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THE EFFECT of INTERNAL THERMAL GRADIENTS ON the RELIABILITY of SURFACE MOUNTED FULL‐HISTORY TIME‐TEMPERATURE INDICATORS
Author(s) -
MALCATA F. XAVIER
Publication year - 1990
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/j.1745-4549.1990.tb00148.x
Subject(s) - thermal diffusivity , dimensionless quantity , reliability (semiconductor) , scaling , function (biology) , univariate , thermodynamics , thermal , expression (computer science) , biological system , quality (philosophy) , mechanics , econometrics , environmental science , statistics , mathematics , chemistry , computer science , physics , power (physics) , geometry , multivariate statistics , quantum mechanics , evolutionary biology , biology , programming language
A simple analytical expression aimed at assessing the theoretical reliability of a full‐history time‐temperature indicator placed on the surface of a food item as a predictor of the remaining shelf‐life in the presence of heat transfer limitations within the food is obtained. Such expression, which depends on three dimensionless parameters only, can be written as a univariate function of a single parameter containing the thermal properties of the food via a suitable algebraic scaling. the derivation of the relevant formulae is based on the integration of a generic quality function across the slab‐shaped food item under the assumption that the temperature on the surface of the food undergoes a sinusoidal variation with time. the analysis reported is useful because it provides a quick estimate of the effect of the thermal diffusivity of the food on the relative error associated with the use of a TT1 when the activation energies of the food and the indicator are matched (as should happen in the idealistic case) under realistic environmental conditions of storage.