bluuebunny/crossref_metadata_2025 huggingface dataset:
SPECIFIC HEAT of DEHYDRATED PULPS of FRUITS
Authors: ALVARADO JUAN DE DIOS
Published: February 2007

Specific heat of dehydrated pulps, which were obtained from 31 different fruits at several moisture contents, was determined by the indirect mixing method. Data are reported for each fruit. They confirm the application of linear functions, especially at moisture contents above 50%. an exponential regression equation for calculation of specific heat in the whole range of moisture content was established using all the values.
DISTRIBUTION of HEAT TRANSFER RATE and LETHALITY IN A SINGLE BASKET WATER CASCADE RETORT
Authors: CAMPBELL S. , RAMASWAMY H.S.
Published: February 2007

Temperature and heat distribution studies were carried out in a single basket horizontal water cascading retort at two temperatures and two air over‐pressure levels under fully loaded operating conditions. Various heat transfer parameters (heating and cooling rate indices, fh and fc), lag factors (jch and jcc) and process lethality (Fo) were used as indicators of the retort performance. Time‐temperature data gathered from 24 LexanTM transducers were used for calculation of the heating and cooling rate indices as well as lethality. There were significant variations in the temperature distribution and heat transfer parameters at the different tray levels; however, these variations did not contribute to large variations in the accumulated overall process lethality.
THE FLUID MECHANICS of COOKIE DOUGH EXTRUDERS
Authors: LEVINE LEON , BOEHMER ED
Published: February 2007

A model of the fluid mechanics of two roll cookie dough extruders, such as used for wire cut and rout cookies, is presented. the model uses the lubrication approximation to obtain a first estimate for the predictive equations for extruder capacity, power consumption, total shear strain, and forces developed by the rolls. These equations are used to understand the importance of various design and operational parameters.
PREDICTION of MASS‐AVERAGE and SURFACE TEMPERATURES, and the TEMPERATURE PROFILES AT the COMPLETION of FREEZING FOR SHAPES INVOLVING ONE‐DIMENSIONAL HEAT TRANSFER
Authors: ILICALI COŞKAN , ENGEZ SEMIH TEVFIK , ÇETIN METIN
Published: February 2007

A model for predicting the temperature profiles of simple‐shaped foodstuffs at the end of freezing was developed. It was shown that with appropriate selection of effective thermal diffusivity and initial temperature data, the standard solution of the unidimensional unsteady state heat conduction equation can be used in predicting the average and surface temperatures of infinite slabs at the end of freezing operation. For the calculation of average and surface temperatures in infinite cylinders and spheres, unsteady state solutions were corrected by an empirical factor that was derived from temperature profiles predicted by an accurate finite difference scheme. the temperature profiles calculated from the proposed model were compared with the predicted results obtained from a numerical model. Mean absolute errors between the predictions of the proposed model and the numerical model were 0.54C and 0.46C for average and surface temperatures, respectively.
REVERSE OSMOSIS TRANSPORT and MODULE ANALYSIS FOR GREEN TEA JUICE CONCENTRATION
Authors: ZHANG SHI QIU , FOUDA A.E. , MATSUURA T. , CHAN KAM
Published: February 2007

Reverse osmosis experiments were performed to concentrate the green tea juice, and the experimental data was analyzed by using a set of transport equations together with osmotic pressure and density data of the green tea juice. the transport parameters obtained numerically by the above analytical procedure were then used to calculate several dimensionless quantities that can characterize a reverse osmosis module. an example of module design calculation was attempted using the dimensionless parameters so obtained. It has been found that an increase in operating pressure reduces the module length significantly when the feed tea juice concentration is high. an increase of the mass transfer coefficient on the high pressure side of the membrane has the same effect.
MODELLING of TIME‐TEMPERATURE EFFECTS ON BACTERIA POPULATIONS DURING COOLING of CHEDDAR CHEESE BLOCKS1
Authors: GRAZER C.L. , SIMPSON R. , RONCAGLIOLO S. , BODYFELT F.W. , TORRES J.A.
Published: February 2007

Differences in cooling rate of Cheddar cheese from pressing (35C) to aging temperature (3.5–12C) has been reported to be responsible for flavor variation within a production lot. During aging, starter and nonstarter bacteria contribute extensively to flavor quality. Temperature effects on these bacteria were quantified using cheese from a local processor. At day 1, starter counts were 8 × 107 cfu/g but as aging continued, starter counts decreased and non‐starters became dominant. At 35C, starter counts reached 3 × 106 cfu/g by day 3 and were below 106 cfu/g by day 5. At 25, 20, 15 and 12C, starter bacteria were below 106 cfu/g by day 10, 20, 24 and 40, respectively. Nonstarter counts, initially at 104 cfu/g, reached = 108 cfu/g at increasingly shorter times with higher temperatures. Kinetic analysis of growth in cheese and in a liquid medium suggested the possibility of diffusion growth limitations in cheese. Computer simulations for the growth of nonstarters suggests the individual cooling of small blocks (18 kg) would reduce the contribution of nonstarter counts to Cheddar cheese aging.
COLLECTION of ACCURATE EXPERIMENTAL DATA FOR TESTING the PERFORMANCE of SIMPLE METHODS FOR FOOD FREEZING TIME PREDICTION
Authors: CLELAND D.J. , CLELAND A.C. , JONES R.S.
Published: February 2007

Objective testing of the accuracy of food freezing time prediction formulae requires experimental data to be of high quality. It is shown that there are shortcomings in commonly used experimental methods, particularly relating to minimizing heat transfer in all but the required dimensions in experiments with the slab and infinite cylinder shapes, in maintaining uniformity of surface heat transfer coefficients across a sample, and in measurement of surface heat transfer coefficients. Broad guidelines to ensure that the errors introduced by experimental techniques are negligibly small are proposed. Major published experimental data sets are compared to these guidelines and comments made on their likely accuracy.
CONVECTIVE HEAT TRANSFER COEFFICIENT FOR CUBIC PARTICLES IN CONTINUOUS TUBE FLOW USING the MOVING THERMOCOUPLE METHOD1
Authors: ZITOUN KHALED B. , SASTRY SUDHIR K.
Published: February 2007

The convective heat transfer coefficient, hfp, between fluid and cubic particles was investigated with respect to flow rate, viscosity, and particle to tube dimension ratio using a moving thermocouple method. This study was conducted for a single particle. the determined values of hfp ranged from 199 W/m2C and 749 W/m2C. Results indicate that an increase in viscosity or dimension ratio decreased hfp values. In contrast, an increase in flow rate increased values of hfp. the effect of particle to tube dimension ratio was the opposite of those in previous studies by this method and appears to be due to differences inflow regime (laminar in this study, as compared to fully developed turbulence in previous work). A dimensionless correlation developed to relate Nusselt number to generalized Reynolds and Prandtl numbers, ratio of particle characteristic length and diameter of the tube, had an r2 value of 0.94.
MICROWAVE and CONVECTIVE DRYING of POTATO SLICES
Authors: BOURAOUI M. , RICHARD P. , DURANCE T.
Published: February 2007

Potato slices were dried using microwave drying, combined microwave and convective drying, and convective drying. Rehydration kinetics were also studied. Drying rates of the different drying methods were determined and microwave drying was compared with convective drying. Microwave drying has a potential for producing better quality dried products while considerably reducing drying duration (i.e., 10 min vs. 10 h). Effective moisture diffusivity profiles were calculated using Fick's diffusion model in one dimension. Statistical analysis showed diffusivity to increase with increasing internal temperature but to decrease (in microwave drying) with increasing moisture content, with high correlation (R2≥ 0.973).
DETERMINATION of HEAT TRANSFER COEFFICIENTS DURING DRYING of FOODSTUFFS
Authors: RATTI C. , CRAPISTE G.H.
Published: February 2007

Heat transfer coefficients during drying of foods were evaluated from drying data and heat and mass balances. Experimental drying curves for slices and cylinders of potato, apple and carrot were obtained in a laboratory dryer under different drying conditions. the specific heat of the foodstuffs was measured as a function of water content and modelled through a linear relationship. Experimental heat transfer coefficients were correlated by the dimensionless expression NuD= 0.249 ReD0.64 and compared with predictions of different equations.
PARTICLE CONCENTRATION INFLUENCE ON LIQUID RESIDENCE TIME DISTRIBUTIONS IN A MODEL ASEPTIC PROCESSING SYSTEM1
Authors: LEE JUN H. , SINGH RAKESH K. , LINEBACK D. SCOTT
Published: February 2007

Residence time distributions (RTDs) of water as influenced by particle concentration and mutator speed (SSHE only) were investigated in a holding tube and a horizontal scraped surface heat exchanger (SSHE). Liquid mean residence times (LMRTs) were not significantly influenced by particle concentrations up to 30% in the holding tube. Variance, on the other hand, was significantly higher without particle loading, indicating a broader distribution. About 20% particle loading significantly reduced the LMRTs regardless of the mutator speed. In addition, an increase in the mutator speed significantly increased the variance regardless of the particle concentration, indicating a broader distribution. the variance in SSHE was not significantly influenced by the particle concentration, unlike the holding tube. the LMRTs calculated from volumetric flow rates were lower than those from pulse input experiments for both holding tube and SSHE.
ADSORPTION of BILE ACIDS ON CEREAL TYPE FOOD FIBERS
Authors: HUANG CHAO‐MING , DURAL NILUFER H.
Published: February 2007

A study involving measurement and analysis of adsorption of common bile acids, namely cholic, deoxycholic, and lithocholic acids, on cereal type dietary fibers was conducted. the selected food fibers were oat fiber, rice fiber, barley fiber, corn bran, and wheat bran, which are all extensively used in processed foods. the adsorption data were measured at 37C and 25C, which correspond to approximate human body and room temperatures. Influence of particle size reduction, due to grinding, on a fiber's bile acid binding capacity was examined by using macro size (35–60 mesh) and micro size (100–300 mesh) fibers as adsorbents. the investigation also included the effects of medium pH and the chemical composition. the experimental data were correlated with the Langmuir and the Freundlich isotherms in order to utilize the data in future predictions and simulations.

It was found that the particle size reduction, accompanied by surface area increase, has a significant influence on the adsorption capacity of the fiber. Macro size fibers adsorbed the same bile acid with the following trend: oat > barley > rice > wheat > corn; while micro size fibers followed a somewhat different trend: rice > barley > oat > wheat > corn. This was due to the surface area change after grinding, and a positive correlation between the surface area and the adsorption capacity was observed in each case. the adsorption was favored by acid pH surroundings, and it was positively correlated with the hydrophobicity of the bile acid. were adsorbed on the same fiber with the following trend: lithocholic acid > deoxycholic acid > cholic acid. Fibers adsorbed more bile acid at 25C than they did at 37C. However, the increase in the uptake capacities were not very signipcant.
DRAG ON MULTIPLE SPHERE ASSEMBLIES SUSPENDED IN NON‐NEWTONIAN TUBE FLOW
Authors: SANDEEP K.P. , ZURITZ CARLOS A.
Published: February 2007

The drag forces experienced by single and multiple sphere assemblies suspended in non‐Newtonian tube‐flow were investigated under different levels of fluid viscosity of aqueous CMC solutions (m=2.0 to 21.1 Pa‐sn and n=0.73 to 0.82), flow rate (0.02 to 0.86 kg/s) and particle concentrations (1.53 to 11.01% on a volume basis). It was found that an increase in particle concentration resulted in an increase in drag force experienced by each sphere in an assembly. It was also observed that the presence of identical assemblies upstream and downstream of the single test assembly (multiple assembly case), resulted in drag force increases per sphere from 14% for low concentration to 25% for high concentration. an equation was developed to predict a drag correction factor for Stokes' equation for the multiple assembly configuration based on particle concentration.
SIMPLIFIED PREDICTIVE EQUATIONS FOR VARIABILITY of THERMAL PROCESS LETHALITY
Authors: HAYAKAWA KAN‐ICHI , WANG JIANJUN , DE MASSAGUER PILAR R.
Published: February 2007

A distribution free, analytical formula was derived for estimating variation in heating phase lethality as a function of variations in all independent parameters. Additionally, a regression formula was developed for estimating the coefficient of variation of thermal process lethalities for a fixed z value of 10C as a function of statistically significant parameters. Although process lethalities included both heating and cooling phases of processes, no cooling phase parameter was among the statistically significant parameters. Sample applications of both formulae were presented together with the results of a sensitivity analysis performed using the regression formula.
CALCULATION of INITIAL FREEZING POINT, EFFECTIVE MOLECULAR WEIGHT and UNFREEZABLE WATER of FOOD MATERIALS FROM COMPOSITION and THERMAL CONDUCTIVITY DATA1
Authors: MURAKAMI EDGAR G. , OKOS MARTIN R.
Published: February 2007

A procedure was developed for simultaneous determination of the effective molecular weight, unfreezable water, and initial freezing point of foods based on composition and thermal conductivity data. Freezing properties were determined by trial and error and optimized by minimizing the difference between calculated and reported values of thermal conductivity. the procedure involved determination of the ice fraction at several temperature levels. Corresponding thermal conductivity values at each temperature level were then calculated. Results showed that calculated values of effective molecular weight, unfreezable water, and initial freezing point for various types of meat and fish are comparable to those published. the parallel‐perpendicular model was found an excellent predictor of thermal conductivity of frozen meat and fish with muscle fibers oriented toward the direction of the heat flow.
ANALYSIS of EXPANDED‐FOOD TEXTURE BY IMAGE PROCESSING PART II: MECHANICAL PROPERTIES
Authors: GAO X. , TAN J.
Published: February 2007

Image texture and color features were used to represent the mechanical properties of expanded food products. Texture‐related mechanical properties were measured through Instron shear and compression tests. the image features extracted were found highly correlated with the mechanical properties. the analysis showed useful relationships between geometric properties and mechanical behavior. Image processing proved to be an effective technique for textural analysis of expanded food products.
THE EFFECT OF EDIBLE FILM ON OIL UPTAKE AND MOISTURE RETENTION OF A DEEP‐FAT FRIED POULTRY PRODUCT
Authors: BALASUBRAMANIAM V.M. , CHINNAN M.S. , MALLIKARJUNAN P. , PHILLIPS R.D.
Published: February 2007

The recent trend in reducing the fat content in fried foods is leading to the development of low‐fat products using batter and breading formulations from protein and other hydrocolloids. The functionality of many of these edible ingredients on moisture retention and fat barrier properties during deep‐fat frying is not clearly understood. The objective of this study is to evaluate the effectiveness of hydroxypropyl methylcellulose edible film coating on chicken balls for moisture retention and fat reduction during deep‐fat frying. Two sizes (35 and 47 mm) of uncoated and coated chicken balls were fried in peanut oil at 175C for five different frying periods ranging from 30 to 180s for small and 30 to 300s for large balls. The moisture and fat content from the surface layer and core were determined. In comparison to the control, moisture retention up to 16.4% and fat reduction up to 33.7% were observed.
PREDICTING INTERNAL TEMPERATURE RESPONSE TO CONDUCTION‐HEATING OF ODD‐SHAPED SOLIDS
Authors: KIM K.H. , TEIXEIRA A.A.
Published: February 2007

Heat penetration experiments were carried out in a hot water bath with small blocks of a solid polycarbonate material cut into various shapes (cylinder, cube and oval) to obtain heat penetration factors for each shape. These factors, along with characteristic dimensions from the odd shapes were then used in the finite cylinder heat transfer model to predict accurately the temperature at the center of each block in response to measured dynamic bath temperatures. Results showed sufficiently good agreement between predicted and measured center temperature profiles to justify use of the finite cylinder model for rapid evaluation of process deviations in thermal processing of foods in odd‐shaped containers.
VELOCITY PROFILES OF FLUID/PARTICULATE MIXTURES IN PIPE FLOW USING MRI
Authors: McCARTHY KATHRYN L. , KERR WILLIAM L. , KAUTEN ROBERT J. , WALTON JEFFREY H.
Published: February 2007

Magnetic resonance imaging (MRI) techniques have been utilized to experimentally measure velocity profiles and apparent Theological properties of fluid/paniculate mixtures as functions of flow rate, particle loading, and particle size. The experimental velocity profiles were described by apower law model for these systems. A 3% aqueous sodium alginic acid solution was used to form two particle sizes of 2.5 mm and 5.0mm in diameter. The spheres were suspended in a 0.5% carboxymethyl cellulose solution at loadings ofO, 10, 20, and 30% by weight. The average fluid velocity ranged from 2–35 cm/s. The flow behavior index decreased as flow rate, particle loading or particles size increase. Cumulative residence time curves were evaluated based on this modeling procedure. Results of this research have direct application to aseptic processing of fluid/particulate mixtures.
MOISTURE SORPTION ISOTHERMS FOR KARINGDA (CITRULLUS LANATUS (THUMB) MANSF) SEED, KERNEL AND HULL
Authors: SUTHAR S.H. , DAS S.K.
Published: February 2007

Adsorption‐desorption behaviors of karingda (Citrullus lanatus (Thumb) Mansf) seed, kernel and hull for nine equilibrium relative humidities (ERH) ranging between 11 and 96% at temperatures of 10, 20, 30, 40 and 50C were studied following a static equilibriation technique using saturated solutions of various salts. Under both the adsorption and desorption processes, the equilibrium moisture contents (EMC) of the hull were found to be highest followed by those of the seed and the kernel at all the corresponding temperatures and ERH values. Analysis of these data using four sorption models (modified Henderson, modified Halsey, modified Chung‐Pfost and Guggenheim‐Anderson‐de Boer) and taking the temperature dependence of the respective coefficient into consideration, it revealed that both the Chung‐Pfost and the GAB models were acceptable in describing EMC‐ERH relationships for karingda seed, kernel and hull over the entire range of temperatures. The excess heat of sorption of all the samples, estimated from the Clausius‐Clapeyron equation, decreased exponentially with the increase in moisture content of the same.
TEXTURE DEGRADATION KINETICS OF GELS MADE FROM PACIFIC WHITING SURIMI
Authors: YONGSAWATDIGUL JIRAWAT , PARK JAE W. , KOLBE EDWARD
Published: February 2007

Degradation kinetics of whiting surimi gel texture were examined over a temperature/time range (40–85C, 0.5–35 min). Changes in textural properties of whiting surimi gel were mainly affected by proteolytic activity of endogenous proteinase. A decrease of failure shear stress and shear strain followed first order kinetics. The kinetic parameters developed using either isothermal or nonisothermal principles were similar. Degradation rate of gel texture increased with temperature, reaching a maximum at 55C. It then decreased to a minimum at 70C. Ea values for the activation and inactivation temperature range were 138.6–162.6 and 13.5–35.0 kJ/mol, respectively.
CLASSIFICATION OF ON‐LINE POULTRY CARCASSES WITH BACKPROPAGATION NEURAL NETWORKS1
Authors: CHEN Y.R. , PARK B. , HUFFMAN R.W. , NGUYEN M.
Published: February 2007

A transportable system equipped with an overhead shackle conveying line and a visible/near‐infrared (Vis/NIR) spectrophotometer system was assembled and used at a poultry slaughter plant. The reflectance spectra of each poultry carcass hung on the moving shackle was measured with a stationary fiber optic probe, which was set 2 to 5 cm away from the carcass, depending on the size. Reflectance spectra of wholesome and unwholesome poultry carcasses on the moving shackle, set at 60 or 90 birds/min, were measured, either under room light or in a dark environment. The scanning time for each carcass was 0.32 s. Most of the unwholesome poultry carcasses for this study were septicemic and air‐sacculitic. The average accuracy in classifying wholesome and unwholesome carcasses was above 94%. All the misclassified carcasses were air‐sacculitic. With a shackle speed of 90 birds/min, the highest average accuracy was obtained when the reflectance was measured in the dark (97.5%). The results showed that the accuracy of classification could be improved with the maintenance of a consistent lighting environment. All results indicated the Vis/NIR spectrophotometer system would be a highly accurate, robust tool for on‐line, real‐time classification of wholesome and unwholesome carcasses.
ELECTRICAL CONDUCTIVITIES OF HYDROCOLLOID SOLUTIONS
Authors: MARCOTTE M. , PIETTE J.P.G. , RAMASWAMY H.S.
Published: February 2007

Ohmic heating was applied to solutions of 5 hydrocolloids (carrageenan, 1–3% w/w; xanthan, 1–3% w/w; pectin, 1–5% w/w; gelatin, 2–4% w/w and starch, 4–6% w/w) in a static cell to study the effect of concentration and temperature on electrical conductivities. For each experiment, the sample was poured into the cell and heated at a constant voltage gradient of 7.24 V/cm. Voltage, current, time and temperature were logged at time intervals and used to calculate electrical conductivities as a function of temperature. Of the thickening agents examined, carrageenan gave the highest value for electrical conductivity (0.2 S/m at 25C and 1% and 1.4 S/m at 100C and 3%) followed by xanthan (0.14 S/m at 25C and 1% to 1.1 S/m at 100C and 3%). Pectin and gelatin samples were found to exhibit lower, but similar electrical conductivities (0.06 S/m at 25C at the lowest concentration to 0.37 S/m at 100C at the highest concentration). Starch samples had the lowest electrical conductivity varying from 0.05 S/m at 25C and 4% to 0.21 S/m at 100C and 6%. Regression equations were established for each type of hydrocolloid solutions revealing a strong interaction between the concentration and the temperature and the electrical conductivity values. Major differences were observed between hydrocolloid types on electrical conductivities that were mainly attributed to their ash content.
HIGH TEMPERATURE RHEOLOGY OF TOMATO PUREE AND STARCH DISPERSION WITH A DIRECT‐DRIVE VISCOMETER
Authors: RAO M.A. , COOLEY H.J. , LIAO H‐J.
Published: February 2007

A direct‐drive concentric cylinder viscometer in a pressure chamber was used to study the flow behavior of a 11 Brix tomato puree at several temperatures in the range: 76 to 120C. The activation energy of flow of the tomato puree, based on apparent viscosity at 50 s−1, was: 9.4 kJ mol−1. The apparent viscosity (η) versus temperature profiles of a 4.0% waxy rice (WR) starch dispersion were determined during continuous heating from 30 to 110C at six shear rates in the shear range: 114 to 644 s−1; beginning at about 95C, significant increase in ηa was observed at 114 and 160 s−1. The said profiles collapsed to a single curve when ηa values were converted to reduced viscosity, values of η of the starch dispersion were lower than those of η* at about the same shear rates, γ=5.7 s−1 and ω=6.3 rad s−1.
FLOW BEHAVIOR AND RHEOLOGICAL MODELS OF RICE FLOUR PASTES
Authors: WANG HAI‐HONG , SUN DA‐WEN , ZENG QINGXIAO , LU YINQUAN
Published: February 2007

Rheological properties of a popular Chinese rice flour pastes were determined with a rotational viscometer at different levels of concentration and temperature. The rice flour had intermediate amylose content, medium gel consistency and high birefringence‐endpoint temperature (BEPT). Cooked pastes exhibited shear‐thinning behavior without yield stress at the concentration levels of 2∼6% and temperatures of 25∼80C and their flow properties were represented by a power law model. The effects of concentration and temperature on consistency index, flow behavior index and apparent viscosity were investigated.
MICROBIAL, CHEMICAL AND PHYSICAL CHANGES IN CHILL WATER TREATED WITH ELECTROCHEMICAL METHOD
Authors: MA LI , YANG ZHONGPING , LI YANBIN , GRIFFIS CARL
Published: February 2007

A three‐zone (anode, neutral, and cathode) electrochemical treatment chamber was designed and built to evaluate the inactivation of Salmonella typhimurium in poultry chill water. The chill water in the three‐zone chamber containing ∼106 CFU/mL S. typhimurium and 0.5% or 1.0% NaCl was treated at 15 or 25 mA/cm2, and a temperature of 5–10C for up to 10 min. The Salmonella were inactivated within 0.5 to 4 min in the anode zone depending on the salt concentration and current density, slower inactivation rate in the cathode zone, and almost no inactivation in the neutral zone. The pH decreased to ∼ 2 in anode zone, but increased to ∼ 10 in the cathode zone. Temperature increased by 2–6.5C in the three zones depending on current density and salt concentration. The conductivity increased in the anode and cathode zones but little change in the neutral zone. The generated chlorine was proportional to the current density and the treatment time.
VISCOELASTIC FLOW MODELING IN THE EXTRUSION OF A DOUGH‐LIKE FLUID
Authors: DHANASEKHARAN MUTHUKUMAR , KOKINI JOZEF L.
Published: February 2007

This work attempts to investigate the effect of viscoelasticity and three‐dimensional geometry in screw channels. The Phan‐Thien Tanner (PTT) constitutive equation with simplified model parameters was solved in conjunction with the flow equations. Polyflow, a commercially available finite element code was used to solve the resulting nonlinear partial differential equations. The PTT model predicted one log scale lower pressure buildup compared to the equivalent Newtonian results. However, the velocity profile did not show significant changes for the chosen PTT model parameters. Past Researchers neglected viscoelastic effects and also the three dimensional nature of the flow in extruder channels. The results of this paper provide a starting point for further simulations using more realistic model parameters, which may enable the food engineer to more accurately scale‐up and design extrusion processes.
RHEOLOGICAL PROPERTIES OF NONCOHESIVE APPLE DISPERSION WITH HELICAL AND VANE IMPELLERS: EFFECT OF CONCENTRATION AND PARTICLE SIZE
Authors: CANTÚ‐LOZANO DENIS , RAO M.A. , GASPARETTO C.A.
Published: February 2007

The proportionality constant, ks, between shear rate, γ, and agitation velocity, N, for a helical ribbon‐screw (HRS) agitator was 17.8. Using the HRS agitator, values of consistency index K and the flow behavior index n of 14 apple pulp suspensions at seven different solids concentrations and two average particle diameters 0.71 mm and 1.21 mm were determined; in addition, values of the Casson viscosity ηc and yield stress σOC were also calculated. The magnitudes of K increased and of n decreased with increase in pulp concentration. Experimental values of the vane yield stress, σOν, measured with a six‐blade vane increased with increase in pulp content. The values of σOC obtained using the Casson model were close to the experimental values σOν. The effect of particle size on the relative viscosity, ηr, was correlated with Peclet number.
PECAN TEXTURE AS AFFECTED BY MOISTURE CONTENT BEFORE FREEZING AND THAWING RATE
Authors: SURJADINATA B.B. , BRUSEWITZ G.H. , BELLMER D.D.
Published: February 2007

The texture of pecans was determined as affected by initial moisture content before freezing (3 vs 5%), thawing rate (IX, 1.2X, 2.7X, 5.6X), and multiple freeze‐thaw cycles (0, 1X, 3X, 6X, 9X, 12X). Texture was determined by instrumental Texture Profile Analysis (TPA) and sensory evaluation. Initial moisture content before freezing had a significant effect on all of the sensory evaluation parameters (hardness, fracturability, cohesiveness, and denseness) and most of the instrumental TPA texture parameters (hardness, fracturability, springiness, resilience, and chewiness). Thawing rate only affected TPA hardness and resilience. TPA fracturability correlated best with sensory fracturability. The sensory panel could not detect any differences between the different thawing rates. The slowest thawing rate affected more parameters than the medium and faster rates. More freeze/thaw cycles significantly decreased most TPA texture values, especially for pecans at higher moisture content.
THERMAL PROPERTIES OF RADISH AND ALFALFA SEEDS
Authors: YANG JUN , ZHAO YANYUN
Published: February 2007

Thermal conductivity, specific heat, and density were measured in a temperature range of 30C to 80C, and moisture content of 4.6% to 6.5% for radish seeds, 5.0% to 7.3% for alfalfa seeds typically encountered in the radio frequency dielectric heating for seeds. Thermal conductivity and specific heat were determined using a linear heat source probe and a modified calorimeter method, respectively. Thermal conductivity of radish and alfalfa seeds ranged from 0.050 to 0.091 W/mC (SD: 0.011) and 0.075 to 0.120 W/mC (SD: 0.012), respectively. Specific heat was in the range of 0.290 to 0.479 kJ/kgC (SD: 0.051) for radish seeds and 0.333 to 0.593 kJ/kgC (SD: 0.076) for alfalfa seeds. Density of radish and alfalfa seeds ranged from 684 to 675 kg/m3 (SD: 5.592) and 819 to 804 kg/m3 (SD: 8.921), respectively. Thermal diffusivity of the seeds was also determined, and the values varied from 25.13 × 10−8 to 34.47 × 10−8 m2/s for radish seeds and 27.14 × 10−8 to 29.73 × 10−8 m2/s for alfalfa seeds. Regression models were fitted to the experimental data for each thermal property, and showed second order polynomial relationships with temperature and moisture content.
USE OF ABLATION TO DETERMINE THE CONVECTIVE HEAT TRANSFER COEFFICIENT IN TWO‐PHASE FLOW
Authors: TESSNEER W. ADAM , FARKAS BRIAN E. , SANDEEP K.P.
Published: February 2007

The fluid to particle convective heat transfer coefficient (hfp) is an essential design parameter in the development of an aseptic processing system. The convective heat transfer coefficient was determined using a new method based on ablation heat transfer. The amount of solid lost (ablated) was shown to be directly proportional to the energy flux across the fluid‐solid interface with the constant of proportionality being hfp. Change in mass of an ice sphere was used as an ablation probe to study hfp in straight, round conduit. Values of hfp ranged from 1,369 to 2,749 W/m2K over a Reynolds number range of 2,766 to 17,081.
A PREDICTIVE MODEL FOR THERMAL CONDUCTIVITY OF AN INTERMEDIATE MOISTURE GRANULAR FOOD
Authors: SABLIOV CRISTINA M. , HELDMAN DENNIS R.
Published: February 2007

A mathematical model for prediction of thermal conductivity of granular foods was developed to consider the influence of moisture content and bulk density. The range of moisture contents considered was from approximately 20% (db) to 150% (db). The model considers the influence of thermal conductivity and volume fraction of product solids and water as a first step in predicting thermal conductivity of product particles. The second step in the predictive model considers thermal conductivity and volume fraction of the product particles and air when predicting effective thermal conductivity of the food system. The model was evaluated by comparison of model outputs with experimental measurements for casein and corn meal starch particles. Experimental measurements of thermal conductivity were obtained using a thermal conductivity probe. The model provided excellent prediction of effective thermal conductivity over the entire moisture content range. Statistical agreement was described by standard errors of 0.0143 W/mK (7.2%) for starch at 25C, 0.01835 W/mK (12.1%) for casein at 25C, and 0.02584 W/mK (16.4%) for casein at 40C, with most of the variability associated with experimental measurements.
MICROFILTRATION OF RED BERRY JUICE WITH THREAD FILTERS: EFFECTS OF TEMPERATURE, FLOW AND FILTER PORE SIZE
Authors: BAGGER‐JØRGENSEN RICO , CASANI SANDRA , MEYER ANNE S.
Published: February 2007

A series of experiments was conducted to demonstrate the applicability of a new Filtomat® thread filtration principle for microfiltration of semiprocessed blackcurrant juice and cherry juice. The effect of juice temperature (3–20C), flow (20–80 L/h), and filter pore size (3–10 μm) on the transmembrane pressure, juice turbidity, protein, sugar, and total phenols levels was evaluated in a lab scale microfiltration unit employing statistically designed factorial experiments. Thread microfiltration reduced significantly the turbidity of both juices. For blackcurrant juice, in all experiments, the turbidity was immediately reduced to the level required for finished juice without compromising either the protein, the sugar or the phenols content. High flow rates increased the turbidity in blackcurrant juice, but did not affect cherry juice quality. Filtomat® thread microfiltration therefore appears suitable as a novel technology for berry juice processing, especially for blackcurrant juice filtration.
MODELING AND OPTIMIZATION OF CONSTANT RETORT TEMPERATURE (CRT) THERMAL PROCESSING USING COUPLED NEURAL NETWORKS AND GENETIC ALGORITHMS
Authors: CHEN C.R. , RAMASWAMY H.S.
Published: February 2007

Coupled artificial neural network (ANN) models and genetic algorithms (GA) were applied for developing prediction models and for optimization of constant temperature retort (CRT) thermal processing of conduction heating foods. ANN prediction models were developed for process time (Pt), average quality retention (Qv), surface cook value (Fs), equivalent energy consumption (En), final temperature difference (Tg) at can center, and lethality ratio (p, heating/total lethality). The processing conditions as inputs for ANN models were as follows: retort temperature (RT = 110–140C), thermal diffusivity (α= 1.1–2.14*10−7m2/s), volume of can (V = 1.64–6.55*10−4m3), ratio of height to diameter of can (Rdh= 0.2–1.8), total desired lethality value (F0= 5–10 min) at can center and quality kinetic destruction parameters: decimal destruction time (Dq– 150–300 min) and their temperature dependence (zq= 15–40C). The data for training and testing ANN models were obtained from a finite difference computer simulation program. A second order central composite design was used for constructing the experimental data for training ANN models, while an orthogonal experimental design with 6 factors and 3 levels was used for the generalization of trained ANN models. ANN model linked Genetic Algorithms (GA) were employed for searching for the optimal quality retention and corresponding retort temperature, and for investigating the effects of main processing factors. ANN‐based prediction models successfully described the various outputs of CRT thermal processing (correlation coefficients: R2 > 0.98; relative errors: Er ≤ 3%). The coupled ANN‐GA models, verified under several typical processing conditions, could be effectively used for optimization of CRT thermal processing. The main processing conditions and their interactions in the order of their importance with respect to the optimal quality retention and corresponding retort temperature were: V >zq >Rdh >; and zq >Fd > Rdh >V, respectively.
THE CONTINUOUS WOK — A NEW UNIT OPERATION IN INDUSTRIAL FOOD PROCESSES
Authors: ADLER‐NISSEN JENS
Published: February 2007

The preparation of fine cut vegetables and meat by stir‐frying is characterized by a short cooking time and high rates of heat and mass transfer, which makes scale‐up difficult. A new principle for carrying out an industrial, continuous stir‐frying process is studied at pilot plant scale. The ingredients are transported in a horizontal, open frying tube by a conveyor helix while being tossed by scrapers and stirring rods mounted on the helix. During the frying process the average product temperature stabilizes around 80C, despite the intense heating, and this may explain why the texture of stir‐fried vegetables is firmer than the texture of vegetables cooked in water. However, the heat inactivation of a model microorganism applied as a surface contaminant showed that the effective surface temperature was above 90C which ensures a safe process. Vigorous evaporation from the free surfaces of the turning pieces may cause this temperature gradient to be established by an evaporation cooling effect.
EXPERIMENTAL EVALUATION OF THE PERFORMANCE OF VACUUM COOLING METHOD FOR LARGE COOKED MEAT JOINTS
Authors: WANG LIJUN , SUN DA‐WEN
Published: February 2007

The cooling rate, weight loss and temperature distribution of large cooked meat joints during vacuum cooling are experimentally analyzed. For cooling cooked meat joints with a weight of more than 5 kg from an initial temperature of around 74C to a final temperature of 10C, the experimental results showed that the total cooling time for vacuum cooling was less than 2 h, compared with over 5 h, 7 h and 9 h for water immersion, air blast and slow air cooling, respectively. During vacuum cooling, meat weights had no significant effect on the cooling rate and the maximum temperature point was not always located in the geometrical center of meat body. Vacuum cooling meat resulted in a higher weight loss, which was as high as about 10–13 % of the weight before cooling, in comparison with 6–7% for slow air and air blast cooling. However, the moisture loss of cooked meats during vacuum cooling can be reduced by manipulating the brine injection levels.
A MIXER VISCOMETRY APPROACH FOR BLENDING DEVICES
Authors: GLENN T.A. , DAUBERT C.R.
Published: February 2007

The Matching Stress Method is a mixer viscometry technique used to estimate mixer constants and viscosity using systems of complex geometry. Three Newtonian standards and three hydroxy‐propyl‐methyl‐cellulose (HPMC) solutions were used as model systems. to determine the mixer constants, a counter‐rotating, twin‐rotor blender was modified with a torque transducer and speed sensor installed between a drive shaft and a 0.75 hp (559.3 W) electrical motor. Mixer constants were determined using a concentric cylinder approximation of shear stress in an effort to match this approximation with shear stress measurements determined from a bench top rheometer. Mixer constants for the model systems ranged between 2.01 and 2.87 rad−1 with an average value of 2.57 rad−1 for all fluids. the results demonstrate a successful technique for providing accurate viscometric data during mixing processes. Such efforts could be followed to implement real time, quality control strategies and power estimation in scale‐up procedures.
PRESSURE DROP ESTIMATION IN TUBE FLOW of NON‐NEWTONIAN FLUID FOODS BY NEURAL NETWORKS
Authors: SINGH PAWAN P. , JINDAL VINOD K.
Published: February 2007

A tube flow viscometer complete with data acquisition system was designed and developed for continuous measurement of pressure drop and flow velocity. Experiments were carried out with tomato ketchup, oyster sauce, mayonnaise, and 1% and 1.5% CMC solutions in the laminar flow region using stainless steel tubes of four diameters (0.00751–0.01636 m). the flow parameters determined with the tube viscometer after slip correction and a rotational viscometer were correlated for estimating the pressure drop indirectly. Finally, it was shown that neural networks could accurately predict the pressure drop in tube flow without making any correction for wall‐slip from the input data on tube diameter, fluid density, mass flow rate, and power‐law parameters determined with a rotational viscometer. Among three neural network architectures tested, the generalized regression neural networks were most easy to train and they predicted the pressure drop gradient in tube flow with greatest accuracy (4.7% average absolute error).
HIGH PRESSURE DESTRUCTION KINETICS of INDIGENOUS MICROFLORA and ESCHERICHIA COLI IN RAW MILK AT TWO TEMPERATURES
Authors: PANDEY PRAMOD K. , RAMASWAMY HOSAHALLI S. , IDZIAK EDMUND
Published: February 2007

Raw milk with a high count of indigenous microflora, with and without inoculated Escherichia coliK‐12 (ATCC‐29055), was subjected to high pressure treatment (250–400 MPa) for various holding times (0–80 min) at two temperatures (3 and 21C). From the microbial survivor data, an instantaneous pressure kill value (IPK) which represented the effect of a pressure pulse, and kinetic parameters (rate constant, D‐value, z‐value and activation volume) were evaluated based on pressure hold‐time first order kinetics. Both IPK and D values were dependent on pressure level and temperature. Higher pressures, longer holding times and lower temperatures resulted in larger destruction of microorganisms, and E. coli was more pressure sensitive than indigenous microflora. Pressure dependency of kinetic parameters was well described by both pressure death time and Eyring‐Magee models. At 3 and 21C, the zp values were 227 and 240 MPa and λV# values were −2.32 and −2.34 (x 10−5 m3 mole−1), respectively, for indigenous microflora, and 179 and 205 MPa (zp) and −2.95 and −2.75 (x 10−5 m3 mole−1) (λV#), respectively, for E. coli.
KINETICS of QUALITY CHANGE DURING COOKING and FRYING of POTATOES: PART I. TEXTURE
Authors: NOURIAN F. , RAMASWAMY H.S.
Published: February 2007

Kinetics of texture change during cooking and frying of potatoes were evaluated in this study. Potatoes were cut into cylinders (diameter × height: 20 mm × 20 mm for cooking, and 10 mm × 20 mm for frying) and cooked in a temperature controlled water bath at 80–100C or fried in a commercial fryer at 160–190C for selected times. the cooked samples were water cooled while the fried samples were air cooled immediately after the treatment. Test samples were then subjected to a single cycle compression test in a computer interfaced Universal Testing Machine and three textural properties (hardness, stiffness and firmness) were derived from the resulting force‐deformation curves. Texture parameters of cooked potatoes decreased with progress of cooking time and the rate of texture changes associated with each temperature was found to be consistent with two pseudo first‐order kinetic mechanisms, one more rapid than the other. Textural values of fried potatoes were found to increase with frying time and also followed a first order kinetic model. Temperature sensitivity of rate constants was adequately described by Arrhenius and z‐value models.
DYNAMIC ANALYSIS of the COOLING PROCESS IN PLATE HEAT EXCHANGERS
Authors: BERTO MARIA ISABEL , JUNIOR VIVALDO SILVEIRA
Published: February 2007

This paper describes a dynamic simulation of a mathematical model that describes the cooling process of natural orange juice in plate heat exchangers. the goal was to obtain an evaluation of the process reaction curves, represented by the behavior of the outlet orange juice's temperature after simultaneous disturbances to the following process variables: product and refrigerant fluid temperatures and mass flow rates. the simulator was encoded using the Mat‐Lab program, whose effectiveness had been previously validated (predicted values were within 2% of the published values). Assays were simulated based on the factorial design technique. the importance of variable interaction was evaluated and it was shown that each combination of disturbances to the process gave way to different effects on outlet temperature stabilization values and on the behavior of process reaction curves. the monitoring of the process variable transient behavior has been found to aid in tuning controllers throughout this process, which requires, according to the results, nonconventional coutrollers for truly efficient automation.
EFFECT OF MECHANICAL TREATMENT ON THE HARDNESS OF MARGARINE AND BUTTER
Authors: MAN J.M.DE
Published: February 2007

The work‐softening of margarine and butter resulting from passage through perforated plates was determined. Various plates were used differing in size and number of perforations, but identical in the total area of perforations. Greater work‐softening was obtained with plates having many small perforations, but the back‐pressure in the equipment was higher. Passing the product through two or three plates slightly increased work softening. Additional mechanical action was provided by a propeller rotating immediately behind the perforated plates. Only small additional work‐softening was obtained by this action and little remained after 8 days storage. Increasing the speed of the propeller up to 100 r.p.m. increased work softening. Increasing it to 300 r.p.m. did not further increase work softening. It appears that excessive mechanical action has little permanent softening effect on plastic fats.
BEHAVIOR OF DIFFERENT FOODS IN THE STANDARD SHEAR COMPRESSION CELL OF THE SHEAR PRESS AND THE EFFECT OF SAMPLE WEIGHT ON PEAK AREA AND MAXIMUM FORCE
Authors: SZCZESNIAK ALINA S. , HUMBAUGH PHILIP R. , BLOCK HARRY W.
Published: February 2007

Abstract Twenty‐four foods (encompassing fruits, vegetables, meat, bread, cheese and rice) were tested in the Allo Kramer Shear Press at various weight levels ranging from those needed to cover the bottom of the cell to those required for a complete fill. The relationship between maximum force values and sample weight was found to be different for different foods. Products could be grouped into three general categories: those exhibiting a constant force to weight ratio (e.g. white bread, sponge cake), those exhibiting a continuously decreasing force to weight ratio (e.g. raw apples, cooked white beans), and those exhibiting a constant force, independent of sample weight, beyond a certain cell fill level (e.g. canned beets, canned and frozen peas). Fitting the observed behavior into mathematical models allows to infer that extrusion, in addition to the previously recognized shear and compression, plays an important role in the behavior of foods in the standard cell of the Shear Press, and that most foods are subject to various combinations of these forces. The contribution of extrusion was confirmed by actual extrusion tests. Peak areas showed an exponential relationship to sample weight following the equation A = l0aWb. Some evidence was obtained that exponents a and b are related to the amount and the general type of resistance offered by the food.
COLLECTION AND CLASSIFICATION OF WORDS FOR DESCRIPTION OF FOOD TEXTURE
Authors: YOSHIKAWA S. , NISHIMARU S. , TASHIRO T. , YOSHIDA M.
Published: February 2007

A correlation matrix was computed from the rating score matrix of texture profiles of 79 foods. Multivariate analysis yielded eight orthogonal factors. The most important dimensions were: hard ↔ soft, cold ↔ warm, oily ↔ juicy, elastic ↔ flaky, heavy, viscous, smooth.