Showing papers in "Journal of Food Engineering in 1991"

TL;DR: In this article, the Clausius-Clapeyron equation was applied to the sorption isotherms at different temperatures to calculate the isosteric heat of water desorption and adsorption.

TL;DR: In this article, the Clausius-Clapeyron equation was used to determine the net isosteric heat of sorption of five dried fruits (sultana raisins, currants, figs, prunes and apricots) in the temperature range 15-60°C.

TL;DR: The ICRS/DS algorithm as discussed by the authors is based on the combination of a robust parameterization of the control function and a computationally efficient nonlinear programing algorithm of unconditional convergence, which is applied to the optimization of the thermal processing of conduction-heated canned foods, attaining for the first time optimum temperature-time profiles for different objective functions.

TL;DR: In this article, a diffusion model was used to study the drying characteristics of sliced tomato specimens and an equation was also developed to estimate the drying time to reach a particular moisture level.

TL;DR: In this article, three regression methods were used to fit the GAB (Guggenheim-Anderson-de Boer) model to the experimental results and the direct nonlinear weighted regression analysis was shown to be the preferred procedure for estimating the six constants of GAB model and predicting the moisture sorption isotherms of the dried products over the temperature range tested.

TL;DR: In this article, a modified Crank approach was used to determine the diffusion coefficient in systems where volume changes occur during dyring of raw and blanched potato at two temperatures: 60 and 80°C.

TL;DR: The model developed by Toupin was used to describe the mass transfer of sucrose and water in potato material and this model was modified to give a closer thermodynamical description of the forces involved in the osmotic process.

TL;DR: In this article, a model for the unsteady state drainage of a standing foam has been proposed, which accounts for the liquid drainage from plateau borders due to gravity as well as the gradient of plateau border suction and the movement of the foam-liquid interface due to the accumulation of drained liquid.

TL;DR: In this article, a mathematical model based on simultaneous gas diffusion and chemical reaction was developed to represent the gas exchange in foods stored in modified atmospheres, and the experimental methods were analyzed based on the model to determine the properties of apples.

TL;DR: A literature review on the mathematical modelling of thermal properties and measuring methods is presented in this article, where the importance of the temperature steps when using stepwise differential scanning calorimetry to measure the specific heat and enthalpies is discussed.

TL;DR: In this article, a refinement of the Guggenheim-Anderson-de Boer (GAB) sorption model was used to analyze the behavior of adsorption isotherms of starches at very high water activity.

TL;DR: In this article, the authors investigated the diffusion coefficient of potato slabs at different initial moisture contents and thicknesses and measured the variation of surface area with time in order to consider the degree of shrinking of the samples during drying.

TL;DR: In this paper, an analytical method for the calculation of freezing and thawing times of foods of high water content has been developed based on an equation relating the temperature at the thermal centre of the food to a dimensionless variable that takes into account the simultaneous influence of time, process parameters and also the thermophysical properties and size of the product.

TL;DR: In this article, the cooking extrusion of wheat, rye, barley and oat flour has been studied and modelled using response surface methodology with changing process variables using two screw configurations.

TL;DR: In this paper, the authors used a coaxial cylindrical viscometer to study the flow properties of tamarind (Tamarindus indica L.) juice concentrate over a concentration range of 7-62 °Brix and a temperature range of 298-343 K.

TL;DR: In this article, the water activity (a w ) was measured on thawed mixed minced meats, minced meat, and white bread dough, and the values of the constants a and n were found to be ln a = − 0·0026T + 3·297 and n = 0·565 for the mixed minced meat and ln n = −0·0071T + 4·50 and n= 0·380 for the dough.

TL;DR: In this paper, the nonlinear dynamic behavior of a double effect tomato paste evaporator system is modeled using Advanced Continuous Simulation Language (ACSL) and the governing equations were solved using ACSL.

TL;DR: In this paper, the authors used a concentric cylinder viscometer to measure the shear rate-shear stress data for tamarind kernel powder (TKP) suspensions.

TL;DR: The proximate composition, density, specific heat and viscosity of various dilutions of cow's milk and soymilk produced from each of two local varieties of soya beans (TGX 330-0102D and Doko) were determined at 25°C and subjected to regression analyses in order to determine the relationships between the percentage of total solids (%TS) and each of these primary physical properties as mentioned in this paper.

TL;DR: A mathematical model based on the binary diffusion equation and the inactivation kinetics can be developed that describes the in activation of α-amylase during drying.

TL;DR: In this paper, the effective thermal diffusivity (αeff) of two granular starches was determined directly and indirectly, using the heated probe method of unsteady-state heat conduction.

TL;DR: In this article, the authors proposed a shorter and less waste water-consuming process for ripe olive processing, which consists of treating the olives with a sodium hydroxide solution followed by a water rinse at 50°C. After 13-24 h the product has developed a sufficiently good colour to be packed.

TL;DR: In this paper, the physical changes occurring during the so-called "boixet" step of the manufacturing process of Xixona turron have been studied and an attempt has been made to explain the role of major turron components in this change by using rheological measurements and particle-size analysis techniques.

TL;DR: In this paper, a device was developed for measurement of thermal conductivity of solid food materials above and below freezing, which is a modification of the Fitch apparatus, where a disc-shaped sample with a constant thickness is placed in the compartment between a copper rod and a copper disc.

TL;DR: In this article, the shape factors of ellipses and ellipsoids were obtained by assuming that the freezing front is similar in shape to the surface, and a curve-fitting expression was proposed that agreed with numerical results to within 6%.

TL;DR: In this paper, a 50·6g spherical steel indentator, with a radius of curvature of 0·94 cm, was dropped on to the fruit from three heights: 4, 6 and 10 cm (0·0199, 0·0299 and 0·0499 J).

TL;DR: In this paper, a short review of models for the calculation of thawing time and simulation of the process is given, with the emphasis on the heat and mass transfer at the surface of the product.

TL;DR: In this article, the residence time distribution (RTD) of an APV-Baker MPF-50 type corotating, twin-screw extruder is measured by a radiotracer technique.

TL;DR: In this article, an externally controlled drying model, involving the heat and mass transfer coefficients as model parameters, was proposed for an industrial belt dryer for moisture removal from raisins, and a nonlinear regression procedure was applied to fit the model to experimental data on material moisture content and temperature.

TL;DR: In this paper, a dimensionless equation has been developed to predict the settling time of a sphere in a Herschel-Bulkley fluid subjected to sinusoidal vibration, which is used to determine the effect of random vibrations as induced in a shipping environment.