bluuebunny/crossref_metadata_2025_split huggingface dataset:
ELECTRODIALYSIS of WHEY PERMEATES and RETENTATES OBTAINED BY ULTRAFILTRATION
Authors: PÉREZ A. , ANDRÉS L.J. , ÁLVAREZ R. , COCA J. , HILL C.G. 
Published: February 2007

Demineralization of a synthetic UF‐whey permeate and a reconstituted UF‐whey retentate was studied in a laboratory electrodialysis (ED) unit.Data on conductivity, ionic concentration, ash removal, electrical efficiency and energy consumption are reported at three temperatures (20, 35 and 45C) and three flow rates (100, 160 and 230 l/h). the extent of deashing is lower for the UF‐whey retentate than for the UF‐whey permeate as a result of concentration polarization, which results in an increase of the boundary layer thickness, due to deposition of proteins and salts on the membranes.
THERMAL INACTIVATION of PECTINESTERASE IN PAPAYA PULP (pH 3.8)
Authors: MAGALHÃES M.M. DOS A. , TOSELLO R.M. , DE MASSAGUER P.R. 
Published: February 2007

In order to establish the thermal process required by acified papaya pulp (pH 3.8) var “formosa”, a study was carried out on the kinetics of thermal inactivation of the heat resistant enzymes present in the pulp. Since no peroxidase activity was detected, the study was focused on pectinesterase.The heat inactivation curves at 75, 77 and 80C showed a change in slope indicating the presence of two different portions of the enzyme, one heat labile and the other heat resistant. the decimal reduction times (D value) of pectinesterase were 0.8, 0.3 and 0.2 min for the heat labile portion and for the heat resistant portion 16.7, 7.2 and 3.7 min, respectively.The temperature‐dependency factor for the heat labile portion was 9.2C and 7.8C for the thermostable portion, while the activation energies were 258.3 and 304.4 Kj/mol. These values were within the range of 167.5–418.7 Kj/mol reported in the literature for the thermal inactivation of enzymes. Thermal destruction studies with Clostridium pasteurianum, conducted at the same temperatures used for the inactivation of the enzyme, showed that the heat resistant portion of pectinesterase presented greater thermal resistance and should be used as target for the establishment of the required process.
ELECTRIC FIELD EFFECTS ON THE THERMAL CONDUCTIVITY OF MILK CHOCOLATE DETERMINED USING THE “MIRROR IMAGE METHOD”
Authors: DAUBERT C.R. , STEFFE J.F. , LLOYD J.R. 
Published: February 2007

ABSTRACTElectrorheological fluids exhibit changes in flow properties when exposed to an electric field. Generally, these fluids display an increase in apparent viscosity and a greater yield stress in the presence of a voltage. Another attribute of some electrorheological fluids is the ability to enhance heat transfer, allowing for greater control over heating and cooling unit operations. This paper examined the effects of an applied voltage on the thermal conductivity of molten milk chocolate, a material known to be an electrorheological fluid. The method used to measure the thermal property was based on the “mirror image’ concept. In this technique, identical disks sandwich a heat source providing a constant heat flux directed evenly between the two sides. Knowing the heat flux and the boundary temperatures of the sample gap, an analytical solution was used to calculate the thermal conductivity and specific heat. An applied electric field of up to 450 V mm−1 at 60 Hz was found to have no significant effect on the heat transfer properties of milk chocolate. The thermal conductivity was found to have an average value of 0.163 W m−1 K−1 over a temperature range varying from 25 to 60C. The measurement technique, however, proved to be a rapid method for determining thermal properties that may be useful in investigating other liquid foods.
PHYSICAL AND COOKING PROPERTIES OF MICRONIZED LENTILS
Authors: CENKOWSKI STEFAN , SOSULSKI FRANK W. 
Published: February 2007

ABSTRACTThe potential for reducing the cooking time of lentils by micronization was studied. The effect of infrared heat and initial seed moisture on the internal temperature of lentil seeds was monitored up to the stage of seed browning. The seed physical properties, water uptake by seeds, cooking time and starch properties were determined. The cooking time was shortened from 30 min for the control seeds to 15 min for lentils adjusted to 25.8% wb moisture content and micronized for 55s to 18.0% wb moisture. Micronization was effective in gelatinizing and solubilizing 45 to 65% of the starch in the lentil seed, depending on the initial seed moisture content.
NONLINEAR PREDICTIVE OPTIMAL CONTROL OF A BATCH REFRIGERATION PROCESS
Authors: TRELEA IOAN‐CRISTIAN , ALVAREZ GRACIELA , TRYSTRAM GILLES 
Published: February 2007

ABSTRACTA predictive optimal control algorithm for a fruit refrigeration process is described. The future inlet air temperature profile is optimized on line, taking into account the most recent process measurements, and thus introducing feedback. The optimality criterion is directly based on economic costs. Technological and product quality constraints are included. The future control profile optimization requires long term predictions of process variables evolution, achieved using a physical model of the plant. The model is adjusted on line in order to account for unmeasured disturbances and poorly known product properties. Both the optimality criterion and the plant model are nonlinear. The approach is experimentally validated on a pilot scale refrigeration plant. Economic benefits from using an optimal, rather than a traditional constant temperature profile are discussed, revealing the importance of the process configuration. Robustness of the control algorithm with respect to modeling errors, measured and unmeasured disturbances, and temporary plant failures is demonstrated.
INFUSION OF CITRUS FRUIT PEEL BY LOW‐PRESSURE FLUID INJECTION USING A SELF‐SEALING NOZZLE
Authors: PAO STEVEN , PETRACEK PETER D. 
Published: February 2007

ABSTRACTRemoval of citrus peel is facilitated by infusion of water into the peel. A low‐pressure fluid injection (LPFI) technique was developed to improve infusion efficacy. Water under low pressure (340 to 1700 mbar) was forced through an opening formed near the equator of the fruit. The water spread uniformly throughout the albedo before exiting through an additional hole made on the opposite side of the fruit. Increasing pressure and flow rate reduced injection time, but excessive levels created high internal pressures that occasionally caused peels to rupture. A rubber bulb with an orifice at the tip created a nozzle that produced a water‐tight interface with the fruit during injection.
DESIGN AND SELECTION OF PROCESSING CONDITIONS OF A PILOT SCALE CONTACTOR FOR CONTINUOUS OSMOTIC DEHYDRATION OF CARROTS
Authors: QI H. , LeMAGUER M. , SHARMA S.K. 
Published: February 2007

ABSTRACTA pilot‐scale belt type osmotic contactor was designed and installed in a continuous osmotic dehydration process to obtain maximum water removal from fruits and vegetables with a minimum contact time. The carrot was chosen as a representative vegetable and a ternary mixture of sucrose/sodium chloride/water with total solids concentration of about 50 to 55% was chosen for the osmotic solution. The experimental results showed that the optimum condition was found to require a 44% sucrose/7% sodium chloride aqueous solution with 16 min of contact time which gave a water loss of 26% and a highest ratio of water loss over solids gain (about 9) among different treatments. It is concluded that the continuous type of contactor can have potential applications in the food industry.
RESIDENCE TIME DISTRIBUTION (RTD) AND GOODNESS OF MIXING (GM) DURING CO2‐INJECTION IN TWIN‐SCREW EXTRUSION PART I: RTD STUDIES
Authors: SINGH BHAJMOHAN , RIZVI SYED S.H. 
Published: February 2007

ABSTRACT The residence‐time distribution (RTD) studies are needed to characterize mixing conditions, flow patterns, and the extent of conversions and reactions of the biopolymers in any plasticating or cooking extruder. For the supercritical fluid extrusion process (SCFX), mixing of the fluid and starch‐based biopolymers is an important step affecting cell nucleation and growth. RTD was studied in the mixing zone of the extruder, where CO2 and gelatinized starch are brought together. Three levels of each of the process variables (screw speed and CO2 injection pressure) were investigated, using specially designed apparatus for color‐dye injection, and a die‐restrictor to change the pressure profile and hold up volume in the extruder. Control RTD plots were for no CO2 injection conditions at the same pressure, and the RTD of the full extruder section. Experimental RTDs were evaluated by: (1) the Wolf‐White model, (2) a cascade of continuously stirred reactors (CSTR) model and (3) a model based on plug‐flow in series with cascade of CSTRs. The last approach was most successful in capturing all aspects of the observed RTD curves including their tails. Injection of CO2 at the highest pressure (110.3 bar) increased the RTD compared to no CO2‐injection conditions. There were significant differences in the plug flow component of the RTD as well as differences in average residence time as a function of both screw speed and CO2 injection pressure conditions.
SIZE AND SHAPE EFFECT ON NONUNIFORMITY OF TEMPERATURE AND MOISTURE DISTRIBUTIONS IN MICROWAVE HEATED FOOD MATERIALS: PART II EXPERIMENTAL VALIDATION
Authors: VILAYANNUR R.S. , PURI V.M. , ANANTHESWARAN R.C. 
Published: February 2007

ABSTRACT Experiments were conducted to determine temperature and moisture distributions in brick‐shaped, cylinder‐shaped and hexagonal prism‐shaped products. Center heating for cylindrical shapes, corner heating for brick‐shapes and surface drying in all the shapes considered were predicted by the finite element model (FEM) and were observed in the experimental data. The slow rate of heating in the case of hexagonal‐prism shaped products predicted by the FEM was validated by the experimental study. The FEM calculated moisture distributions matched the experimentally measured values closely for brick (maximum % error = 9.3% and standard error = 0.9%), cylinder (6.9% and 0.6%) and hexagonal prism (1.5% and 0.15) shaped products. The FEM calculated temperature distributions and experimentally measured values were closer in the case of brick‐shaped products (maximum % error = 24.7% and standard error = 4.3C) and cylinder‐shaped products (22.0% and 2.8C) when compared to hexagonal prism‐shaped products (57.3% and 3.3C).
DIFFUSION OF OXYGEN INTO A PACKAGED PRODUCT (APPLE JUICE) WITH SIMULTANEOUS OXIDATION OF ASCORBIC ACID
Authors: KIM J.N. , HARTE B.R. , CASH J.N. , BURGESS G. 
Published: February 2007

ABSTRACTOne and three dimensional mathematical models to predict loss of quality in packaged apple juice were developed. The models were based on the mass transfer of oxygen through the wall of the package and into the apple juice, and mass transfer of ascorbic acid within the apple juice with simultaneous oxidation of ascorbic acid in the packaged apple juice. Computer programs were developed to solve the mathematical model, using the finite difference method. Concentration of the ascorbic acid in the apple juice was checked using high performance liquid chromatography. Mathematical models and computer programs were successfully validated by experimentation. The model can predict the loss of ascorbic acid in apple juice up to 50% ascorbic acid remaining. The three dimensional mathematical model is valid on block type geometric packages. The mathematical model and computer program can be modified for other geometric shapes, product morphology, and oxygen diffusion, and for other forms of product oxidation.
OHMIC HEATING OF SOLID‐LIQUID MIXTURES: A COMPARISON OF MATHEMATICAL MODELS UNDER WORST‐CASE HEATING CONDITIONS1
Authors: SASTRY SUDHIR K. , SALENGKE S. 
Published: February 2007

ABSTRACTA critical issue in the modeling of ohmic heating of solid‐liquid mixtures is the understanding of worst‐case scenarios, and in particular, the reliability of mathematical models under such conditions. This study involves examination of two alternative published formulations, one involving the use of circuit theory and a well‐mixed fluid assumption, against another formulation, involving the solution to Laplace's equation, but without convective effects. As expected, the models (and an analytical solution) yield identical results under situations where solid and fluid electrical conductivity are equal. However, when the solid is of lower electrical conductivity than the fluid, the Circuit Analogy, Mixed Fluid (CAMF) approach is shown to be more conservative than the Laplace Equation, No Convection (LENC) approach. This prediction is borne out by experimental studies, which confirm that the worst‐case scenario in ohmic heating is not necessarily associated with a stationary fluid situation. Under the less likely conditions where the solid is more conductive than the fluid, the LENC approach is more conservative than the CAMF approach. Models are also compared with respect to other features, such as practicality of use, and computational cost.
PROBABILISTIC SIMULATION OF BATCH TRAY DRYING USING MARKOV CHAINS AND THE MONTE CARLO TECHNIQUE
Authors: CRONIN KEVIN 
Published: February 2007

ABSTRACTThe objective in food dehydration is to dry the product to a specified uniform moisture content. In practice, a distribution in final moisture content is unavoidable, arising from the intrinsic variability of food properties and the probabilistic nature of the food drying process. A methodology is outlined whereby the inherent stochastic dynamics of batch tray dehydration in cabinet or tunnel dryers can be modeled efficiently using Markov chains. By simulating the drying process with the model, the progressive transformation of the moisture distribution of the trays throughout the drying cycle can be quantified. Output from the model is validated with experimental drying results to test its accuracy. In addition the output of the Markov approach is compared with that of an equivalent Monte Carlo simulation model to provide inter‐model comparisons. Markov analysis can predict the variation in final moisture content and thus has the potential to help maximize the value of the dried product.
A METHOD TO CHARACTERIZE ELECTRODE CORROSION DURING OHMIC HEATING
Authors: ZHAO YANYUN , KOLBE EDWARD , FLUGSTAD BEN 
Published: February 2007

ABSTRACTA method was developed to characterize visual electrode corrosion during ohmic heating of a model system. Stainless steel 304 electrodes were energized in a 2% salt solution at room temperature of 24±1C for 10 min. The effects of Alternating Current (AC) electrical frequency and current density were examined in a frequency range of 55 to 5000 Hz and current density range of 1200 to 3500 A/m2. The ratio of colorimeter values of lightness (L)/yellowness (b) was used to quantify the degree of visual corrosion. Corrosion was most serious at low AC electrical frequencies of 55, 100, 200 Hz and at high current density of 3500 A/m2. At AC electrical frequency values above 5000Hz, corrosion reduced dramatically even as current density was increased to 3500 A/m2 and heating time extended to 1–1/2 h.
NEW METHOD FOR DETERMINING INTERNAL TEMPERATURE OF COOKING MEAT VIA NMR SPECTROSCOPY
Authors: WALTON JEFFREY H. , McCARTHY MICHAEL J. 
Published: February 2007

ABSTRACTNMR spectroscopy is used to determine fat content and internal temperature of hamburger, pork sausage, and various cuts of chicken during cooking. The temperature is determined by the frequency difference of the water and fat lines within the NMR spectrum. This method is more accurate than the absolute measurement of either peak alone. Furthermore, because the measurement relies on a frequency difference, precise control of the magnetic field is unnecessary. The hamburger and sausage data indicate an accuracy of ± 1C. The temperature accuracy for chicken is ± 5C. The difference in accuracy is due to the lower fat content of chicken. Chicken bone marrow, however, has a high fat content which could be used to measure its temperature. The speed and accuracy of this technique admits the possibility of using NMR spectroscopy on the process line to determine when these cuts of meat are sufficiently cooked and thus safe.
CRISPBREAD QUALITY EVALUATION BASED ON FUSION OF INFORMATION FROM THE SENSOR ANALOGIES TO THE HUMAN OLFACTORY, AUDITORY AND TACTILE SENSES
Authors: WINQUIST F. , WIDE P. , EKLÖV T. , HJORT C. , LUNDSTRÖM I. 
Published: February 2007

ABSTRACTAppreciation of food is based on the perception all five human senses; vision, tactile, auditory, taste and olfaction. Sensory integration of chewing resistance, melting properties, crisp sound etc. will give a further perception of the food, which is called the mouth feel. In this report, a model experiment performed on crispbread is described, which was based on information fusion from human sense analogies of olfaction, auditory and tactile. Five samples of crispbread with various hardness and flour composition were placed in a special “crush chamber”. While crushed, information corresponding to three senses could be obtained – auditory by a microphone, tactile by a force sensor and smell by leading gases from the crushed material to a gas sensor array. To evaluate the information obtained, multivariate pattern recognition methods, i.e. principal component analysis and artificial neural nets were used to search for structure and correlation in the data. It was shown that by using only the auditory information, the samples could not be separated. The tactile information alone could separate three samples, and the smell information one sample. By combining all sense analogues, all five samples could be separated.
THERMODYNAMICS OF MOISTURE SORPTION IN WINGED BEAN SEED AND GARI
Authors: FASINA O.O. , AJIBOLA O.O. , TYLER R.T. 
Published: February 2007

ABSTRACTExperimental data on sorption isotherms of gari and winged bean seeds were used to determine their thermodynamic functions (heat of vaporization, spreading pressure, net integral enthalpy and entropy). The heat of vaporization of both products reduced with increase in moisture content and approached that of saturated water at moisture contents of about 15%. Within the moisture content range of 2.0 and 18.0%, the net integral enthalpy and net integral entropy of gari were respectively higher and lower than those of winged bean seeds. The maximum net integral enthalpy for gari was 556 kJ/kg and was 335 kJ/kg for winged bean seeds. The difference in the values of the thermodynamic functions were attributed to the higher amount of oil/fat in winged bean seeds and the presence of gelatinized starch in gari.
DIELECTRIC PROPERTIES OF SHRIMP RELATED TO MICROWAVE FREQUENCIES: FROM FROZEN TO COOKED STAGES
Authors: TANAKA F. , MALLIKARJUNAN P. , HUNG Y.‐C. 
Published: February 2007

ABSTRACTDielectric properties of shrimp (Penaeus sp.) were measured at frequencies between 0.3 and 3 GHz from ‐25 to 70C by using a network analyzer. The relationship between dielectric properties and temperature was determined at 915 MHz and 2450 MHz. Below the freezing point, the dielectric constant (ɛ′) and dielectric loss factor (ɛ″) increased rapidly with increasing temperature as ratio of frozen water in shrimp was decreasing. Above the freezing point, the dielectric constant (ɛ′) decreased as frequency and temperature increased at both frequencies. The dielectric loss factor (ɛ″) did not change significantly with temperature. The relationships between penetration depth and temperature at both frequencies were evaluated from the experimental data.
MODELING OF TEMPERATURE PROFILES UNDER CONTINUOUS TUBE‐FLOW MICROWAVE AND STEAM HEATING CONDITIONS
Authors: BAIL A. Le , KOUTCHMA T. , RAMASWAMY H.S. 
Published: February 2007

ABSTRACTMathematical models were developed based on perfectly mixed flow (PMF), piston flow with heat diffusion (PFHD) and laminar flow (LF) approaches to predict liquid temperature history under continuous tube‐flow microwave and steam heating conditions. Two helical glass coils placed inside domestic microwave ovens (one coil in each of the two 700 W capacity ovens) or in a steam cabinet were used for heating and a spiral condenser at the exit was used for cooling. Transient and steady state mean temperatures of the fluid were experimentally measured at the exit and were compared with predictions from the mathematical models for both systems. The residence time, velocity distribution as well as temperature profiles, along the radius and the length of the tubes, were computed using the models. The PFHD and the LF models better described temperature profiles during the initial transient period, while the PMF model shovsed a better agreement with experimental data during steady staie conditions. The occurrence of secondary turbulence in the helical coil (associated with high Dean numbers) was believed to be responsible for reducing the radial temperature gradients and achieving close to “perfectly mixed piston flow” situation. A relatively larger temperature gradient across the radius was observed under microwave heating conditions than under steam heating conditions. The time‐temperature effects were integrated to predict the lethality at selected temperatures and flow rates for both continuous‐flow thermal processing.
CHARACTERIZATION OF FOOD SURFACES USING SCALE‐SENSITIVE FRACTAL ANALYSIS
Authors: PEDRESCHI FRANCO , AGUILERA JOSÉ M. , BROWN CHRISTOPHER A. 
Published: February 2007

ABSTRACT Length‐scale and area‐scale analyses, two of the scale‐sensitive fractal analyses performed by the software Surfrax
http://www.surfract.com, were used to study food surfaces measured with a scanning laser microscope (SLM). The SLM measures surfaces, or textures (i.e., acquires topographical data as a collection of heights as a function of position), at a spatial and vertical resolution of 25 μm. The measured textures are analyzed by using linear and areal tiling (length‐scale and area‐scale analysis) and by conventional statistical analyses. Area‐scale and length‐scale fractal complexities (Lsfc and Asfc) and the smooth‐rough crossover (SRC) are derived from the scale‐sensitive fractal analyses. Both measures proved adequate to quantify and differentiate surfaces of foods (e.g., chocolate and a slice of bread), which were smooth or porous to the naked eye. Surfaces generated after frying of potato products (e.g., potato chips and French fries) had similar values of Asfc and SRC, and larger (implying more complex and rougher surfaces) than those of the raw potato. Variability of surface texture characterization parameters as a function of the size of the measured region was used in selecting the size of the measured regions for further analysis. The length‐scale method of profile analysis (also called the Richardson or compass method) was useful in determining the directionality or lay of the anisotropic texture on food surfaces.
EFFECTS OF THERMAL AND ELECTROTHERMAL PRETREATMENTS ON HOT AIR DRYING RATE OF VEGETABLE TISSUE
Authors: WANG WEI‐CHI , SASTRY SUDHIR K. 
Published: February 2007

ABSTRACTCylindrical samples of carrot, potato and yam were dried in a hot‐air dehydrator after preheating to 50C or 80C by three different heating methods (conventional, microwave and ohmic). The results showed that enhancement of drying rate increased with pretreatment temperature. Ohmic pretreatment increased the drying rate more than conventional and microwave heating. Desorption isotherms showed that in the low aw range, desorption data of preheated and raw materials were similar. However, the isotherms of preheated samples shifted when aw was high, which indicated that thermal pretreatments altered the structure, and apparently, the water distribution within these materials. For all samples, ohmic pretreatment showed stronger influences on isotherms than microwave heating, while the pretreatment effect of conventional heating was only observed for potato tissue.