Characteristics of differential scanning calorimetry determination of thermophysical properties of meats

Abstract

Differential scanning calorimetry (DSC) was used to determine the variations in heat capacity and enthalpy of beef and pork of differing composition, and in response to different temperatures. The values in relation to changes in temperature and composition differed from published reports and were also at variance with published equations. Similar results have been observed for lamb in previous work in our laboratory. However, the above-mentioned equations can be used to predict the change in enthalpy during thawing; this is demonstrated in the present study. The study verified that the experimental results for all three types of meat can be predicted with good accuracy using just one equation which deals with temperature and moisture content only. We used pork and lamb samples and four combinations of freezing (slow or quick) with or without subsequent frozen storage, to study the possible influence of such temperature conditions on measured enthalpy and heat capacity. It was found that neither freezing or other variations in temperature significantly influence the property values of the subjects studied. As regards the melting temperature, the differences observed between DSC-based property values and those of adiabatic calorimetry may be due to differences in sample size and freezing rate. These could cause very different spatial distributions of ice crystals, leading to diverse behaviour during the thawing process. ©1998 Academic Press.