Abstract: The effect of irradiation on pork muscle protein degradation was investigated. Low-dose irradiation (3 kGy) was applied on fresh pork hindquarter meat and the meat was evaluated for small molecular polypeptides and amino acid compositions derived from the degradation of various pork muscle proteins. The results showed that the contents of Leu, Ile, Met, Ser, Glu, Cys and Thr in irradiated samples decreased significantly compared to the control samples (P < 0.05), while the contents of Vla, Pro were not significantly changed after irradiation. The degradation degree of different muscle proteins during irradiation and their contribution to the formation of small molecular polypeptides were different. A total of 104 small molecular polypeptides (< 3 kDa) were produced in the irradiated pork meat, more than 50% of which were derived from myofibrillar proteins, 30.7% from titin, nebulin, and troponin T and I, and 22.2% from desmin, myotilin, LIM domain-binding protein 3 and actinin-associated LIM protein 1a. The generation of these small molecular polypeptides suggested that irradiation could influence the taste of meat products.

Key words: γ-irradiation, amino acid composition, polypeptides, myofibrillar protein, muscle structural protein