Abstract: In this study, tilapia fillets were used as raw materials to investigate the cooking loss rate, color, texture characteristics, sensory evaluation and microstructure changes under different cooking conditions, as well as the myofibrillar proteins content, total thiol group content, Ca2+-ATPase activity and its secondary structure changes were examined. The results showed that the cooking loss rate of tilapia fillets increased to varying degrees with the extension of heating time under different cooking temperatures, and lower cooking loss at 90°C. The values of L* and b* increased and a* decreased. The color of the fish fillets after being boiled for high-temperature short-term was better. The hardness, adhesiveness and chewiness gradually increased with time at 50℃, and decreased as a whole at 60℃ and above. The texture properties of fish meat treated at 80°C and 90°C were relatively better. Scanning electron microscopy results showed that the tissue structure of the fish became loose during the cooking process, and the muscle fiber bundle gap was obvious. With the increase of temperature at the same time, the muscle fiber bundle gap gradually increased, and the damage became more serious. However, high-temperature short-term heating will cause less damage to the tissue structure of the fish. Sensory evaluation results are basically consistent with the trend of various quality indicators. The myofibrillar proteins content, total thiol group content and Ca2+-ATPase activity all decreased significantly (P<0.05), the degree of protein denaturation is smaller under the condition of low-temperature long-term heating; The proportion of myofibrillar protein α-helix and β-turn were decreased, and the proportion of β-sheets and random coils were increased. The content of α-helix and β-turn under the condition of low-temperature long-term heating is higher than that of high-temperature short-term heating. In summary, considering the edible quality and actual production efficiency, high-temperature short-term cooking are more suitable cooking conditions for tilapia fillets. And the quality of fish fillets is better when cooked at 80-90 ℃ for 6-9 min.

Key words: tilapia, boilingr, quality, myofibrillar protein