Interactions of heat-induced myosin with hsian-tsao polysaccharide to affect the fishy odor adsorption capacity

The interaction mechanism of hsian-tsao polysaccharide (HTP) with unique gel-promoting and biological activity for improving the gel properties of surimi was not clarified. This study investigated the effects of HTP on heat-induced structural changes and the adsorption capacity of myosin to fishy odor compounds (hexanal, heptanal, nonanal, and 1-octen-3-ol). HTP concentration and heating ways greatly affected the physicochemical properties of myosin. Adding hydrophilic HTP covering the myosin surface aided in unfolding the structure of myosin and further disturbed the myosin aggregation with surface hydrophobicity decreased and total sulfhydryl contents increased. The main physical forces arising from hydrogen bonding and electrostatic interactions contributed to forming HTP-myosin complexes under setting (40 °C, 30 min), whereas cross-links occurred by enhanced hydrophobic interactions forming insoluble HTP-myosin complexes under two-step heating (40 °C, 30 min; 90 °C, 20 min), indicative of decreased solubility and increased turbidity, as evidenced by zeta potential, FTIR, fluorescence and UV–vis spectra, and fluorescence microstructure. This resulted in the transformation of secondary structure of myosin from α-helix to β-sheet with the increase of HTP. Furthermore, HTP interacting with myosin reduced the fishy odor binding capacity of myosin thus promoting the release during processing, as demonstrated by HS-SPME-GC. The findings provided new insight into the mechanism of regulating the fishy odor binding ability of myosin by application of HTP.