Unraveling the improvement of (-)-epigallocatechin-3-O-gallate marination against salt reduction-induced quality deterioration of dry-cured grass carp: Mechanistic links among antioxidation, bacterial community rebalance, and flavor evolution control.

The improving effects and underlying mechanism of EGCG marination against salt reduction-induced quality deterioration of dry-cured grass carp (DCGC) were unraveled. Results showed that ≥500 mg/L EGCG marination contributed to water activity decline, inhibiting spoilage bacterial growth (Streptococcus parauberis, Carnobacterium maltaromaticum, Brochothrix, unclassified Enterobacteriaceae, Vibrio, etc.) and increasing flavor-contributing bacterial richness (mainly some lactic acid bacteria, Staphylococcus, and Psychrobacter species). The bacterial community structural rebalance and antioxidation of EGCG alleviated peroxidation and deterioration of lipids and proteins (carbonyl, malondialdehyde, acid value, and total volatile basic nitrogen decline), resulting in pH and nitrite residue reduction, and further decreasing fishy off-odorants production (1-octen-3-ol, 1-penten-3-ol, hexanal, 1-hexanol, triethylamine, etc.) and improving characteristic aroma generation (3-hydroxybutan-2-one, 3-methyl-1-butanol, 2-methyl-1-propanol, etc.). Both enhanced physicochemical properties and reconstructed aroma improved salt reduction-induced sensory deterioration of DCGC. This study could help understand the quality-improving mechanism of polyphenols on salt-reduced aquatic foods and provide support to cured/fermented product development.