Widely targeted metabolomics and flavoromics reveal the effect of Wickerhamomyces anomalus fermentation on the volatile and nonvolatile metabolites of black garlic juice

Black garlic has a variety of biological activities, but many consumers cannot accept it because of the garlic odor and the bitter taste. In this study, fermentation with yeast Wickerhamomyces anomalus was adopted to improve the flavor of black garlic juice. Although fermentation reduced antioxidant activities, the garlicky odor and bitter taste were weakened. Metabolomic analysis revealed 141 metabolites were significantly differentially regulated. The upregulated metabolites were mainly related to nucleotides, organic acids and their derivatives, while the downregulated metabolites were mainly related to amino acids, lipids and their derivatives. Flavoromics analysis revealed that 137 metabolites were significantly differentially regulated, particularly garlicky and pungent volatiles were significantly downregulated. Correlation analysis indicated that esters are most closely related to nonvolatile metabolites, and lipids degradation was significantly correlated with volatiles. The results indicated that W. anomalus fermentation is an effective strategy to improve the flavor of black garlic juice.