Biotransformation of citrus fruits phenolic profiles by mixed probiotics in vitro anaerobic fermentation

Citrus fruits (CFs) were abundant in polyphenols (PPs). This study aimed to assess the effect of mixed lactic acid anaerobic fermentation-based biotransformation on CFs phenolic profiles and antioxidant activity. Citrus PPs were metabolized into small molecular phenolics. Moreover, the total SCFAs, acetic acid and butyric acid were remarkably increased in CFs supernatant ( p  < 0.05), and the populations of Lactobacillus bulgaricus and Lactobacillus acidophilus significantly increased ( p  < 0.05). Finally, fermented CFs exhibited strong antioxidant activity by reducing ROS fluorescence intensity induced by lipopolysaccharide and increasing mitochondrial membrane potential in Caco-2 cells. These findings indicate that citrus PPs microbial derivatives could act as key active ingredients in functional foods.