摘要:

ABSTRACTTemperature fluctuations of frozen foods are of influence on frozen food quality. Prediction of quality changes under temperature fluctuations is therefore important in assuring high product quality and, by optimizing storage temperature, in conserving energy. This study is focused on applying kinetic models in analyzing Time‐Temperature‐Tolerance (TTT) data for frozen food storage and investigating the potential for use of kinetic parameters to describe quality degradation in frozen foods.Based on theoretical considerations, quality life and activation energy are related by the equation:lntQ= lnB+Ea/R· 1/Twhere B is a function of the pre‐exponential of Arrhenius equation, initial and end point quality magnitude.Reasons for some TTT data to deviate from this relationship are:A.Different standards for measuring quality lives of different storage temperatures or experiments.B.Negative effect of temperature.C.Variations in initial or final quality magnitudes for a given experiment.D.Variations in packaging material and other factors influencing the quality magnitude or mode.ITT experiments are suitable approaches for obtaining activation energy constants, although they are not applicable for determination of reaction order and rate constant. When dealing with overall quality life of several contributing factors, quality life for each component is needed to get a better description. Quality changes in terms of fraction of initial quality magnitude retained can be described by quality life, activation energy, temperature history and the constant, α=

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1982.tb00291.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTMathematical models, which are amalgams of empirical equations and reaction kinetics, were used to predict the destruction of available lysine in proteins. R2‐values for plots of predicted versus observed values ranged from 0.8 to 0.9. Changes in water activity, sugar, salt, oil, pH, time and temperature are considered by the model. The model can adjust for different sugars by employing an algorithm based upon the mutarotation constant for a specific sugar. A plot of sugar mutarotation constant against the appropriate loss rate coefficient demonstrated the relation between these two measures (R2= 0.8). Nomograms for predicting the loss rate coefficient and the activation energy, which can be used in an industrial application, are presente

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1982.tb00292.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTA family of models has been developed which has the ability to simulate transient shear stress growth in foods. The models can be written as follows:Three relaxation terms (seven parameters) are necessary to stimulate transient shear stress growth for stick butter, tub margarine and peanut butter at shear rates of 10 s−1and 100 s−1.At small times the model tends to:which simulates the stress growth part of the curve. At long times the models tend to the power‐law. The series of relaxation terms allows for the introduction of several time scales in the relaxation behavior of each

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1982.tb00293.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1982.tb00294.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

ISSN:0145-8876    

DOI:10.1111/j.1745-4530.1982.tb00295.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY