Effects of heat treatments on texture of abalone muscles and its mechanism

The objective of this study was to develop suitable heating conditions and reveal the mechanism of texture changes in abalone muscles. The milder heat treatments (60 °C-10 min and 70 °C-10 min) increased shear force and hardness of abalone muscles. However, with increased heating time or temperature (70 °C-30 min, 80 °C-10 min and 100 °C-10 min), shear force and hardness significantly decreased in abalone muscles. Decreases in the extraction rate and solubility of myofibrillar proteins (MPs), and increase in myofibrillar fragmentation index were observed in cooked abalone muscles, indicating denaturation of MPs induced by heat treatment. Heat treatment also led to protein degradation in abalone muscles as increases in dissolution rate of protein, trichloroacetic acid-soluble peptides content, soluble collagen content, and dissolution rate of hydroxyproline and glycosaminoglycan were observed. In addition, changes in miscrostructure, water content and water holding capatity (WHC) were noted in cooked abalone muscles. Correlation analysis showed that protein denaturation/degradation was responsible for changes in microstructure and WHC, which ultimately affected the textural properties of cooked abalone muscles.