Changes in histological structure and physiochemical properties of raw, cured, smoked pork loins resulting from freezing near cryoscopic temperature.

The aim of the study was to determine the effects of unintended freezing during cold storage (deep chilling conditions) and low freezing temperatures (-10 degrees C) of raw pork loins, cured and smoked, on their histological structure and some physicochemical characteristics. The experimental products after freezing at -10 degrees C, were stored at the same temperature for 0, 2, 4 and 6 days, thawed thereafter and immediately deep chilled at near cryoscopic temperature (-3 degrees C) for 0, 2, 4 or 6 days. These conditions were changing the histological structures of pork loin, the water holding capacity (WHC) was reduced by frozen storage but improved by deep chilling; the maximum shear force and energy were increased. The more the freezing at -10 degrees C was prolonged, the more unfavourable were the changes in structure, WHC and tenderness. Deep chilling at -3 degrees C after thawing of the experimental material on the other hand favourably affected the parameters measured. Freezing at -10 degrees C and deep chilling at -3 degrees C did not affect the electrophoretic picture of pork loin proteins nor the water activity. Freezing itself had no influence on WHC. Changes were due to storage.