Abstract:

The effects of protein degradation on the spoilage progress of chilled tilapia fillets were measured by proteolytic bacteria, proteolytic compounds, protein solubility, the SDS-PAGE change patterns of myofibrilar protein and sarcoplasmic protein. The results showed that: the changes of proteolytic bacteria, pH and amino nitrogen met well the protein degradation progress of muscle. When proteolytic bacteria kept less than 6.10 logCFU/g, pH was in week acidity, amino nitrogen stayed no many changes, and the SDS-PAGE pattern of myofibrilar protein and sarcoplasmic protein had no evident changes. While proteolytic bacteria increased equal and more than 7.60 logCFU/g, pH was in neutrality and week alkalinity, amino nitrogen increased rapidly, and the protein strip of SDS-PAGE pattern became outspread and breakdown, the protein degradation strengthened continuously. It was a very important spoilage indication in the SDS-PAGE pattern of myofibrilar protein when third strip in the region of 45→29 kDa disappeared, and new strips in the region of ≤29 kDa appeared. These results were provided a theoretical basis for further study on screening out specific protein during protein degradation to indicate the process of quality deterioration in fish.