-1.4 glucanase and exo beta- 1.4 glucanase by anaerobic fungi taken from cow rumen, that were fed a diet of corn silage and Brachiaria decumbens grass hay. During the enzymatic degradation assays, it was observed that the addition of some essential nutrients in the formulation of the culture medium contributed positively in the cellulolytic enzyme production, with exception of riboflavin. Such results contributed in the establishment of an effective method for the evaluation of enzymatic activities in anaerobic fibrolytic fungi. In this work, nutrients added to enrich the culture medium have successfully proven that they can be used as inoculating agents (inductors) in di...

Study of the Rheological Parameters of Honey Using the Mitschka Method

International Journal of Food Engineering — Tue, 04 Aug 2009 22:10:46 +0100

In this work the rheological behavior of two varieties of honey were evaluated using a Brookfield viscometer R.V.T in a temperature range of 5-20°C. In order to interpret the experimental results in terms of viscosity, the torque-speed data and scale readings were converted into shear stress-shear rate relations using numerical conversion values proposed by Mitschka. This method offers excellent potential for quality control testing in the food industry. Samples exhibited Newtonian behavior and the temperature effect on the viscosity followed an Arrhenius-type relationship. (Source: International Journal of Food Engineering)

Investigation on Acid Hydrolysis of Inulin: A Response Surface Methodology Approach

International Journal of Food Engineering — Tue, 04 Aug 2009 22:10:42 +0100

In this study, the acid hydrolysis of inulin was investigated as a function of three variables: pH, temperature and time. Inulin hydrolysis was detected by measurement of reducing sugars, using Dinitro Salicylic acid (DNS) method. The central composite rotatable design (CCRD) was applied to design an experimental program to model the effects of acidic and alkaline pH on the inulin hydrolysis. Additionally, response surface methodology (RSM) was utilized for data analysis. The statistical analysis of the results confirmed that pH, temperature and time are significant variables at acidic pH, whereas at alkaline pH, these variables are insignificant. The maximum amount of inulin hydrolysis obtained at the pH < 2, temperature > 90°C and the time of 1 hrs. (Source: International Journal of Foo...

Modeling of the Soybean Grains Hydration by a Distributed Parameters Approach

International Journal of Food Engineering — Mon, 03 Aug 2009 23:43:44 +0100

A mathematical model with distributed parameters was proposed to describe the absorption of water by soybeans, in order to evaluate the moisture content variation with time inside the grains. This model was represented by a partial differential equation (second order relative to position and first order relative to time), whose parameters were numerically adjusted using a minimum squares method. For this purpose, available MATLAB® routines were used, together with experimental data obtained from hydration tests where soybeans were immersed in liquid water at temperatures of 10, 20, 30, 42 and 49°C. According to the results, the model was able to represent the main characteristics of the hydration process, with a maximum deviation of 10% in the whole set of experimental conditions. (Sourc...

Study on Creep Properties of Japonica Cooked Rice and Its Relationship with Rice Chemical Compositions and Sensory Evaluation

International Journal of Food Engineering — Mon, 03 Aug 2009 23:43:40 +0100

Creep properties of four varieties japonica cooked rice were tested using a dynamic mechanical analyzer (DMA Q800). The creep curve was described by Burgers model. The creep process of japonica cooked rice mainly consisted of retarded elastic deformation, εR and viscous flow deformation, εV, and negligible instantaneous elastic deformation, εE. The retarded elastic modulus, Ε2, relaxation time, τ, and the viscosity coefficient, η1, of the cooked rice according to the Burger model were estimated through nonlinear regression. The effect of the chemical compositions on the rheological parameters based on creep behavior of cooked rice was assessed. Correlation analysis indicated that the retarded elastic modulus, Ε2, had positive correlations with protein (r = 0.952, P = 0.048). The rel...

Drying Kinetics of Lima Bean (Phaseolus lunatus L.) Experimental Determination and Prediction by Diffusion Models

International Journal of Food Engineering — Sat, 01 Aug 2009 02:48:49 +0100

This article aims at determining thin-layer drying curves for grains of lima bean, variety olho-de-peixe and to predict them using diffusion models. Samples of lima bean (110.0 g) with initial moisture content of 66.0% (wet basis, wb) were dried at temperatures of 40.0, 50.0 and 60.0°C. The effective diffusivity of moisture was determined by analytical solutions of the mass diffusion equation (Fick's second law) with prescribed boundary condition for spherical, cylindrical, and infinite slab at each temperature. Comparison with the experimental data showed that the infinite slab with constant diffusivity predicted more accurately, but statistical indicators of the goodness of fit were not completely satisfactory. Thus, a model for the infinite slab with constant volume, moisture-dependent...

Development of a Sterilized Mixed Herbal Drink Product

International Journal of Food Engineering — Wed, 29 Jul 2009 00:40:08 +0100

A sterilized mixed herbal drink formula and process was developed for the mixed herbal extracts from Imperata cylindrical (L.) P. Beauv [IC], Murdannia loriformia (Hassk.) Rolla Rao et Kammathy [ML], Hedyotis corymbosa Lamk. [HC] and Orthosiphon aristatus Miq [OA]. Increasing extraction temperature and time decreased the antioxidant activity and increased the total potassium and phenolic compound contents of the herb infusions. Using response surface methodology (RSM), the appropriate extraction condition was 74.6°C for 41 minutes. The most acceptable formula contains a % weight ratio (w/w) of 14:35:27:17of IC: ML: HC: OA infusions to 7% (w/w) sucrose. Decreasing the sterilization temperature and increasing the F0-value reduced the antioxidant activity and total phenolic compounds. The ap...

Effect of Guar Gum on Dough Stickiness and Staling in Chapatti-An Indian Unleavened Flat Bread

International Journal of Food Engineering — Tue, 28 Jul 2009 21:19:36 +0100

Chapatti, Indian unleavened flat bread made of whole-wheat flour, is traditionally prepared in households by hand sheeting of dough followed by baking on hot griddle and is consumed fresh. Investigations were made to study the effect of guar gum on whole wheat chapatti dough stickiness and its effect on staling of chapatti during storage. Guar gum was incorporated at various levels ranging between 0.25-1.0% w/w of whole wheat flour. Chapatti dough was prepared and evaluated for dough stickiness using Chen-Hoseney dough stickiness probe. Chapattis were prepared and monitored for staling parameters such as water soluble starch (WSS), moisture content, in vitro enzyme digestibility (IVED), extensibility and tear force, both when fresh and after storage for three days at room temperature (30±...

Co-Production of Betacyanine and Eau-De-Vie from Red Beets (Beta vulgaris)

International Journal of Food Engineering — Mon, 27 Jul 2009 23:08:18 +0100

An improved process with commercial wine yeast Saccharomyces cerevisiae Montrachet was developed for co-production of betacyanine (a natural red beet pigment) and red beet eau-de-vie from the juice of red beet roots (Beta vulgaris). Red beet wines contained more than 55 g/L ethanol and approximately 0.95 g/L betacyanine. The samples of red beet eau-de-vie prepared by distillation of red beet wines had 180 g/L ethanol and the stillages contained nearly 2.5 g/L betacyanine. (Source: International Journal of Food Engineering)

Physicochemical and Functional Properties of Cultivars of Irish Potato and Cassava Starches

International Journal of Food Engineering — Mon, 27 Jul 2009 23:08:14 +0100

In this study, starches were extracted from two cultivars of local Irish potatos (Solanum tuberosum,) and tree cultivars of local Cassava (Manihot esculanta). These starches and a commercial Irish potato starch (IPS), where characterized with respect to their physico-chemical and functional properties. Significant differences (P (Source: International Journal of Food Engineering)

Optimization of Osmotic Dehydration of Radish in Salt Solution Using Response Surface Methodology

International Journal of Food Engineering — Thu, 23 Jul 2009 23:41:13 +0100

Response surface methodology was used to determine the optimum processing conditions that yield maximum water loss and weight reduction and minimum solid gain during osmotic dehydration of radish in salt solution. The experiments were conducted according to Central Composite Design (CCD). The independent process variables for osmotic dehydration process were temperature (25 - 45°C), processing time (30 -150 minutes), salt concentrations (5 - 25% w/w) and solution to sample ratio (5:1 - 25:1). The osmotic dehydration process was optimized for water loss, solid gain, and weight reduction. The optimum conditions were found to be: temperature - 36°C, immersion time - 95 min, salt concentration - 25% and solution to sample ratio 15:1. At this optimum point, water loss, solid gain and weight r...

Efficiency of Electrolyzed Oxidizing Water for Inactivation of Salmonella spp. and Inoculated Shell Eggs

International Journal of Food Engineering — Wed, 22 Jul 2009 22:24:11 +0100

The risk of a salmonellosis outbreak from consuming contaminated eggs is a societal and governmental concern. The bactericidal efficiency of electrolyzed oxidizing (EO) water for inactivation of salmonella and artificially inoculated shell eggs were evaluated in this study. The effects of available chlorine concentration (ACC, 0.1-2.0 mg/l) and pH value (2.3, 3.5, 4.6, 5.7 and 6.5) on the bactericidal activity of EO water were investigated by using pure cultures (7.0-8.0 log10 CFU/ml) of Salmonella pullorum and Salmonella enteritidis strains. EO water was effective for inactivation of both pathogens. The bactericidal activity increased with increasing the ACC of EO water. The bacteria were completely inactivated when the ACC of EO water was higher than 1.0 mg/l. At a sufficient ACC (greate...

Performance Evaluation of Absorbent Materials in Evaporative Cooling System for the Storage of Fruits and Vegetables

International Journal of Food Engineering — Tue, 21 Jul 2009 23:34:05 +0100

An experimental storage based on the principle of evaporative cooling was designed to evaluate the performance of three natural absorbent fiber materials to be used as cooling pads. The absorbent materials were jute, hessian and cotton waste. The performance criteria included cooling efficiency, material performance and total amount of heat load removed from the evaporative cooler. The results showed that under the no-load condition, the average cooling efficiency was highest for jute at 86.2%, compared to 76.3% for cotton waste and 61.7% for hessian fiber. Materials performance tests results showed that the highest resistance to mold formation was exhibited by hessian followed by cotton waste, while the jute fiber had very poor performance. The heat load determination also showed that pro...

Fractionation of Skim Milk by an Integrated Membrane Process for Yoghurt Elaboration and Lactose Recuperation

International Journal of Food Engineering — Mon, 20 Jul 2009 22:15:59 +0100

A combined membrane process has been used to fractionate skim milk. Microfiltration and ultrafiltration were employed to obtain concentrates with different protein/lactose ratios depending on the volume concentration ratio to produce protein enriched yoghurt. Nanofiltration has been used for lactose recovery from the ultrafiltration permeate with partial demineralization, while the permeate water of NF can be reused or recycled. Feed, permeate, concentrates and yoghurt have been physicochemical characterized and compared with commercial products. The obtained yoghurts have a smooth aroma and an agreeable taste, the protein content increased up to 50 % and the lactose content decreased approximately 50 % in comparison with commercial yoghurts, while calcium and iron were also increased, lea...

The Effect of Moisture Content on Colour Characteristics of Walnuts

International Journal of Food Engineering — Thu, 16 Jul 2009 23:35:03 +0100

The size, colour, level of internal damage and external damage of walnuts are four important quality factors. Colour properties ('L', 'a', 'b', hue angle and chroma values) of Bilecik, Yalova-1 and Yalova-3 shelled walnut varieties as a function of moisture content were determined. The average 'L' values of shelled walnuts decreased with increase in moisture content for Bilecik, Yalova-1 and Yalova-3 walnut varieties. All colour characteristics were affected by the moisture content studied. (Source: International Journal of Food Engineering)

Development of Image Based Modeling for Determination of Oil Content and Days Estimation for Harvesting of Fresh Fruit Bunches

International Journal of Food Engineering — Tue, 07 Jul 2009 00:52:20 +0100

In this study, the relationship of oil extraction rate (OER) and fruit ripeness will be determined. The sample of oil palm fruits was collected from the unripe until the overripe stage and the oil content of the mesocarp for fresh fruit bunches (FFB) was extracted by using bunch analysis procedure to get the oil extraction rate. Using the same samples of FFB, the pixel value of images which measure in hue, was determined by developed image analysis software. The images were captured under an outdoor environment in an oil palm plantation. The sunlight intensity of environment was recorded using Extech light meter at various times of the day from morning to afternoon in the oil palm plantation. The result of the experiment that showed a good relationship was found between the oil content of ...

Predictive Modeling of Salmonella Species Inactivation in Ground Pork and Turkey during Cooking

International Journal of Food Engineering — Tue, 07 Jul 2009 00:52:17 +0100

The objective of this study was to evaluate the ability of the Weibull distribution to predict the inactivation of Salmonella in three meat products cooked under isothermal and non-isothermal conditions. Ground turkey thigh (5.09% fat, pH 6.45), turkey breast (0.47% fat, pH 6.04) and pork (17.04% fat, pH 6.36) were inoculated with an 8 strain Salmonella cocktail. The meat was cooked isothermally at 50, 54, 58, 62 and 66ºC, and non-isothermally at two heating rates (5 or 10 ºC/min) to 54, 60 and 66 ºC. Surviving Salmonella were enumerated at intervals during the cooking process. Isothermal survival curves were described by the Weibull distribution, log S (t) = -b (T) tn(T), and its simplified form as a linear equation (n=1). Nonlinearity was observed in Salmonella survival curves. The We...

Comparison of Angiotensin I-Converting Enzyme Inhibitor Activities of Pre-Fermented Douchi (a Chinese Traditional Fermented Soybean Food) Started with Various Cultures

International Journal of Food Engineering — Sun, 05 Jul 2009 05:26:14 +0100

Pre-fermented douchi, also called douchi qu, is a salt-free semi-product of a Chinese traditional fermented soybean food (douchi), which is classified into three types, that is, Aspergillus-type, Mucor-type and Bacteria-type. In this work, angiotensin I-converting enzyme (ACE) inhibitor activities of douchi qu started by different types of cultures were compared. It was found that douchi qu fermented with Aspergillus oryzae, Mucor wutungkiao, Bacillus subtilis natto and Bacillus subtilis B1 showed significantly different (p < 0.05) ACE inhibitor activities with decreasing IC50 values of 0.4991, 0.3535, 0.2294 and 0.0901 mg/mL, respectively. Twenty-five fractions were separated by gel filtration chromatography and the strongest ACE inhibitor activity was observed in a fraction with high con...

Effect of Pre-Treatment on the Drying Characteristics and Kinetics of Okra (Abelmoschus esculetus (L.) Moench) Slices

International Journal of Food Engineering — Sat, 27 Jun 2009 10:48:32 +0100

The effects of air temperature (50, 60 and 70°C), sample thickness (2, 4 and 6mm) and pretreatment conditions (hot water blanching, 1 and 3% sodium metabisulphite solutions) on the drying characteristics and kinetics of okra were investigated using a convective hot air dryer at a flow rate of 1.5m/s. It was observed that pretreatment conditions, sample thickness and drying air temperature significantly (P (Source: International Journal of Food Engineering)

Computer Modelling and Simulation of Bakeries' Production Planning

International Journal of Food Engineering — Fri, 15 May 2009 23:25:39 +0100

This study gives a real-life example of how to use ARENA to model a complete production line in an efficient way. (Source: International Journal of Food Engineering)

Effect of Fines on Agglomeration in Spray Dryers: An Experimental Study

International Journal of Food Engineering — Tue, 05 May 2009 23:29:15 +0100

Agglomeration in spray dryers occurs by overlapping the spray patterns of multiple liquid nozzles and the airstreams containing recycled fine powder. In this work, the role of the recycled fines stream is explored by measuring the extent of agglomeration. Two scales are investigated, a small-scale dryer with nominal capacity of ~ 1 kg/h and a pilot-scale dryer of ~ 75 kg/h. Experiments were designed to investigate a number of parameters at three levels: low, medium and high about midpoints that represent typical operation at each scale. These operating points are representative of those available, or potentially available, to operators of agglomerating spray dryers: spray flow rate, spray solids concentration, spray droplet size, powder flow rate, and powder particle size. Drying conditio...

Drying Strategies for Fluidized-Bed Drying of Paddy

International Journal of Food Engineering — Tue, 05 May 2009 23:29:12 +0100

The main objective of this work was to determine an effective moisture diffusivity of long grain rice during fluidized-bed drying (FBD) with inlet drying temperatures ranging of 40-150°C by 10°C/step and to investigate the specific energy consumption of the FBD process. Three initial moisture contents of the local indica paddy were set at 25.0, 28.8 and 32.5% dry-basis. The experimental results of thin-layer fluidized-bed drying for the long grain rice variety were determined and statistically analyzed by non-linear regression method. The results showed that an effective diffusion coefficient was highly dependent on the drying temperature, compared to initial moisture content. Consequently, the mathematical simulation of FBD, using the developed thin-layer drying mentioned above, was eva...

Study on β-Galactosidase Isolation, Purification and Optimization of Lactose Hydrolysis in Whey for Production of Instant Energy Drink

International Journal of Food Engineering — Fri, 24 Apr 2009 07:45:12 +0100

Four yeast cultures, Kluyveromyces marxianus, Kluyveromyces fragilis, Saccharomyces marxianus and Saccharomyces fragilis, were selected for isolation of β-galactosidase. Enzyme activity was measured for all four strains and found Kluyveromyces marxianus (177 ONPG unit/ml) to have the highest activity. Experimental whey was hydrolyzed with the enzyme extracted from K. marxianus, and the concentrations of enzyme used were 0.5, 1.0, 1.5, 2.0 and 2.5 ml of enzyme per litre of whey. The percentage of lactose hydrolysis was found to be a maximum of 80% in 60 minutes time for the enzyme concentration of 2.0 ml/ litre of whey. (Source: International Journal of Food Engineering)

Induction and Repression Kinetics of Fungal Beta-Fructofuranosidase in Submerged Culture

International Journal of Food Engineering — Wed, 22 Apr 2009 10:46:03 +0100

Invertase production by Aspergillus niger in submerged culture was evaluated under different concentrations of sucrose and glucose. When the initial concentration of sucrose was increased from 6.25 to 50 gL-1, a higher biomass production (6.1 gL-1) was observed. The biomass production was increased 4 times more when a glucose-sucrose combination was used as substrate (26.31 gL-1). The strain A. niger produced extracellular beta-fructofuranosidase activity at all test concentrations of the substrate and the highest enzymatic activity (3873 UL-1) was obtained when sucrose was used at 12.5 gL-1. However, with a glucose-sucrose concentration of 25 gL-1 the beta-fructofuranosidase activity was of 23706 UL-1. The maximum rate of invertase enzyme production in presence of sucrose by Aspergillus n...

Effects of Incubation Temperature, Starter Culture Level and Total Solids Content on the Rheological Properties of Yogurt

International Journal of Food Engineering — Sun, 12 Apr 2009 04:35:13 +0100

The effects of incubation temperature (35-45oC), starter culture level (0.003-0.006%, w/v), and milk total solids content (12.32-15.68%, w/v) on the rheological properties of yogurt were investigated using central composite rotatable design (CCRD) and response surface methodology (RSM). Gelation time during milk fermentation and apparent viscosity of yogurt stored for 3 days were the rheological parameters studied. The results revealed that the gelation time and apparent viscosity of yogurt were significantly affected (P < 0.1) by incubation temperature, starter culture level, and total solids. Incubation temperature had the greatest influence on the gelation time. Higher temperature led to shorter gelation time, but resulted in lower apparent viscosity of yogurt. Apparent viscosity of yog...

Thermomechanical Property of Rice Kernels Studied by DMA

International Journal of Food Engineering — Sun, 12 Apr 2009 04:35:10 +0100

The thermomechanical property of the rice kernels was investigated using a dynamic mechanical analyzer (DMA). The length change of rice kernels with a loaded constant force along the major axis direction was detected during temperature scanning. The thermomechanical transition occurred in rice kernels when heated. The transition temperatures were determined as 47°C, 50°C and 56°C for the medium-grain rice with the moisture contents of 18.1%, 16.0% and 12.5% (wet basis), respectively. Length change of the rice kernels increased with the increase of the temperature and moisture content. Among the four rice varieties investigated, the results showed that the thermomechanical property was not significantly affected by variety. (Source: International Journal of Food Engineering)

The Effect of De-Oiled Rice Bran for Single Cell Protein Production Using Fungal Cultures under Solid State Fermentation

International Journal of Food Engineering — Sun, 12 Apr 2009 04:35:07 +0100

In the present work, de-oiled rice bran (DOB) was exploited for SCP production using three different fungi, namely, Aspergillus oryzae MTCC 1846, Trichoderma viride NRRL 1186 and Aspergillus niger MTCC 1842 under solid state fermentation. DOB was found to contain 9% protein, 39% cellulose, 28% hemicellulose and 24% lignin. All the three cultures have shown more specific growth rate when grown on glucose in comparison to maltose and cellulose. The specific growth rates on glucose were 0.203, 0.201 and 0.196 h-1 and on maltose were 0.173, 0.171, 0.169 h-1 for A. oryzae MTCC 1846, T. viride NRRL 1186 and A. niger MTCC 1842, respectively. All the three microorganisms showed lowest specific growth rate on cellulose 0.119, 0.117, 0.114 h-1 for A. oryzae MTCC 1846, T. viride NRRL 1186 and A. nige...

Discriminating Structural Characteristics of Starch Extrudates through X-ray Micro-tomography using a 3-D Watershed Algorithm

International Journal of Food Engineering — Fri, 03 Apr 2009 00:29:59 +0100

X-ray micro-tomography (XMT) was used to characterise the pore structure of two open-cell biopolymer foams (starch extrudates). A three-dimensional watershed algorithm was applied to XMT images to segment pore structure. Distributions of pore sizes and interconnecting pore aperture sizes were determined and pore geometry was visualised. The technique was used to analyse samples having an inhomogeneous porosity distribution. Results were not sensitive to threshold values set during image analysis. Pore size and pore aperture distributions were extracted. Pore size was based on volume fraction, aperture size was based on area fraction and both on number frequency. Volume fraction of porosity was calculated from image analysis and compared with that deduced from density measurements. The valu...

Lipase-Catalyzed Acyl-L-Carnitines Synthesis in [Bmim]PF6 Ionic Liquid

International Journal of Food Engineering — Tue, 31 Mar 2009 01:59:52 +0100

In order to significantly improve the biosynthesis of acyl-L-carnitines catalyzed by lipase, there must be an efficient and suitable reaction medium that is not only polar but also hydrophobic. [Bmim]PF6, which satisfies the above two requirements, was applied as the medium. The optimal reaction conditions were: for isovaleryl-L-carnitine, 0.22aW, 200mg molecular sieves, 60ºC, 4:1 of molar ratio (fatty acid:L-carnitine), 150rpm and 60h; for octanoyl-L-carnitine and palmitoyl-L-carnitine, 0.22aW, 250 mg molecular sieves, 5:1 of molar ratio (fatty acid:L-carnitine), 200rpm, 48h, 60ºC (octanoyl-L-carnitine) and 65ºC (palmitoyl-L-carnitine). Their overall yields could reach 59.14%, 90.79% and 98.03%, respectively. The yields of isovaleryl-L-carnitine, octanoyl-L-carnitine and palmitoyl-L-ca...

Optimization of a Convective Air Flow Solar Food Dryer

International Journal of Food Engineering — Mon, 16 Mar 2009 19:37:51 +0100

A solar food dryer, previously developed for personal and small community use, was the object of this optimization study. Based on previous research of convective solar food dehydrators, several dryer parameters were identified for this study. Chimney height and dryer product load were two factors tested in a central composite experimental design. Dryer product load was found to produce a maximum efficiency of the dryer when fifteen product-filled trays were inserted in the dryer. Maximum efficiency was observed at the maximum chimney height tested. Post-optimization configuration compared with pre-optimization configuration resulted in a 40% increase in final dry product production per hour of dehydration time. (Source: International Journal of Food Engineering)

Extrusion Processing of Starch Film

International Journal of Food Engineering — Mon, 16 Mar 2009 19:37:48 +0100

Processing behaviors of starch film using a twin screw extruder were studied; in particular the effect of processing conditions, such as temperature, screw speed, feeding speed, and water content, on the extrusion torque and die pressure were systematically investigated. A specific focus of this work was to investigate the effect of amylose/amylopectin ratio containing in cornstarch on the film processing and performances. It was found that the processibility was decreased as the amylose content increased. Pre-mixing and equilibration improve the processibility of starch films, especially for the high amylose starches. The high amylose starches need higher moisture content and temperature for film extrusion. (Source: International Journal of Food Engineering)

Effectiveness of Antioxidant Properties of Fresh and Dry Rhizomes of Curcuma longa (Long and Short Varieties) with Dry Turmeric Spice

International Journal of Food Engineering — Sat, 27 Dec 2008 06:34:12 +0100

The effectiveness of the antioxidant properties of fresh and dry rhizomes of two tropical turmeric species (Curcuma longa) - long and short varieties - and dry turmeric spice powder have been evaluated with 1,1-Diphenyl-2-picryl-hydrazyl(DPPH) and beta - carotene bleaching radical-generating systems. The results showed that the aqueous extract of fresh rhizomes showed higher antioxidant properties as compared to the extracts from dry rhizomes, while the commercially available dry turmeric powder, commonly sold and used as a spice in Indian markets and used as a very common spice in Indian cooking, had the least antioxidant properties. A comparison of the two different species in their two different physical states of rhizomes-fresh and dry, showed considerable loss in antioxidant propertie...

Milk Cholesterol Reduction Using Immobilized Lactobacillus acidophilus ATCC1643 in Sodium-Alginate

International Journal of Food Engineering — Wed, 10 Dec 2008 05:28:54 +0100

In this study, we have investigated the effect of L. acidophilus ATCC 1643 on removing the milk cholesterol and additionally, we have immobilized L. acidophilus ATCC1643 cells in sodium-alginate and observed its effect on milk cholesterol removing. Also, we have researched about the effect of some factors including: bacteria cells number (both free and immobilized cells) and immobilized cells bead size on cholesterol removing rate and ultimately the extracted results were compared together. The results indicated that free cells could reduce cholesterol to lower than 0.5mg/100ml milk. Also, smaller bead size resulted higher cholesterol reduction. Increasing the number of immobilized cells showed significant effect on cholesterol removal to about 86%. Also, reusability of the beads showed th...

Antioxidant Activity of the Flower of Nyctanthes arbor tristis L.

International Journal of Food Engineering — Wed, 10 Dec 2008 05:28:53 +0100

Nyctanthes arbor-tristis (Harshingar, Parijat) belongs to the family Oleaceae. The flower has white petals with an orange calyx. Nyctanthes stems have been found to be a rich source of antioxidant. The aqueous extracts of the flower, calyx and petals were evaluated and found to be dose-dependent and showed an increase in DPPH free radical scavenging activity in vitro. The extracts, which showed strong DPPH radical scavenging activity, are in the order Calyx > flower > petals. This signifies that the main antioxidant activity is in the orange colored calyx of the flower. We have attempted an innovative study with the Nyctanthes flower as a part of an exploration for a cheap natural source of antioxidants which can be used at the industrial scale of the food industry. (Source: International ...

The Purification, Formulation and Drying of Papain

International Journal of Food Engineering — Wed, 10 Dec 2008 05:28:50 +0100

Papain, a proteolytic enzyme was purified from latex of Carica papaya by a variety of techniques such as two-step salt precipitation, organic solvent precipitation (ethanol) and ion exchange chromatography. Fold purity obtained using ion exchange chromatography was in the range of 4.5 to 5 times as compared to the precipitation techniques. The purified papain was entrapped in ionotropically cross-linked alginate beads, in order to develop formulation for site-specific delivery of papain in intestine. The entrapment efficiency for papain in alginate beads was found to be in excess of 86%. Drying at low temperature and low air velocity results into maximum retention of papain activity; however, drying time increases significantly. The dissolution study shows the possible use of alginate bead...

The Effects of Varieties and Moisture Content on Some Physical and Aerodynamic Properties of Sesame Seeds (Sesamum indicum L) as Related to Cleaning

International Journal of Food Engineering — Sat, 29 Nov 2008 00:15:50 +0100

Some physical and aerodynamic properties of two varieties of sesame seeds (Yandev -55 and E8) were determined at varied moisture content levels. These properties are factors in the design and selection of sesame seed-cleaning machines. For the Yandev-55 and E8 varieties, major diameters ranged from 2.8 mm to 3.3 mm and 3.4 mm to 3.8 mm, intermediate diameters ranged from 1.8 mm to 2.1 mm and 2.2 mm to 2.5 mm, and minor diameters ranged from 0.7 mm to 0.9 mm and 0.6 to 0.9 mm, respectively. Their geometric means ranged from 1.5 to 1.8 mm and 1.7 to 2.0 mm, their spheroids ranged from 0.5 to 0.6 and 0.5 to 0.6, and their frontal areas ranged from 1.8 to 2.6 and 2.2 to 3.2, respectively. The terminal velocities of Yandev-55 were 2.9, 3.6, 4.7 and 5.4, while the terminal velocities of E8 were ...

The Transfer of Ingested Plant and Enterobacterial Gene Fragments into Mice Bodies and Their Shift to the Livers of Suckling Mice Through Mother's Milk

International Journal of Food Engineering — Fri, 21 Nov 2008 03:42:09 +0100

The presence of common enterobacterial genes (wec E, F), the ubiquitous plant chloroplast gene of ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL), maize intrinsic zein (Ze1) and recombinant cry1Ab genes in the gastrointestinal (GI) contents, peripheral blood mononuclear cells (PBMC) and visceral organs of mice and their progeny were examined by PCR. The wec E, F or rbcL were detected inconsistently in the PBMC, visceral organs, milk or liver of suckling mice, while Ze1 or cry1Ab were not detected. These results suggest that feed derived plant or enterobacterial DNAs were incompletely degraded in the GI tract, and part of them were absorbed into organs or milk as a source of transfer into suckling mice, but cry1Ab was not transferred. Detection of bacterial genes also s...

Association of Two Enzymes for Obtaining Low Phenylalanine Protein Hydrolysates from Wheat Flour

International Journal of Food Engineering — Wed, 29 Oct 2008 23:25:30 +0100

This work involved the removal of phenylalanine (Phe) from wheat flour which followed three steps: 1. protein extraction using an alkaline protease from Bacillus licheniformis; 2. protein hydrolysis by the action of a commercial enzyme (pancreatin or Panc) in association with a crude enzymatic extract obtained from pineapple peel (CE); 3. use of activated carbon (AC) as adsorbent. The effect of some parameters, such as order of enzyme action, pH and reaction time, was evaluated. The efficiency of Phe removal was assessed by second derivative spectrophotometry, measuring the Phe content in the wheat flour as well as in its hydrolysates after AC treatment. The results showed the advantage of using CE for 1h30min followed by Panc for 3h30min, at pH 7.0, producing 66.28% of removal and a final...

Formulation and Fuzzy Modeling of Viscosity of an Orange-Flavored Carboxymethylcellulose-Whey Protein Isolate Beverage

International Journal of Food Engineering — Tue, 28 Oct 2008 22:35:50 +0100

The aim of this study was to employ whey proteins isolate (WPI) and carboxymethylcelulose (CMC) as stabilizers in beverage production and to evaluate viscosity of the products. Three beverages were formulated using 6% WPI combined with three different concentrations of CMC (0.1, 0.5, and 1%). The combination of 6% WPI/1.0% CMC was selected and added to three different ratios of pure orange juice (50:50 "T1," 40:60 "T2," and 15:85 "T3"). The apparent viscosity decreased as shear rate and temperature increased. Additionally, the apparent viscosity for the same treatment at certain shear rate/same temperature increased after storage. In addition, an adaptive neuro-fuzzy inference system (ANFIS) was used to model and identify the viscosity of the resulted beverages. Experimental validation run...

Indirect Method of Measuring Dispersion Coefficients for Granular Flow in a Column of Dihedrons

International Journal of Food Engineering — Wed, 08 Oct 2008 20:46:13 +0100

In the chemical, pharmaceutical and food-processing industries, the drying operation is a major intermediate step in the production of finished or semi-finished products. There are a great many drying processes and types of equipment, such as dryers with immersed channels; the main advantage of this type of dryer is the homogeneous distribution of the drying air, made possible by dihedrons, a special device for introducing the air. The basis tool for dimension, a drier with immersed channels, is the control of the dehydration of the product, and the distribution function residence time of the particles inside the column. In the present study, a model and thus an indirect measurement of dispersion coefficients of solids were proposed in contrast with previous studies where the variation of ...

Application of Atomic Force Microscopy on Studying Micro- and Nano-Structures of Starch

International Journal of Food Engineering — Tue, 23 Sep 2008 05:36:42 +0100

This paper reviews the application of atomic force microscopy (AFM) to the study of starch structures, including both macrostructure of starch granules and the nanostructure of molecular chains. It introduces the different techniques of sample preparation and discusses what AFM could observe. The paper summarises the present situation of the application of AFM in the study of starch structures and guides the direction for further research. (Source: International Journal of Food Engineering)

Variation of the Physical Properties of Sheanut (Vitellaria Paradoxa Gaertn.) Kernels during Convective Drying

International Journal of Food Engineering — Fri, 19 Sep 2008 21:46:50 +0100

The effect of moisture content and drying temperature of Vitellaria paradoxa Gaertn kernels on some of its physical properties was investigated. The kernels which were harvested at a moisture content of about 60% (wet basis) and hence prone to high post harvest losses from two ecological zones of Cameroon (Bangoua in West province and Tchabal in Adamawa province) were dried in a forced convection dryer at 40oC, for 6, 20, 48, 72 and 96 hours to give moisture contents ranging from 10 to 60% wet basis. Ten trees from each of the zones were carefully selected to serve as sources for the ripe kernel bearing shea fruits that were used as samples for this study. For each parameter studied, a sample population of 30 kernels selected at random per tree was used. The results obtained revealed that ...

Effectiveness of Pulsed Electric Fields in Controlling Microbial Growth in Milk

International Journal of Food Engineering — Wed, 27 Aug 2008 23:29:08 +0100

A study was conducted to assess the effectiveness of pulsed electric field (PEF) inactivation of a heterogeneous community of microbes. The aim was to assess the impact of process parameters on an indigenous population of microbes present in milk, rather than pure cultures used in other studies. Tests over an electric field strength range of 10 - 40 kV/cm and 10 to 120 pulses per millilitre showed that high electric field strength and pulse number inactivated microbes by up to approximately 2 log. Inoculum size affected PEF effectiveness when only a few pulses were applied. A significant log-reduction was achieved against the indigenous microbes found in milk that were apparently recalcitrant to commercial pasteurization. Microbial inactivation was more extensive when E. coli was not added...

Fruits & Vegetables Drying Combining Hot Air, DIC Technology and Microwaves

International Journal of Food Engineering — Wed, 20 Aug 2008 03:57:12 +0100

Dehydration of fruits and vegetables is one of the most ancient and efficient preservation methods. The quality of the product and its cost depend mainly on the final stage of drying. In the present paper we analyze physical mechanisms occurring during drying throughout heat and mass transfer for defining an efficient and economic three stage drying process of hot air drying combined to a texturing stage by DIC (Instant Controlled Pressure Drop) and finally using microwave assisted by ambient temperature air dehydration. (Source: International Journal of Food Engineering)

Effects of Heat and Pulsed Electric Fields on Bioactive Components and Color of Green Tea Infusions

International Journal of Food Engineering — Wed, 13 Aug 2008 23:58:08 +0100

Green tea is an unfermented tea containing a higher quantity of bioactive components. It has received a great deal of attention due to many biological activities, such as antioxidative, anticarcinogenic and antitumour activities. However, deterioration in quality after heating processes, in particular sterilization, was technical barrier for commercial ready-to-drink green tea production. It has already been demonstrated that pulsed electric fields (PEF) processing can alternatively be applied to deliver safe and shelf-stable products. In this paper the effect of conventional heat treatment (121 oC, 3min) and PEF treatment on the bioactive components (polyphenols, catechins and free amino acids) and color of green tea infusions was studied. There was a significant (P (Source: International...

Design of Hybrid Drying- Dedusting Unit Processor for Rough Rice Processing

International Journal of Food Engineering — Wed, 13 Aug 2008 21:27:19 +0100

The objectives of the study was to investigate the separation efficiency of dedusting of rice husks in the two-stage cross flow fluidized bed dryer and to study the drying kinetics of rough rice drying in the batch fluidized bed dryer. The experimental results showed that the dedusting separation efficiency at low superficial gas velocity gave unsatisfactory separation of merely 40% of rice husks. At higher superficial gas velocity, separation efficiency of rice husks as high as 93% was achieved. In addition, higher distributor inclination angle gave slightly improved separation efficiency. The drying kinetics showed that the residence time that is required to reduce the moisture content of rough rice to 18% (intermediate storage moisture content for second stage drying) is 3 minutes where...

Guest Editorial

International Journal of Food Engineering — Mon, 11 Aug 2008 23:39:48 +0100

(Source: International Journal of Food Engineering)

Modeling of the Mass Transfer Effect in Biphasic Enzyme Membrane Reactor for Hydrolysis of Olive Oil

International Journal of Food Engineering — Wed, 06 Aug 2008 00:04:35 +0100

This article presents a model to explain the mass transfer phenomenon of the ions (OH-, Na+ and RCOO-) formed during the hydrolysis reaction on the aqueous side of the reaction sites in the biphasic enzyme membrane reactor (EMR) using lipase immobilized on modified poly (methyl methacrylate-ethylene glycol dimethacrylate) (PMMA-EGDM) clay composite membrane. Our model divides the aqueous side of the system into two regions, an unstirred film (aqueous side) adjacent to the pore end (region I) and charged capillaries of the membrane (region II). The process involves transport of Na+, OH- and RCOO- ions in region I whereas the film is considered as an electro-neutral region. Space charge model (consisting of Nernst-Planck equation for ion transport and nonlinear Poisson-Boltzmann (PB) equatio...

Fermentative Production, Purification and Characterization of Nisin

International Journal of Food Engineering — Mon, 04 Aug 2008 23:41:11 +0100

The objective of the present work was to study production, purification and characterization of nisin. The production of nisin was carried out using Lactococcus lactis subsp lactis MTCC 440 by one-factor-at-a-time method and statistical design (Orthogonal array). Purification was carried out using ammonium sulphate precipitation followed by hydrophobic interaction and gel chromatography. Characterization was done for pH and temperature stability. The activity of nisin after one factor at a time optimization was found to be 5120 AU/ml. The activity of the nisin increased to 6800 AU/ml after optimization by Orthogonal Array design. Ammonium sulphate precipitation gives good yield of nisin with 60 to 80% saturation with 2.52 fold purity. The overall purification by hydrophobic interaction and...

Effect of Pretreatments on Air Drying of Papaya Cubes

International Journal of Food Engineering — Mon, 04 Aug 2008 22:28:41 +0100

Among various methods of preservation for fruits and vegetables, drying being simple, it is widely practiced from very ancient times. Papaya cubes were treated with Sodium meta bisulphite, Calcium chloride, blanching and their combination as pretreatments before air drying at 50oC and compared with the control sample. The time required for dehydration was comparatively less for the pretreated samples than control samples. The rehydration ratio of samples pretreated with blanching and Sodium meta bisulphite was observed maximum as 2.96. (Source: International Journal of Food Engineering)

Droplet-Particle Agglomeration of Maltodextrin and Salt in a Small-Scale Spray Dryer

International Journal of Food Engineering — Tue, 29 Jul 2008 21:30:00 +0100

The technique of in-chamber blending in practice has been investigated, by altering the configuration of a Buchi B290 small-scale spray dryer having a two-fluid nozzle, through adding an extra pipe into the chamber to agglomerate maltodextrin (DE18) particles with 20% salt solution sprayed through the atomizer. Scanning Electron Micrographs showed the importance of splash impacts between salt droplets and maltodextrin particles in this geometry, suggesting that the collision efficiency is strongly affected by whether or not the salt droplets completely surround the dry maltodextrin particles. Changing the air inlet temperature did not affect the measured amount of collisions (from Atomic Absorption Spectroscopy) significantly, but both the main air and the nozzle air flow rates had signifi...

Optimization of Osmotic Dehydration of Toona Sinensis Leaves Using Response Surface Methodology

International Journal of Food Engineering — Tue, 29 Jul 2008 21:06:11 +0100

Toona Sinensis leaves were dehydrated by osmosis. The effects of temperature, immersion time, sucrose and salt concentration on water loss and solid gain during osmotic dehydration were investigated by response surface methodology. Consequently, second order polynomial models were developed for water loss and solid gain as a function of the experimental parameters. By applying Excel's Solver feature, an optimal solution for maximum water loss and minimum solid gain was given at temperature of 30oC, sucrose concentration of 50%, salt concentration of 10%, and immersion time of 4 hours. (Source: International Journal of Food Engineering)

Sorption Drying of Soybean Seeds with Silica Gel in a Fluidized Bed Dryer

International Journal of Food Engineering — Tue, 29 Jul 2008 21:06:07 +0100

Soybean seeds were contacted with silica gel in a fluidized bed, where mass transfer is driven by moisture concentration gradient. It has the advantage of well-mixing the solid adsorbent (silica gel) with the material being dried (soybean seeds) in fluidization state, and thus the dried seeds quality could be improved since they are in a uniform environment of low humidity. The drying kinetics was compared under different mass ratios and fluidization conditions. The drying rate was improved with the gas velocity and mass ratio of silica gel. A scheme of sorption drying in a hybrid process of fluidized/fixed bed is proposed in the viewpoint of energy efficiency and product quality. (Source: International Journal of Food Engineering)

Rheological Properties of Diluted Pummelo Juice as Affected by Three Different Concentrations

International Journal of Food Engineering — Sat, 12 Jul 2008 02:00:58 +0100

Pummelo is a popular fruit that has great potential to be commercialized. The physico-chemical characterization of pummelo juice such as proximate analysis, pH, moisture content, protein, fat, carbohydrate, ash and fibre contents are investigated. The rheological characterization of pummelo juice was modeled by several models, such as Bingham, Power Law and Casson models. Regression analysis shows good agreements for all three models applied in this study. Pummelo juice exhibits pseudoplastic behaviour under the conditions tested, as indicated by flow behaviour indices (n) ranging from 0.1 to 0.9 from power law model, indicating strong shear-thinning behaviour. (Source: International Journal of Food Engineering)

Efficacy in Microbial Sterilization of Pulsed Magnetic Field Treatment

International Journal of Food Engineering — Tue, 08 Jul 2008 08:48:23 +0100

Sterilization effects of the pulsed magnetic field with a maximum intensity of 11.37 Tesla were investigated on Escherichia coli AS 1.129, Staphylococcus aureus AS 1.89, Saccharomyces cerevisiae ATTC 7552 and Bacillus subtilis AS 1.921. The well-regulated fluctuations of sterilization effects with magnetic field intensity and pulse number were observed, and can be described by the "window effect" of magnetic fields and provide a better explanation of the inconsistent results of PMF sterilization in published literature. Sensibility of bacteria on the pulsed magnetic field significantly depends on a variety of microorganisms. Sterilization effects of a flowing sample were better than that of static samples. (Source: International Journal of Food Engineering)

Inhibition of Food-Borne Pathogens by T1, a Novel Antimicrobial Peptide as a Potential Food Preservative

International Journal of Food Engineering — Tue, 24 Jun 2008 10:59:18 +0100

An efficient and convenient purifying procedure for recombinant peptide was established. Thereby, the aimed antimicrobial peptide T1 containing the conservative sequences derived from cecropin was successfully expressed and purified. The composition of amino acid of the purified peptide T1 was consistent with that of theoretical design. The significant antimicrobial activity of T1 against gram-positive and gram-negative bacteria was demonstrated, suggesting that the conservative sequences in cecropin play an important role in the antimicrobial mechanism and that antimicrobial peptide T1 has the potential to be used as the food preservative. (Source: International Journal of Food Engineering)

Effect of Heat Treatment on Pectic Fractions and Apparent Viscosity of Whole Blackberry (Rubus spp.) Pulp

International Journal of Food Engineering — Tue, 24 Jun 2008 10:59:08 +0100

The aim of this work was to study the influence of temperature on pectic fractions and apparent viscosity of whole blackberry pulp. The fractions soluble in water, oxalate, acid and alkali, containing pectic substances, were evaluated with temperature increase. A concentric cylinder Brookfield rheometer with a small sample adapter was used to obtain the rheological parameter of shear stress, in order to calculate the apparent viscosity of the pulp. The water soluble pectin (WSP) increased and the water insoluble pectin (WIP) decreased with a continuous increase in heat treatment. The decrease in apparent viscosity had a good correlation with the increase in water soluble pectin (r=0.94) as a function of temperature. (Source: International Journal of Food Engineering)

Optimization of Supercritical Carbon Dioxide Extraction of Flaxseed Oil Using Response Surface Methodology

International Journal of Food Engineering — Tue, 27 May 2008 05:39:58 +0100

The optimal conditions for the supercritical carbon dioxide (SC-CO2) extraction of flaxseed oil from flaxseed were determined using response surface methodology (RSM). A second-order regression for rotation-orthogonal composite design was used to study the effects of three independent variables: extraction pressure (MPa), extraction temperature (oC) and CO2 flow rate (L/h) on the yield of flaxseed oil. The independent variables were coded at five levels and their actual values selected on the basis of preliminary experiments. The results indicated that the yield of flaxseed oil was beyond 29% at a probability of 95% in the range of extraction pressure: 38.6-42.3 MPa, extraction temperature: 52.3-57.0 oC, and CO2 flow rate: 27.8-31.2 L/h. The optimal extraction conditions were extraction pr...

Producing Powders of Hibiscus Extract in a Laboratory-Scale Spray Dryer

International Journal of Food Engineering — Fri, 23 May 2008 07:44:41 +0100

The production of powder from hibiscus extract with the possible addition of maltodextrin or fine citrus fibre has been investigated in a small-scale Buchi B-290 spray dryer to assess the drying yields and outlet moisture contents. The yields ranged from 24-58%, with inlet temperatures from 150oC to 210oC, solids concentrations in the extract of 11.4% and 25.9%, and the addition of 0.9-5.7% fine citrus fibre or 1% maltodextrin. At the same solids concentration, the inlet gas temperature was found to improve the yield. The drying behaviour appears to be kinetically limited. The inlet gas temperature has the most significant effect on the yield, with a 95% confidence level. For the outlet moisture contents, the effects of fibre, the amount of solids in the extract and the inlet gas temperatu...

Different Strategies of Far-Infrared Radiation Application in Paddy Drying

International Journal of Food Engineering — Thu, 22 May 2008 00:24:53 +0100

The applied strategy of far-infrared radiation in paddy drying is divided into two main processes with some overlapping, namely, series and combined drying processes. The first comprises fluidized-bed drying, far-infrared radiation, tempering and ambient air ventilation as well as transport of paddy, and the latter is the combination of far-infrared radiation and hot-air convection in fluidization technique. The changes of average moisture content, grain temperature and milling quality in each paddy drying process are presented together with mathematical models. The experiments showed that series drying process was more effective to apply in the aspects of paddy drying and milling qualities than combined drying process. Due to less effectiveness in combined drying process, heat and mass tr...

Development of a Microwave Treatment Technique for Bacterial Decontamination of Raw Meat

International Journal of Food Engineering — Thu, 08 May 2008 07:08:54 +0100

The present study developed and verified a 'cold' microwave (MW) treatment that could lead to the inactivation of two common pathogenic species of bacteria, Escherichia coli and Staphylococcus aureus, in raw meats. A number of experimental conditions were designed and tested to maximise MW exposure without overheating the samples. The non-thermal effect was maximised by multiple exposure to attain efficient MW threshold intensities. It was shown that at sub-lethal temperatures repeated exposure using high frequency MW radiation was significantly more effective in decontaminating bacteria in raw meats compared to a single exposure. It was concluded that non thermal inactivation of pathogenic bacteria in raw meats could be achieved at defined conditions using high frequency MW radiation. (So...

A Comparative Study of Sensitivity of Acetylcholinesterase in Detection of Organophosphorus Pesticide Residues

International Journal of Food Engineering — Thu, 08 May 2008 07:08:49 +0100

In this paper, four enzymes from different sources used for pesticide detection were tested and compared: homogenate from chicken liver, chicken brain and cyprinoids brain were made respectively in the laboratory and Acetylcholinesterase (AChE) was purchased from Musca domestica. The inhibition of AChE activity under different concentrations of omethoate, trichlorfon and dichlorvos were compared. The results showed that the AChE activity in chicken liver and cyprinoids brain were very low. The capacities of activity inhibition of other two kinds of AChE were better. Chicken brain-esterase's inhibition rate achieved 24.16%, 50.56%, and 54.1% for 100ug/L of omethoate, trichlorfon and dichlorvos respectively. Chicken brain-esterase has high specific activity, is low cost, and easy to prepare,...

Modeling Drying Kinetics of Mustard in Fluidized Bed

International Journal of Food Engineering — Wed, 07 May 2008 04:06:31 +0100

Mustard (Brassica juncea), one of the popular oil seeds, is investigated for drying in Batch fluidized beds. Experiments were conducted to assess the kinetics of drying for the variation in the inlet air temperature, the inlet air flow rate and the solids holdup in the fluidized bed. The drying rate was found to increase significantly with increase in temperature and with flow rate of the heating medium, while decrease with increase in solids holdup. The duration of constant rate period was found to be insignificant, considering the total duration of drying. The drying rate was compared with various exponential time decay models and the model parameters were evaluated. The page model was found to match the experimental data very closely with the maximum root mean square error (RMSE) of les...

Modeling of Oil Palm Fruit Maturity for the Development of an Outdoor Vision System

International Journal of Food Engineering — Wed, 07 May 2008 04:06:21 +0100

In this study, the matured FFB was captured using a Sony digital Handycam on the day shift period. At the same time period of daylight intensity, a unit on foot candles (FC) also was simultaneously recorded using an Extech lightmeter data logger. From the linear regression analysis process, the mathematical model shows that there is a linear change between daylight intensity with the pixel value of the components green and blue. For the pixel value of the red component, the value will be linear at a maximum of 255 and at a certain intensity. To validate the mathematical model, this equation is used in the development of software for outdoor recognition processes. (Source: International Journal of Food Engineering)

Comparative Study of Total Phenol, Flavonoid Contents and Antioxidant Activity in Canna indica and Hibiscus rosa sinensis: Prospective Natural Food Dyes

International Journal of Food Engineering — Wed, 07 May 2008 04:06:18 +0100

In the present study the comparative data of total phenol and total flavonoid contents along with antioxidant activity were assessed in native Canna indica. Total phenolic contents were analyzed by a Folin-Ciocalteu reagent and antioxidant activity was analyzed by DPPH assay and TEAC assay, in crude methanolic extracts of red, yellow varieties of Canna indica and red variety of Hibiscus rosa sinensis. DPPH assay of crude extracts taking pyrogallol as standard show that fresh red canna extract has best results for radical scavenging. Stability of color content of canna towards pH and its pKa were assessed. Colorimetric analysis of crude extracts showed red canna extract to be the best in terms of its tinctorial strength, a pre-requisite for a food dye. On the basis of the results obtained, ...

Mathematical Models for Prediction of Rheological Parameters of Pineapple Juice

International Journal of Food Engineering — Wed, 07 May 2008 04:06:11 +0100

Rheological characteristics of pineapple juice have been investigated and rheological parameters were evaluated using rotational viscometer at temperatures 20, 30 and 40*C at concentration 26.77, 18.99 and 14 % total solids. The experimental results followed the power law model for the best fit and the values of flow behaviour index (n) was less than unity (0.08 to 0.87) at all temperatures and concentrations indicating the shear thinning (pseudoplasticity) nature of juice. An obvious correlation between consistency coefficient in the range of 0.1 - 37.16 Pa.sn and inverse absolute temperature has been exhibited by Arrhenius model. The Power equation indicated that the consistency coefficient increased non-linearly with an increase in concentration. Mathematical models were developed for p...

Ohmic Heating Behavior of Certain Selected Liquid Food Materials

International Journal of Food Engineering — Tue, 22 Apr 2008 06:10:10 +0100

In this study, an experimental ohmic heating unit was designed and fabricated. Four kinds of liquid food materials (tap water, fruit-vegetable juice, yogurt and 0.5% aqueous sodium chloride solution) were heated on this laboratory scale static ohmic heater to evaluate the device's performance. Different voltage gradients (7.5V/cm, 11.25V/cm, 15V/cm, 18.75V/cm, 22.5V/cm and 26.25V/cm) were applied to study the heating behavior of liquid food materials. Results indicated that the voltage gradient significantly influenced the ohmic heating rates for all four materials tested. The electrical conductivity also changed significantly with temperature. (Source: International Journal of Food Engineering)

Analysis of Dough Sheeting and Heat Transfer during Baking of Unleavened Flat Bread (Chapathi)

International Journal of Food Engineering — Sat, 19 Apr 2008 06:27:42 +0100

Unleavened Indian flat bread (Chapathi) is widely consumed by a large section of the population. An automatic unleavened flat bread making device (Chapathi) is designed and developed; it consists of a sheeting and a baking device. The prototype device is used for the preparation of Chapathis. The observations made during these experimentations are used for the improvement of the device. The sheeting characteristics of Chapathi dough prepared from Atta and whole wheat flour with varying levels of water is studied. The trials indicated that the consistency of the dough to be about 110 s for Atta and 120 s for whole wheat flour and the pressure required to extrude the dough to be in the range 3.43*105~4.41*105 Pa. It is observed that 0.8*10-3 m slit width is optimum to get a Chapathi sheet th...

Air-impingement De-shelling of Chestnuts (C. mollisima): Process Parameter Optimization

International Journal of Food Engineering — Fri, 04 Apr 2008 16:40:26 +0100

Presently in China de-shelling of chestnuts is done manually, which is tedious, time consuming and labor intensive. The de-shelling operation has become the greatest problem and poses a bottleneck to the chestnut processing industry in China. To overcome this problem, the objective of this study is to derive optimum conditions for chestnut de-shelling using air-impingement de-shelling technology. Response surface methodology was employed to analyze the effects of air temperature (163-197oC), processing time (109-311s) and air velocity (6.68-9.73m/s) on the rate of water loss, de-shelling rate and lightness. Prediction models were also established. Optimum conditions obtained were 179oC of air temperature, 278s of processing time and 7.83m/s of air velocity. Values predicted by the models f...

Discrimination of Wines Produced from Cabernet Sauvignon Grapes Treated with Aqueous Ethanol Post-Bloom Using an Electronic Nose

International Journal of Food Engineering — Fri, 04 Apr 2008 16:40:23 +0100

Wine discrimination and analysis is typically done through chemical analysis and sensory evaluation by a trained panel. Both of these methods are proven to be successful in wine discrimination, but require extensive preparation, time and money. The electronic nose is an objective, rapid-analysis tool that has been used in the food industry for a number of applications. The purpose of this study was to determine if an electronic nose can accurately discriminate between Cabernet Sauvignon (Vitis vinifera L.) wines made from grapes that have received different pre-harvest but post-bloom spray treatments to enhance growth.Aqueous ethanol, which has been shown to impact fruit maturity, was sprayed on the grape clusters at 13 weeks post bloom in different concentrations (control, 5% and 10% v/v)...

Enzyme Hydrolysis of Silk Fibroin and the Anti-diabetic Activity of the Hydrolysates

International Journal of Food Engineering — Fri, 04 Apr 2008 16:40:19 +0100

The degradation behavior of Silk Fibroin (SF) by elastase was investigated. The inhibitory effects of the hydrolyzed solution on α-glucosidase were also examined. Elastase follows Michaelis-Menten kinetics with Km and Vm values of 14.49 mg/ml and 1.96 μmol/min, respectively, and the SF peptides with Km and Ki values of 3.8 mg/ml and 3.55 mg/ml. The inhibition effect of the peptide solution on α-glucosidase was found to be noncompetitive and reversible. The hydrolyzed fragments with molecular weights under 6 kDa exerted the prominent inhibiting effect on mice α-glucosidase, with the inhibition activity of 36.6 - 38.9%. These results suggested that SF peptides might exert anti-diabetic effect by suppressing carbohydrate absorption from the intestine, and thereby decrease the postprandial...

Combined Radiant and Conductive Vacuum Drying in a Vibrated Bed

International Journal of Food Engineering — Wed, 02 Apr 2008 13:02:49 +0100

The objective of this experimental project is to design, build and test a laboratory size vibrated drum dryer under vacuum. The basic concept is to design a variable frequency, variable amplitude vibratory unit on which a horizontal drum is seated. An experimental approach was employed to permit simultaneous or individual mode of conduction and radiation heat input. Cube shaped potatoes and apples were used as model samples for experimental tests. Experiments were also performed using spherical shaped silica gel. Five different drying conditions were compared experimentally. These are: case-1, effect of vacuum; case-2, vacuum with vertical sinusoidal vibration (Amplitude: 0-5mm, frequency: 10-50 Hz); case-3, vacuum with vibration and conduction heat input (40C); case-4, vacuum with vibrati...

Numerical Simulation of the Water Diffusion in Cylindrical Solids

International Journal of Food Engineering — Fri, 21 Mar 2008 06:09:17 +0100

In this article, a mathematical model was developed for the numerical simulation of the water diffusion in an infinite cylinder. A solver for the diffusion equation was created using the finite volume method, with a fully implicit formulation. In order to create such solver, it was assumed that the boundary condition of the first type is adequate to simulate the physical problem. The solver presupposes variable thermophysical properties and radius in the domain. In order to determine the parameters of the expression between the diffusivity and the moisture content, an optimizer was created, based on the inverse method. The developed mathematical model was applied to simulate the drying of banana and rough rice, using experimental data obtained from the literature. The results obtained in t...

Optimisation of Cassava Pellet Processing Method

International Journal of Food Engineering — Tue, 11 Mar 2008 04:36:12 +0100

Processing cassava onto pellets, an internationally acceptable and commercially rewarding cassava product minimizes quantitative and qualitative losses. Pellet samples were produced through the conventional chipping, drying, milling then pelleting with and without steaming (CDMP-S and CDMP) and modified process of grating, dewatering then pelleting and steaming (GDWP-S). Investigations for storageability, durability, uniformity in dimension and nutritional qualities resulted in pellets with moisture content of 9%, uniformly light brown in colour, free from objectionable odour with no sign of deterioration after 90 days of storage. The durability index and fine formations are 99.8% and 0.2%, 98.8% and 1.2%, 99.4% and 0.6% for CDMP-S, CDMP and GDWP-S respectively. The average lengths of 2.81...

Equilibrium Moisture Content Models for Lafun

International Journal of Food Engineering — Thu, 06 Mar 2008 22:25:35 +0100

Insights into the relationship between the air relative humidity (water activity (aw)) and equilibrium moisture content of food materials is essential to maintain good keeping quality and optimize process operation. The adsorption isotherms for cassava flour (lafun) were investigated with the static gravimetric method. Concentrated acid (H2SO4) solutions were used to vary the micro-climate in the study and presented in an easy-to-use template-like format over the range of temperature (27- 40oC) and aw (0.10-0.80) usually experienced in the tropical environment. The experimental data were compared with five widely recommended models in the literature for food sorption isotherms (GAB, modified GAB, modified Oswin, modified Henderson & modified Chung-Pfost). The moisture sorption isotherms we...

Simulation of an Effect of a Baffle Length on the Power Consumption in an Agitated Vessel

International Journal of Food Engineering — Thu, 06 Mar 2008 22:25:31 +0100

Agitated vessels are often used for homogenization of the miscible liquids in chemical, biochemical, and food industries. Computational fluid dynamics (CFD) is a useful tool for studying fluid flows, including those of mixing systems. It is particularly powerful where the ability exists to corroborate model results with available data. The CFD simulation was carried out for Rushton and Smith turbines agitators. The standard k-ε model has been used for turbulence modeling. The data obtained by simulation are matching with the literature experimental value for standard baffle with the discrepancy of less than +_4.5% for power number. The simulated results for agitated vessel with short baffle (non-standard) are agreeing with the literature values within plus or minus 5% for Power Number. (S...

Fatty Acid Composition of Turkey Meat Sucuk (Soudjuck), Salami, and Sausages

International Journal of Food Engineering — Tue, 04 Mar 2008 11:41:34 +0100

In this paper, the fatty acid composition of turkey meat sucuk (soudjuck), salami, and sausages were determined and compared with each other. The fatty acids methyl esters of each product were identified by capillary gas chromatography. Most of the fatty acids in sucuk (soudjuck) samples were monosaturated; however in salami and sausages samples most of were mono and di-unsaturated. Saturated fatty acids in sucuk (soudjuck) samples followed, having the palmitic and stearic acids as their major components and had a range of 229.7-385.2 g kg-1 and 87.6-215.9 g kg-1. In salami and sausages samples, unsaturated fatty acids, the oleic and linoleic acids were the major components and had a range of 170.0-542.0 g kg-1 and 151.5-353.0 g kg-1. PUFA (polyunsaturated fatty acids) were found for sausa...

Recovery of Polyphenolics from Apple Juice Utilizing Adsorbent Polymer Technology

International Journal of Food Engineering — Tue, 12 Feb 2008 22:35:10 +0100

A food grade divinylbenzene adsorbent resin was used to separate/recover plyphenolics from diluted apple juice concentrate. The work was carried out to investigate the effect of processing parameters on the adsorption process, to compare the efficiency of divinylbenzene adsorbent resin to that of ethylene glycol cross-linked polymethylmethacrylate adsorbent resin used in our previous study and to determine the effect of oxygen on the adsorption of polyphenolics process. A laboratory scale adsorption was determined by mixing weighed amounts of the polymer with a diluted apple juice concentrate at 10-60 oC and at pH values ranging from 2.0 to 3.9. At regular intervals, samples were withdrawn from the aqueous phase. Total phenolics, absorbance values at 280 and 420 nm, and the amounts of indi...

Stabilization of Moisture Sorption in Spray-Dried Bioactive Compounds by Using Novel Fibre Carriers to Crystallize the Powders

International Journal of Food Engineering — Tue, 12 Feb 2008 22:35:04 +0100

Natural fruit fibres have been used when spray drying a bioactive material, hibiscus extract, which contains significant amounts of anthocyanin. The extracts, when spray dried alone, produce powders that adsorb so much moisture that they deliquesce, forming liquid droplets in storage. The use of these fibres has demonstrated that the resulting extract and fibre powders do not deliquesce and reach a stable moisture state as powders. This situation of greater stability in the extract and fibre powders, regarding moisture sorption, than the spray dried extracts alone, may be due to the crystallization in the final extract and fibre powders caused by the fibres. Using this crystallization process to stabilize a bioactive extract in this way appears to be a novel process. (Source: International...

Rheological Properties of Chocolate Drink from Cupuassu

International Journal of Food Engineering — Tue, 12 Feb 2008 09:54:58 +0100

Flow behavior of chocolate drinks from Cupuassu (Theobroma grandiflorum, Sterculiaceae) from instantised and normal formulation, and enriched with calcium, were studied. Flow behavior was described using common rheological models (Newton, Power Law, and Bingham plastic). Experimental results, obtained at 25 oC and 40oC, fitted mostly the Ostwald and Bingham models, with R2 ≥ 0.997. The Newtonian model has 0.886 ≥ R2 ≥ 0.991. At 25 oC, as expected, viscosity of samples was higher and pseudoplasticity increased (n values were lower than 1). The spray-dryer process lead to differences of rheology of the ``chocolate'' milk drinks. The addition of microcrystalline cellulose plus calcium leads to a lower viscosity. (Source: International Journal of Food Engineering)

Control of Main Stored-Grain Insects with New Formulations of Entomopathogenic Fungi in Diatomaceous Earth Dusts

International Journal of Food Engineering — Mon, 21 Jan 2008 21:34:07 +0100

The present research is aimed at a formulation of the entomopathogenic fungi, Beauveria bassiana (Bal.) Vuillemin and Metarhizium anisopliae (Metch.) Sorokin, in two types of diatomaceous earth dusts, fossil shield and Silico-Sec, are then applied against the adults of three species of stored-grain insects: Sitophilus oryzae L., Rhyzopertha dominica Fab. and Tribolium castaneum Herbs. Effect of the treatment was assessed by comparing the mortality percentage of the adults of the three insect species exposed to the formulated fungi with that of the adults exposed to the unformulated fungi or the diatomaceous earth dusts or the undisturbed control. Results obtained from these exposures have indicated that treatment of the adults with the formulated fungi resulted in a significantly higher me...

Use of Natural Coagulants of Plant Origin in Production of Soycurd (Tofu)

International Journal of Food Engineering — Mon, 21 Jan 2008 03:02:42 +0100

Tofu - Soycurd, is one of the important non-fermented soybean products, which has been widely used in a variety of dishes by oriental people for many centuries. Normally in the preparation of Tofu, synthetic coagulants such as calcium sulphate, magnesium chloride, Glucono-δ-lactone, etc., are used. These coagulants are not readily available sometimes for use in the household and not available easily in the rural areas. Hence, an attempt was made to use natural coagulants of plant origin (Citrus lemon, Garcinia indica, Tamarindus indica, Averrhoa carambola, Averrhoa bilumbi, Phyllanthus distichus, Tamarindus indica flower extract, Hibiscus canabinus and Passiflora edulis) in preparation of Tofu. Yield, texture, proximate composition and sensory quality of Tofu prepared using natural coagul...

Effect of Conditioning on the Production of Inulinase by Kluyveromyces marxianus var. bulgaricus through Fed-Batch Fermentation

International Journal of Food Engineering — Thu, 17 Jan 2008 23:33:09 +0100

The effects of sucrose concentration, pH, temperature and aeration rate on the production of biomass and inulinase (2,1-beta-D-fructan fructanohydrolase, EC 3.2.1.7) were investigated using fed-batch fermentation by Kluyveromyces marxianus var. bulgaricus. The best sucrose concentration for enzyme activity was 10 g L-1, whereas activity was inhibited when the sucrose concentration was 20 g L-1. Enzyme activity was strongly influenced by pH of the culture. pH 5.0 was the most suitable for both enzyme activity and cell growth, achieving 98.04 U mL-1 and 14.05 g L-1, respectively, after 72 hours of cultivation. The highest production of inulinase and biomass was observed at temperatures of 25oC and 30oC, whereas a decrease in activity was observed at 35oC and 40oC. The best aeration rate was ...

Interaction of WPI and Xanthan in Microstructure and Rheological Properties of Protein Gels and O/W Emulsions

International Journal of Food Engineering — Tue, 08 Jan 2008 00:13:13 +0100

The effect of xanthan gum (0.05, 0.1, 0.15, 0.25% weight/volume) on the formation and rheology of whey protein isolate (WPI) gels has been investigated at neutral pH. The elastic modulus (G') from small deformation oscillation tests were used to compare the mechanical strength of protein gels. Low concentration of xanthan ( 0.05%, w/v), antagonist effect was observed. Gels containing higher amount of xanthan have disrupted protein aggregation and a decreased mechanical strength (lower in G'). The microstructure of WPI-stabilized emulsion containing xanthan gum has been investigated by confocal laser scanning microscopy, where xanthan was stained with Fluorescein 5(6)-isothiocyanate (FITC). Low xanthan concentration leads to depletion flocculation and increasing the xanthan concentration ca...

Rapid Determination of Intact Sardine Fat by NIRS Using Surface Interactance Fibre Probe

International Journal of Food Engineering — Fri, 21 Dec 2007 22:34:02 +0100

A near-infrared spectrometer equipped with surface interactance optical fiber probe (400-1100 nm) was used to determine the fat content in intact sardine Sardinops melanostictus which is considered one of the important fish species of world aquaculture as well as human food source. The fat contents were 2.64-25.52 % and fish weight ranges were between 45.23g and 133.76g. Partial least square regression was used to develop predictive equations for fat where two models (with and without multiplicative scatter correction known as MSC) showed relatively good performances with regression coefficients higher than 0.9 and errors below 1% on a fresh weight basis. Results showed that NIR interactance was a suitable non-destructive screening method for fat content in intact small pelagic fish like s...

Engineering Research to Improve Cassava Processing Technology

International Journal of Food Engineering — Wed, 19 Dec 2007 09:11:15 +0100

Cassava is an important food crop, and equipment development for processing it in the developing world requires more research as industrial processing of cassava is still limited. Research efforts made by local engineers need scientific improvement to meet the Millennium Development Goals (MDGs), aimed at poverty reduction over a stipulated period of time with globally defined measurable indicators of progress. The World Summit on Sustainable Development (WSSD), the Report of the Commission for Africa (popularly referred to as the Tony Blair Report), and the New Partnership for African Development (NEPAD) are targeted at re-positioning Africa in the world economy. The need for rapid cassava processing equipment and new equipment development to significantly improve stages involved in its p...

Forced Air Precooling Studies of Perishable Food Products

International Journal of Food Engineering — Tue, 11 Dec 2007 22:13:18 +0100

Food products of perishable nature are needed to be preserved from spoiling using the precooling technique. Precooling is the process of cooling fruits and vegetables as soon as possible after the harvest and prior to the transportation over long distances to a cold storage warehouse and marketing. Therefore, an experimental investigation has been carried out to study the temperature variation of different food products viz. apple, papaya and grape during the precooling process. Forced air cooling of food products was done by placing the particular food item inside a 4 m long rectangular air duct of 300 mm x 300 mm section. The temperature of cold air was in a range of 4-5 oC and the air velocity varied from 1.6 m/s to 4.1 m/s. The temperature of food product was measured at different radi...

Use of Response Surface Methodology to Study the Influence of Water Content and Air Pressure on Cake Batter Quality

International Journal of Food Engineering — Thu, 15 Nov 2007 21:24:01 +0100

The first aim of the study was to model the influence of water amount and air pressure on various batter properties using Response Surface Methodology. Batter quality was assessed through density, water content, colour, spreadability and fluorescence spectra. Quadratic models using two variables well represented spreading time, water content and final temperature, but they failed to fairly represent initial density, overrun and L*a*b* values. In addition, simplified models using a single variable also well represented the data: final density was modelled by a linear equation involving pressure, whereas initial density, water content and final temperature were modelled by a linear equation involving water amount. Spreading time was modelled using a quadratic equation using water amount. Exp...

The Development and Evaluation of a Four-roller Flour Mill with Parallelogram Configuration

International Journal of Food Engineering — Thu, 15 Nov 2007 21:23:58 +0100

A roller mill was designed and evaluated using four equal size cylindrical rollers with their centers on vertices of a parallelogram. The relative speeds and opposite direction of rotation of the rollers allowed the discharge of the materials on them, and splitting took place in between the first pair of corrugated rollers. The broken seeds were directed towards the second and third nips where adequate size reduction was accomplished consecutively by smooth rollers. The milled products were separated into three fractions: chaff, flour and size larger than flour. The chaff and the flour are collected at different outlets, while the particles with sizes larger than flour are blown back into the hopper for further reduction. The mill was evaluated using three grains: maize, beans and soy bean...

Some Physical and Mechanical Properties of Kiwifruit

International Journal of Food Engineering — Mon, 12 Nov 2007 21:56:26 +0100

In this paper, the physical properties such as length, width, thickness, geometric mean diameter, arithmetic mean diameter, mass, true volume, apparent volume, true density, bulk density, porosity, sphericity, surface area, shell ratio, aspect ratio, static coefficient of friction and mechanical characteristics namely firmness, hardness, adhesiveness, adhesive force and total positive area in puncture test were determined for kiwifruit of the Hayward variety. These properties are necessary in the design of the equipment for harvesting, processing and transportation, separating and packing. The results showed that the length, width, thickness, arithmetic mean diameter, geometric mean diameter, sphericity and aspect ratio of kiwifruit varied from 55.5 to 82.3 mm, 46.8 to 54.8 mm, 41.5 to 52....

Whey Protein Isolate-Starch System- A Critical Review

International Journal of Food Engineering — Tue, 06 Nov 2007 19:34:45 +0100

The two biopolymer proteins and polysaccharides are the key structural entities in food and pharmaceutical products. The design for liquid and semi-solid foods processing involves a complex and combined operations of heat transfer and fluid mechanics. These are strongly influenced by the thermal transitions and the rheological behavior of processing foods. In the present review a systematic discussion about the gelation, rheology of modified starches, and whey protein isolates are highlighted with an emphasis on various physico-chemical interactive effects. The studies are extended to protein and polysaccharide interactions and phase separations involved in the mixed system. Then the review has been made on protein-polysaccharide mixed gel systems citing few examples from the literature wi...

Contrasting Temperature Profile Development in Three Domestic Pressure Canners Operated without Venting

International Journal of Food Engineering — Fri, 02 Nov 2007 00:30:42 +0100

Effects during thermal processing of entrapped air on lethal effect were evaluated in three domestic canners with quart mason jars. Entrapped air volumes in ceramic-bead products were established with various fillings of water into a dry product matrix. Lethal effects were determined using thermocouples positioned near the bottom, middle, and top of the model product and others outside the jars. Two canners (All American and Mirro models) were continuously vented during the process while the third (National Presto) was not -- but was vented de facto until the lid lock moved up under the influence of escaping gases. Higher lethal effects were noted when least product-entrapped air was modeled. (Source: International Journal of Food Engineering)

Strength and Elastic Properties of Cassava Tuber

International Journal of Food Engineering — Wed, 31 Oct 2007 22:32:30 +0100

In this study, some engineering properties of cassava tuber samples were determined experimentally under five moisture content levels of 70 %, 65 %, 60%, 55 %, and 50 %wet basis. The properties measured were tensile strength, compressive strength and elasticity. Three experimental tools were designed and fabricated using spring balance, hose-clips, and 12Volts motor with reels and rope for the investigations. The IITA improved cassava variety TMS 4(2) 1425 was used in the experiments. Results of the tests indicated that all the properties measured were influenced by the moisture contents of the tuber. (Source: International Journal of Food Engineering)

Influence of Product-entrapped Air and Venting on Lethal Effect in Model Domestic Pressure Canner Studies

International Journal of Food Engineering — Fri, 26 Oct 2007 23:58:02 +0100

Effects of entrapped air during thermal processing on lethal effect were evaluated in three domestic canners with quart mason jars. Entrapped air volumes in ceramic-bead products were established with various fillings of water into a dry matrix. Alternate periods of venting included 5, 10, and 15 mins. Process pressure was monitored throughout each of the 54 runs. Venting times and lack of continuous venting demonstrated little impact. Higher lethal effects were noted when the least product-entrapped air was modeled. Differences were noted between pressure processes monitored by the dial gauge versus the calibrated weighted-devices with more variation of the dial gauge system due to the manual control basis. (Source: International Journal of Food Engineering)

Proximate Composition of the Apple Seed and Characterization of Its Oil

International Journal of Food Engineering — Thu, 25 Oct 2007 23:16:31 +0100

Apple seeds, a common byproduct of apple processing, have been examined for their overall proximate composition, fatty acid and amino acid composition of the lipid and protein components, respectively, as well as their key mineral constituents. Proximate analysis indicated that apple seeds are rich in oil content and protein ranging from 27.5 to 28% and 33.8 to 34.5% respectively, comparing favorably with oilseeds. GC analysis indicated high levels of linoleic acid (~49%) with the other dominant fatty acids being oleic, palmitic and stearic acids, ranging from ~39, 7 and 2% respectively. Amino acid analysis indicates that there are substantial amounts of sulfur containing amino acids in the apple seed. The apple seeds also contain significant amounts of phosphorus, potassium, magnesium, ca...

Study of the Influence of Product and Process Variables in the Salting and Post-salting Stages of PSE Thawed Hams

International Journal of Food Engineering — Thu, 25 Oct 2007 21:28:51 +0100

The use of thawed raw material is becoming more frequent in the cured ham processing industry. At the same time, the incidence of PSE meat in the raw material can be very important. The aim of this work was to characterise the salting and post-salting stages of PSE thawed hams, and to study the influence of process and product variables on the results obtained in industry. A deeper knowledge of this influence could help reduce the variability in salt concentration obtained in the process. Findings indicate a strong influence of pH, total ham weight, Lean/Fat ratio and the contact area of the hams in the salting stage, while the post-salting time was the variable that exerted the greatest influence on the salt and water distribution inside the hams during this stage. (Source: International ...

Texture Profile Analysis of Cooked Sun Dried Nuggets (Bori) Prepared with Different Levels of Moisture Content and Percent Air Incorporation in Its Batter

International Journal of Food Engineering — Thu, 25 Oct 2007 21:28:48 +0100

In this paper the texture profile analysis for the cooked Bori nuggets (traditional Indian food) prepared from black gram batter having different initial moisture content of 62 to 72% (wb) and air incorporation of 14.14 to 18.12% (v/v) is discussed. The initial moisture content and the volume of air incorporation into the batter had significant effect at either 5% or 1% level of significance on the springiness, chewiness, hardness, cohesiveness and gumminess of the cooked nuggets. The optimum initial moisture content of 65.10 to 67.15% (wb) in the batter and air incorporation of 15.91 to 17.23% (v/v) in it are recommended in obtaining the maximum and minimum levels of the response quality parameters. The optimum values of these response parameters would be 0.453, 12.22, 60.31 N, 0.36 and 2...

Physicochemical Properties of the Josapine Variety of Pineapple Fruit

International Journal of Food Engineering — Wed, 24 Oct 2007 03:06:09 +0100

Several parameters related to the physicochemical properties of Josapine pineapple juice, such as moisture content, total soluble solids (TSS), pH, color, water activity, freezing point, sugar content and acidity, were evaluated over a week of ambient storage at 25oC and 52% RH. The results indicated that Josapine pineapples take about 11 days to progress from maturity stage 1 to stage 7. The moisture content of fruit increased from 93.5% wb to 95.1% wb over the 11 days period. Analysis on the color of the juice showed the color space coordinate parameter b varies between 9.11 to 15.8, parameter a increased from -3.33 to -3.68 and the 'L' value decreased from 39.46 to 38.7 at the initial ripening stage but increased to 40.9 in the later stages. The TSS increased at the early ripening stage...

Dynamic Effect in High Pressure Microbe Inactivation

International Journal of Food Engineering — Thu, 18 Oct 2007 22:28:25 +0100

This paper proposes the liquid inertia coupled to the dynamics of micro bubbles as one of the mechanisms for microbe inactivation by high pressures. Liquid inertia can cause a stable bubble to grow unlimited through a pressurization followed by a sudden pressure release. In cases when the vapor pressure is too low to allow unlimited bubble growth, the liquid inertia leads to the hammering effect associated with nonlinear bubble oscillations, a purely mechanical effect that may be responsible for microbe inactivation. (Source: International Journal of Food Engineering)

The Changes in the Lipid Composition of Mung Bean Seeds as Affected by Processing Methods

International Journal of Food Engineering — Mon, 24 Sep 2007 23:49:54 +0100

This study was conducted to assess in detail the possible effects of some technological processes such as soaking, germination, cooking, soaking + cooking, and germination + cooking on the lipid composition of mung bean seeds of Giza 1 variety. TLC analysis of mung bean lipids showed that the phospholipids and triglycerides recorded the highest percentage among lipid fractions (32.26 and 30.10%), while the 1,3 diglycerides constituted the least percentage (2.80%) in mung bean seeds. The soaking, germination and cooking processes caused a decrease in the phospholipids, triglycerides and hydrocarbons accompanied with an increase in monoglycerides, 1,2-(2,3)-diglycerides, sterols and free fatty acids. Eleven fractions were separated from phospholipids class of the studied samples; seven of th...