On the Thermal Properties of Frozen, Refrozen and Freeze Drying Porcine Longissimus dorsi

摘要

Modulated Differential Scanning Calorimetry (Modulated DSC) was used to investigate the protein denaturation characteristics of Longissimus dorsi muscle at different conditions; fresh, frozen and refrozen. Meat was also freeze drying to determinate its thermal properties. The thermograms indicated three exothermic peaks between 45-85°C, corresponding to denaturation of myosin (peak 1), sarcoplasmic proteins (peak 2) and actin (peak 3). Refrozen process significantly affected denaturation enthalpy reducing the value from 2.69-2.21 J g-1. Samples submitted to freeze drying showed a single sharp peak centered about 81.85°C with a similar trend in regards to denaturation enthalpy. In the case of heat Capacity (Cp), the maximum change was observed at 80°C with a reduction following the order; fresh, frozen and refrozen. This phenomenon was also found for freeze drying samples however, the single broad change was in the temperature range of 40-100°C. From these results, it is concluded that moisture content plays an important role in the thermal properties of meat.