From Baijiu by-product to bioactive goldmine: The health-promoting potential of Jiuzao extracts

Jiuzao is the primary by-product of the Baijiu industry, and contains numerous water-soluble nonvolatile active ingredients (WSNVAIs). This study first assessed the antioxidant activity of Jiuzao extracts (JEs). Results indicated that enzymatic hydrolysis increased the polyphenol, polypeptide, and alkaloid levels, enhancing the antioxidant capacity of JEs. Moreover, soy-sauce-flavored JEs exhibited excellent comprehensive antioxidant activity owing to the higher total polyphenol and total amino acid content, as well as the synergistic effect of multiple metabolites. The WSNVAIs in JEs were analyzed using widely targeted metabolomics, identifying 1,556 metabolites, of which 1,493 were newly found in Jiuzao. Metabolomics analysis identified 6 key metabolic pathways and 47 biomarkers for distinguishing different JEs, primarily involving amino acid, starch, and sucrose metabolism. Finally, the potential pharmacologically active ingredients of metabolites were explored using existing databases, further demonstrating the health-promoting potential of JEs. This study systematically decoded the WSNVAIs in JEs, providing a theoretical basis for developing high-quality derivatives. • A total of 1,493 metabolites were first reported in Jiuzao extracts (JEs). • The antioxidant activity and nonvolatile components of JEs were studied. • Higher polyphenol and amino acid levels boost JEs' antioxidant activity. • Enzymatic process could promote the release of polyphenols, peptides and alkaloids. • Discovered 64 active ingredients for 328 diseases and 103 peptides with 21 functions.