Effects of herbal broth on fermentation characteristics, metabolomic profiles, and microbial community of kimchi during storage

This study evaluated the effects of herbal broth supplementation on the fermentation behavior, microbial community, metabolite profiles, and sensory quality of kimchi during storage. Kimchi was prepared using a general broth (GK) and two herbal broths with different concentrations of medicinal herbs (HK1, low concentration; HK2, high concentration), and stored at 4°C for 3 weeks. Herbal broth addition significantly affected fermentation dynamics: HK1 exhibited delayed fermentation, indicated by higher pH, lower titratable acidity, reduced CO2 production, and slightly lower lactic acid bacteria (LAB) counts, whereas HK2 promoted fermentation with increased LAB growth and CO2 generation. Metabolomic analysis revealed distinct metabolite profiles depending on storage period and broth type, with herbal broth kimchi associated with higher amino acid levels, while general broth kimchi showed stronger associations with xylonic acid. Microbial community analysis demonstrated shifts in dominant bacteria, including Weissella kandleri, Geobacillus stearothermophilus, and Latilactobacillus sakei, which were closely related to fermentation progression. Sensory evaluation indicated that herbal broth kimchi exhibited comparable or slightly higher scores for appearance, texture, and overall preference under controlled evaluation conditions. These results indicate that herbal broth supplementation can modulate kimchi fermentation in a concentration-dependent manner, offering a natural strategy to control fermentation and extend shelf-life.