Comparison of probiotic strains on microbial control and metabolite characteristics in low-salt fermented mustard green cabbage using wet vacuum impregnation

Traditional vegetable fermentation often faces challenges related to microbial inconsistency, product variability, and food safety. This study evaluated wet vacuum impregnation (WVI) as an innovative low-salt fermentation strategy for mustard green cabbage using four probiotic strains: Lactiplantibacillus plantarum HM 04-80, Lactiplantibacillus plantarum KUNN19, Limosilactobacillus fermentum KUB-D18, and Limosilactobacillus reuteri KUB-AC5. Probiotics were incorporated into 5% (w/v) brine and vacuum-impregnated into cabbage at 1 × 10 6 CFU/g, followed by fermentation at 30 °C for 15 days. Scanning electron microscopy confirmed probiotic infiltration into cabbage tissues, while final salt content remained below 1% (w/w). Microbial analysis demonstrated that WVI-assisted probiotic fermentation rapidly established lactic acid bacteria (LAB) dominance and significantly suppressed Coliform/E. coli within five days. Metabolomic profiling using NMR and HPLC revealed increased production of organic acids, short-chain fatty acids, and amino acids associated with enhanced functional properties. Among the tested strains, L. plantarum HM 04-80 and L. reuteri KUB-AC5 exhibited superior microbial control and produced bioactive metabolites, including γ-aminobutyric acid, guanine, and tyrosine. These findings highlight WVI-assisted probiotic fermentation as a promising precision fermentation approach for developing low-salt pickled vegetables with improved microbial safety and functional quality.