Fermented orange peel mitigates biogenic amines in Huangjiu: Insights into flavonoid-histidine/tyrosine decarboxylase interactions

This study aims to evaluate the inhibitory effect and molecular mechanism of orange peel (OP) and its fermented product (FOP) by Rhizopus stolonifer JP1118 on the accumulation of biogenic amines (BAs) in Chinese rice wine (Huangjiu). UHPLC-Q-TOF-MS/MS technology was utilized to analyze the differences in metabolites between OP and FOP. Huangjiu fermentation experiments were conducted to compare the effects of different OP/FOP concentrations on BAs formation, and molecular docking was used to verify the interaction between flavonoid components and BAs synthesis-related decarboxylases. The results indicated that the content of 13 flavonoid compounds in FOP was more than double that in OP. The 4 g/L FOP treatment group demonstrated the most inhibition of BAs formation, and the inhibition on histamine was particularly significant. Molecular docking results confirmed that 11 flavonoids in FOP could stably bind to histidine decarboxylase (HDC), and 10 flavonoids could stably bind to tyrosine decarboxylase (TDC). They occupy the active sites of the enzymes via hydrogen bonding and hydrophobic interactions, thereby impeding substrate binding and inhibiting the synthesis of histamine and tyramine. This research offers a technical solution for low-amine Huangjiu, references for BAs control in other fermented foods and agricultural by-product recycling, with academic and industrial significance.