Sugar supplementation is associated with temporal profiles of metabolite accumulation and strain-specific transcriptional responses in kimchi

Sugar supplementation enhances kimchi palatability and lactic acid bacteria metabolism, yet its effects on fermentation remain underexplored. Using a defined consortium of nine kimchi-derived lactic acid bacteria, we examined fermentation following glucose, fructose, xylose, or raffinose supplementation. Sugar supplementation was associated with delayed increases of compounds, including γ-aminobutyric acid (GABA) and amino acids. Dynamic time warping estimated significant delays of approximately 15-16 days to reach control-comparable levels. Machine learning identified five metabolites (GABA, β-alanine, pyroglutamic acid, serine, and nicotinic acid) that distinguish sugar-treated from control samples (mean PRAUC >0.86 for all five). Sugar type was associated with distinct profiles, with raffinose showing prolonged sucrose abundance (mean PRAUC = 0.97) and xylose showing extensive group-specific increases, including xylitol (mean PRAUC = 1.00). Transcriptomics linked Lactobacillus strains to delayed metabolite increases and Weissella hellenica to sugar type-specific traits. These associative multi-omic findings connect sugar composition to metabolite-accumulation patterns in a defined-consortium kimchi fermentation model.