In vitro digestion and fecal fermentation behaviors of polysaccharides from Ziziphus Jujuba cv. Pozao and its interaction with human gut microbiota

This study aimed to explore the dynamic changes of structural properties of polysaccharide from Ziziphus Jujuba cv. Pozao (JPS) during in vitro digestion and fermentation as well as its impacts on gut microbiota. Gastrointestinal digestion resulted a significant decrease in the reducing sugar content (C_R), while a slight increase in the molecular weight. However, no free monosaccharide was detected. During the gut microbial fermentation, the C_R showed a trend of increasing at first and then decreasing, while the carbohydrate residue decreased with the releases of monosaccharides. Meanwhile, pH decreased along with the production of short-chain fatty acids due to the utilization of JPS. Furthermore, JPS regulated the composition of gut microbiota, such as promoting Megasphaera and unclassified_f_Veillonellaceae, while inhibiting Bacteroides, Lachnoclostridium, Parabacteroides, Sutterella, Lachnospiraceae UCG-010, and Butyicimonas; Sutterella, Megasphaera, and unclassified_f_Veillonellaceae might be the characteristic bacteria in JPS group compared to the Inulin Control group. It was also found that JPS significantly enriched the metabolic pathways of carbohydrate, energy and amino acid after fermentation. These results indicated that JPS was indigestible but played an essential role by regulating gut microbiota composition and metabolic functions, which provided a basis for the conclusion that JPS could protect intestinal barrier and enhance immunity in our previous study.