Strain-Specific Lactic Acid Bacteria Fermentation of Kiwifruit Juice: From Flavor Optimization to In Vitro Gut Microbiota Modulation

The deep processing of kiwifruit remains an urgent challenge. In this work, we evaluated the effects of seven lactic acid bacteria (LAB) strains on the overall quality of the kiwifruit juice. All strains exhibited robust growth, and LAB fermentation markedly improved the flavor profile of the juice, with the M29 group best preserving the characteristic kiwi fruit aroma. Sensory analysis further revealed that M29 and LB22 particularly enhanced the fruity sensory notes. In vitro fecal fermentation demonstrated that fermented kiwifruit juice increased the relative abundance of beneficial genera (e.g., Lactobacillus and Faecalibacterium) while significantly reducing potential pathogens including Enterobacter. Additionally, short-chain fatty acids, especially propionate and butyrate, increased significantly. Functional prediction analysis further suggested shifts in the carbohydrate and amino acid metabolism. Overall, this work provides theoretical evidence for the dual regulatory role of probiotic fermentation in improving both the flavor and the gut microbiota of kiwifruit juice.