Metabolic Remodeling and Flavor Enhancement of Mulberry Juice Through Lactic Acid Bacteria Fermentation: A GC-IMS and Untargeted Metabolomics Approach

Fresh mulberry juice (MJ) faces industrial challenges due to its short shelf life and inconsistent flavor. This study innovatively addressed these limitations by applying L. plantarum (LP) and L. fermentum (LF) fermentation to MJ, combining non-targeted metabolomics and GC-IMS to systematically elucidate metabolic remodeling and flavor enhancement. Fermentation (36 h) achieved LAB counts > 7 log CFU/mL, significantly reducing soluble solids and pH from 15.00 to 13.90, 14.01 °Brix and 3.74 to 3.21, 3.13, respectively. In contrast, the bioactive compounds as detected by the increase in flavonoids and phenolics from 254.85 mg/100 g to 289.36, 291.39 mg/100 g and 286.21 mg/100 g to 294.55, 302.2033 mg/100 g, respectively. Anthocyanin content as high as 165.88 and 156.69 mg/L. Metabolomics identified enriched amino acid pathways, and GC-IMS revealed unique flavor profiles. The study fills a research gap by demonstrating LAB fermentation’s dual role in extending MJ’s shelf life and improving its functional nutritional quality, offering a novel strategy for functional food development.