co-fermentation of juice alters chemical properties, enhances antioxidant activity, and improves gut microbiota.

Fermentation with has been shown to improve the nutritional value of juice. In this study, juice was fermented using two commercial probiotics, namely, and . The total antioxidant capacity (TAOC), viable count, chemical properties, antioxidant activity after digestion, and alterations in the gut microbiota composition of the fermented juice were investigated. After fermentation, the TAOC increased from 107.66 U mL to 126.72 U mL; viable count increased from 5.85 lg (CFU mL) to 8.17 lg (CFU mL); and the contents of total phenols, total flavonoids, proanthocyanins, four organic acids, and 29 amino acids had changed. Overall, 47 compounds were identified in the juice, 20 of which were enriched after fermentation. Furthermore, co-fermentation improved the antioxidant properties of the juice after digestion and increased the abundance of probiotics to regulate the gut microbiota. These findings illustrate the potential use of and in the co-fermentation of juice to enhance its nutritional and functional properties.