Metabolite profiling of Makgeolli for the understanding of yeast fermentation characteristics during fermentation and aging

- GC-MS based metabolomics study to understand Makgeolli fermentation is described.
- Metabolite changes including sugars, organic acids, amino acids, and polyols were observed during fermentation.
- Pattern recognition methods showed clear metabolic differences among Makgeolli according to the fermentation periods and yeast strains.
- This methodology is a valuable tool for monitoring Makgeolli fermentation and evaluating the fermentative characteristics of yeast strains.

Makgeolli is a traditional fermented rice wine in Korea containing complex mixture of metabolites. GC-MS datasets coupled with multivariate statistical analysis were used for the first time to investigate metabolic changes in Makgeolli during fermentation and aging, and to assess the fermentative behaviors of yeast strains. Makgeolli fermentation progressed very quickly during the early fermentation period, whereas Makgeolli metabolites barely changed during the aging period for up to 70 days. During alcohol fermentation, decreased levels of glucose and phosphoric acid, along with increased levels of the other identified metabolites were observed. The levels of tryptophan, myo-inositol, malic acid, tyrosine, ornithine, leucine, glutamic acid, glutamine, citric acid, and 2-hydroxyglutaric acid in Makgeolli with the Saccharomyces cerevisiae, as well as the levels of glycerol, lactic acid, glycine, 4-hydroxyphenylethanol, and erytritol in Makgeolli with the Saccharomyces coreanus had the highest significance. This study highlights the applicability of GC-MS based metabolite profiling for monitoring Makgeolli fermentation and evaluating the fermentative characteristics of yeast strains.

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