In this study, the nutrients, phytochemicals (including isoflavone and ginsenoside derivatives), and antioxidant activities of cheonggukjang with different ratios (0%, 2.5%, 5%, and 10%) of mountain-cultivated ginseng (MCG) were compared and analyzed using microorganisms isolated from traditional cheonggukjang. The IDCK 30 and IDCK 40 strains were confirmed as Bacillus licheniformis and Bacillus subtilis, respectively, based on morphological, biological, biochemical, and molecular genetic identification, as well as cell wall fatty acid composition. The contents of amino acids and fatty acids showed no significant difference in relation to the ratio of MCG. After fermentation, isoflavone glycoside (such as daidzin, glycitin, and genistin) contents decreased, while aglycone (daidzein, glycitein, and genistein) contents increased. However, total ginsenoside contents were higher according to the ratio of MCG. After fermentation, ginsenoside Rg2, F2, and protopanaxadiol contents of cheonggukjang decreased. Conversely, ginsenoside Rg3 (2.5%: 56.51 → 89.43 μg/g, 5.0%: 65.56 → 94.71 μg/g, and 10%: 96.05 → 166.90 μg/g) and compound K (2.5%: 28.54 → 69.43 μg/g, 5.0%: 41.63 → 150.72 μg/g, and 10%: 96.23 → 231.33 μg/g) increased. The total phenolic and total flavonoid contents were higher with increasing ratios of MCG and fermentation (fermented cheonggukjang with 10% MCG: 13.60 GAE and 1.87 RE mg/g). Additionally, radical scavenging activities and ferric reducing/antioxidant power were significantly increased in fermented cheonggukjang. This study demonstrates that the quality of cheonggukjang improved, and cheonggukjang with MCG as natural antioxidants may be useful in food and pharmaceutical applications.
Keywords: Bacillus; antioxidant; cheonggukjang; cocktail starters; mountain-cultivated ginseng; nutrients.