Comprehensive multi-omics analysis of secondary distillate from fermented Huangjiu residue: Insights into flavor formation and microbial dynamics.

Huangjiu residue distillate, or Zaoshao, is a traditional Chinese liquor produced from the fermentation and distillation of Huangjiu lees. This study investigates the fermentation mechanisms and flavor formation of secondary Zaoshao, derived from the second round of Huangjiu lees fermentation, using flavoromics, amino acid and organic acid profiling, and metagenomics. Flavoromics identified ethyl octanoate, ethyl decanoate, ethyl dodecanoate, ethyl hexadecanoate, and ethyl (Z)-octadec-9-enoate as key flavor compounds. Amino acid and organic acid profiling showed continuous increases in amino acid content and significant changes in organic acids during fermentation. Metagenomics identified 9 dominant genera and 10 key species, with Saccharomyces, Saccharopolyspora, Aspergillus, Streptomyces, and Bacillus playing crucial roles in fermentation and flavor formation. These findings provide insights into microbial community functions and offer a foundation for regulating microbial consortia to enhance the flavor quality of secondary Zaoshao.