Effects of Different Freezing Rates on the Quality Changes in Cooked Crayfish (<i>Procambarus clarkia</i>) Meat during Frozen Storage (-20°C)

Abstract

Changes in physical, chemical, microbiological and sensory qualities of cooked crayfish (Procambarus clarkia) meat, treated at different freezing rate (-30°C,CPF; -60°C,ULTF; -196°C,LNM), were investigated during storage at -20°C for up to 6 months. pH value increased in all treatments with the sharp reduction after 3 months. Increase in weight loss of LNM was slower than that of CPF and ULTF cooked crayfish. During frozen storage, thiobarbituric acid value (TBA value) fluctuated in all treatments, but lipid oxidation did not affect the quality of crayfish meat because of its lower fat contents. Total volatile basic nitrogen (TVB-N) increased with storage time, with the reduction of TVC and sensory score. Freezing rates could not cause significant changes in chemical qualities (pH value, total volatile basic nitrogen, thiobarbituric acid value), sensory quality and microbiological quality for all three treatments during storage. In spite of decrease of quality of cooked crayfish meat in all treatments, good edibility was kept throughout the storage.