• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.66-71
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• 2001

Kinetic parameters for the texture degradation of three varieties of sweet potato during heating were determined using two alternative methods, the biphasic model and the fractional conversion method. The texture degradation of sweet potatoes during heating could be expressed by two simultaneous first order reactions using the biphasic method, whose activation energies were ranged $71.0{\sim}75.1\;kJ/mol\;and\;48.4{\sim}59.6\;kJ/mol$ for the initial fast texture degradation reaction and the slow texture degradation reaction at a prolonged heating period, respectively. However, the whole texture degradation phenomena of sweet potatoes during heating could also be explained by a single first order reaction using the fractional conversion method. The activation energies were $67.5{\sim}75.3\;kJ/mol$, which were comparable with those of the first phase reaction for the texture degradation determined by the biphasic model. A kinetic compensation effect shown between the kinetic parameters determined by both methods indicates that both methods can be conveniently used to determine kinetic parameters for the texture degradation of sweet potatoes by heating.

• Food Engineering Progress
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• v.21 no.4
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• pp.303-311
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• 2017

To automate cooking processes, quantitative descriptions are needed on how quality parameters, such as texture change during heating. Understanding mechanical property changes in foods during thermal treatment due to changes in chemical composition or physical structure is important in the context of engineering models and in precise control of quality in general. Texture degradation of food materials has been studied widely and softening kinetic parameters have been reported in many studies. For a better understanding of kinetic parameters, applied kinetic models were investigated, then rate constants at $100^{\circ}C$ and activation energy from previous kinetic studies were compared. The food materials are hardly classified into similar softening kinetics. The range of parameters is wide regardless of food types due to the complexity of food material, different testing methods, sample size, and geometry. Kinetic parameters are essential for optimal process design. For broad and reliable applications, kinetic parameters should be generated by a more consistent manner so that those of foods could be compared or grouped.

• Journal of Korea Soil Environment Society
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• v.5 no.2
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• pp.3-12
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• 2000

This study was carried out to evaluate the effect of aeration on removal of phenolic compounds in soils. Phenol, 2,4-dichlorophenol, and pentachlorophenol as phenolic compounds were chosen in this study. Texture of soil used was sandy loam. Temperature and moisture content of the soils in lab-scale reactors were maintained at $25^{\circ}C$ and at 15%, respectively. Phenolic compounds vaporized from reactors were trapped by methylene chloride solution. Phenolic compounds were applied to the soils as individual compound Aeration improved the phenol degradation rate in soil, while it did not in case of 2,4-dichlorophenol and pentachlorophenol. The amount of phenol vaporized by aeration was only 0.3of of that of initial phenol compound added to the soil. First order kinetics described the degradation rates of phenolic compounds better than zero order kinetics.