Dynamic modulation of nutritional and flavor profiles in Aronia melanocarpa juice during fermentation with Lactobacillus casei 139

The dynamic regulatory mechanisms by which Lactobacillus casei 139 fermentation modulates the nutritional components and flavor characteristics of Aronia melanocarpa (Michx) Elliott juice were investigated through a systematic evaluation of temporal changes in nutritional and flavor profiles during fermentation. The results indicated that the viable cell density peaked at 6.01 log CFU/mL within 24 h. During fermentation, the pH of A. melanocarpa juice initially increased slightly within 48 h before gradually decreasing, while titratable acidity consistently decreased, reflecting the metabolic activity of Lactobacillus casei 139. Concurrently, total sugar content exhibited a decline followed by a leveling off to a steady state. It was found that the contents of total phenolic and flavonoid contents decreased initially, while the color difference a* first decreased, then increased. Combined electronic nose and sensory analyses revealed that fermentation enhanced aroma complexity, and mitigated astringency by promoting aromatic compound accumulation. The research confirms that fermentation with strain L. casei 139 can effectively improve both the sensory quality and nutritional value of fermented A. melanocarpa beverages.