Myosin affects the structure and volatile flavour compounds binding of G-actin in grass carp

The effects of myosin (0, 0.2, 0.4, and 0.6 mg mL(-1)) on the protein structure and volatiles adsorption capacity of G-actin from grass carp were investigated. The results showed that the myosin addition increased the surface hydrophobicity and sulfhydryl contents of G-actin. The Raman spectroscopy analysis showed that the alpha-helix and beta-sheet of G-actin were converted into beta-turn and random coil with 0.2 and 0.4 mg mL(-1) of myosin, while only the beta-turn content increased with 0.6 mg mL(-1) of myosin. The GC-MS analysis indicated that with myosin addition, the adsorption capacities of G-actin on alcohols (1-pantanol, 1-hexanol, 1-octen-3-ol, and 1-octanol) and ketones (2-pentanone, 2-heptanone, 2-octanone, and 2-nonanone) were enhanced; meanwhile, the binding of G-actin to aldehydes (pentanal, hexanal, octanal, and nonanal) was weakened. It was probably due to the formation of actomyosin, and also the excess myosin when treated with high concentrations (0.4 and 0.6 mg mL(-1)) of myosin.