Thermodynamic Analysis of the Freezing and Thawing of Foods: Enthalpy and Apparent Specific Heat

Abstract

ABSTRACT On the basis of the principles of freezing point depression, equations for the temperature rate of ice formation, apparent specific heat, and enthalpy were derived and expressed in terms of solids content and temperature. A unique characteristic constant for each food system can be determined experimentally from the calorimetric measurements. The new equations differ only slightly with similar equationspreviously developed by Bartlett in 1944 and by Schwartzberg in 1976. Reliability and accuracy of the methods are demonstrated with literature data for meat, fish and fruit juices. Enthalpy and apparent specific heat values for a range of temperature between 20° and 40°C and solids content between 10 and 50% are presented.