Abstract:In this study, the effects of different concentrations of linoleic acid (0, 10, 20, and 50 mmol/L) for mediating oxidation on the gel strength, gel water retention, and gel water distribution of golden pompano myofibrillar protein through constructing a linoleic acid-mediated golden pompano fish flesh oxidation system. The results showed that the effect of oxidation on the gel properties was most obvious at a linoleic acid concentration of 10 mmol/L, with the centrifugal loss and cooking loss reaching the smallest (5.39% and 5.94%, respectively), while the gel strength reaching the maximum value (333.24 g). With the increase of linoleic acid concentration, the carbonyl content of myofibrillar protein increased from 2.86 nmol/mg to 6.65 nmol/mg, and the total sulfhydryl group content decreased from 63.58 nmol/mg to 58.69 nmol/mg. The molecular weight change revealed that with the increase of the degree of protein oxidation, the surface hydrophobicity and intrinsic fluorescence intensity showed a tendency of initial increase then decrease, indicating that moderate linoleic acid oxidation (≤10 mmol/L) could cause protein molecules to unfold moderately, forming a gel product with good textural properties and high water retention; whilst excessive linoleic acid oxidation (>10 mmol/L) caused excessive oxidation of proteins, leading to cross-linking of protein molecules and aggregation of protein molecules, thereby declining the textural properties of protein gels. This study elucidates the effects of linoleic acid oxidation on the post-processing characteristics of golden pomfret and promote the development of the golden pomfret industry.
