Effect of heat treatment on protein in physical and chemical properties

The myofibrillar's physical and chemical characteristics of mackerel, anchovy and sardine had been studied at 40, 50, 60, 70 and 80℃ for 30 min, respectively. The results showed that pH increased with the temperature increasing, but no obvious changes were observed at higher temperature. The brightness L*increased in comparison with raw meat, but the change of redness a* decreased after heating. Myosin, sarcoplasmic protein and action protein thermal denaturation temperature of mackerel, anchovy and sardine muscle were 42.1, 55.2, 78.3℃, 41.7, 51.6, 72.9℃, 42.8, 49.2, 75.3℃, respectively. Mackerel protein had higher thermal stability. Protein solubility and the total sulfhydryl distinctly decreased with the temperature increased, the amount of carbonyl formation increased as the temperature increased. In conclusion, the protein of three fishes denatured at 80℃ completely. The end point temperature should be controlled at 80℃ in order to achieve the purpose of thermal processing, ensuring product quality and yield, and avoiding unnecessary energy consumption.