Thermal Food Processing

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CONTENTS
Thermal Physical
Properties of Foods
A.E. Delgado, Da-Wen Sun, and A.C. Rubiolo
1.1 Introduction..................................................................................................3
1.2 Definition and Measurement of Thermophysical Properties......................4
1.2.1 Specific Heat Capacity ....................................................................5
1.2.2 Enthalpy...........................................................................................5
1.2.3 Thermal Conductivity......................................................................6
1.2.4 Thermal Diffusivity .........................................................................7
1.2.5 Density.............................................................................................7
1.2.6 Dielectric Constant and Dielectric Loss Factor..............................8
1.3 Data Sources on Thermophysical Properties............................................10
1.4 Predictive Equations..................................................................................12
1.4.1 Specific Heat..................................................................................12
1.4.1.1 Specific Heat of Juices...................................................15
1.4.1.2 Specific Heat of Meats...................................................15
1.4.1.3 Specific Heat of Fruits and Vegetables..........................16
1.4.1.4 Specific Heat of Miscellaneous Products ......................16
1.4.2 Enthalpy.........................................................................................17
1.4.3 Thermal Conductivity and Thermal Diffusivity ...........................17
1.4.3.1 Thermal Conductivity of Meats.....................................20
1.4.3.2 Thermal Conductivity and Thermal Diffusivity
of Juices, Fruits and Vegetables, and Others.................22
1.4.4 Density...........................................................................................23
1.4.5 Dielectric Properties ......................................................................25
1.5 Conclusions................................................................................................28
References ...........................................................................................................30
1.1 INTRODUCTION
Thermal food processes, whether electrical or conventional, may be broadly
classified as unit operations in blanching, cooking, drying, pasteurization, sterilization,
and thawing, and involve raising the product to some final temperature
that depends on the particular objective of the process. 1 The design, simulation,
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