Effects of yeast inoculation on community, metabolites, and flavors in ganjang, a traditional Korean fermented soy sauce

초록

We investigated the effects of defined yeast starters on ganjang fermentation using batches inoculated with Debaryomyces hansenii, Wickerhamomyces anomalus, and/or Wickerhamiella versatilis in combination with Tetragenococcus halophilus. Absolute quantification showed that T. halophilus dominated the bacterial community and was associated with early acidification, whereas yeasts persisted at low abundance and became readily detectable only after doenjang-meju removal. Yeast inoculation had minimal effects on pH, microbial community structure, and primary metabolite profiles. In contrast, volatile organic compound (VOC) profiles clearly differentiated yeast-inoculated batches in a fermentation stage-dependent manner; Wi. versatilis and D. hansenii were associated with more diverse VOC profiles at 60 and 240 days, respectively. Notably, Wi. versatilis was associated with distinct VOC profiles despite its low abundance. These findings suggest the stage-specific roles of defined yeasts and support targeted yeast selection as a strategy to modulate VOC profiles in high-salinity ganjang fermentation.

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