Abstract:The mechanism of action of the ternary complex of polyphenols, polysaccharides, and proteins on myofibrillar protein was explored, and its application potential in the antifreeze of aquatic products was evaluated. In this study, sinapic acid, chitosan and collagen were used as raw materials, and the preparation conditions of sinapic acid grafted chitosan were screened by single factor test. The effect on turbidity, endogenous fluorescence spectra, and the secondary structure of tilapia myofibrillar proteins at room temperature was investigated, along with UV-Vis spectra and SDS-PAGE under freezing conditions. The results showed that the optimal preparation conditions of sinapic acid grafted chitosan were pH 6.5, molecular weight of chitosan 1 ku, reaction time 18 h, the ratio of sinapic acid to chitosan 1:1, and the obtained grafting degree 428.14 mg SAE/g. At room temperature, 0.4%SA-g-CS complex reduced the endogenous fluorescence intensity and α-helical structure of myofibrillar protein by 3.49% and 27.45%, respectively, and the turbidity, β-sheet and random coil increased by 39.09%, 30.43% and 53.85%, respectively. During the freezing process, the ultraviolet absorption peak intensity of myofibrillar protein enhanced, the protein band became thicker. Therefore, the sinapic acid-chitosan-collagen complex prepared in this study can effectively delay the oxidative denaturation of tilapia myofibrillar protein during the freezing process, providing a theoretical basis for the application of polyphenols, polysaccharides and protein ternary complex in the freezing resistance of aquatic products.
