Effect of Sous Vide on the Structure of Myofibrillar Protein from Penaeus vannamei

This study aimed to investigate the effects of sous vide (SV) on the structure of myofibrillar protein (MP) in Penaeus vannamei. MP was subjected to SV cooking at different combinations of temperature (40, 50, 60, 70, and 80 ℃) and time (5, 10, and 15 min). Non-treated MP served as control. The samples were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and their solubility, surface hydrophobicity, carbonyl content, total sulfhydryl content, Fourier transform infrared spectroscopy (FTIR), and Raman spectra were evaluated. The results showed that with increasing processing temperature and time, the carbonyl and total sulfhydryl content, surface hydrophobicity, and particle size of MP increased, and the solubility decreased in general. This indicates that shrimp MP underwent oxidative denaturation during SV processing, with structural changes such as deconstruction, reorganization, and aggregation, and that the denaturation point was reached after 5 min at 50 ℃. The increase in total sulfhydryl contents and particle sizes together indicate that disulfide bonding was not the major cause of MP aggregation during the process. This conclusion was further supported by the altered intensity of myosin heavy chain bands in SDS-PAGE, as well as the initial increase and then decrease in α-helix content and the increase in β-sheet content as characterized by FTIR and Raman spectroscopy.