Effects of complex polysaccharides by Ficus carica Linn. polysaccharide and peach gum on the development and metabolites of human gut microbiota

Both Ficus carica Linn. polysaccharide and peach gum had beneficial effects on human gut microbiota. However, their complex polysaccharides have never been studied during the fecal fermentation in vitro. Therefore, this study investigated the effects of Ficus carica Linn. polysaccharide (FCPS), peach gum polysaccharide (PGPS) and their complex polysaccharides on fecal fermentation characteristics and gut microbiota composition in vitro. The changes of pH, gas production and short-chain fatty acids (SCFAs) in the metabolites were measured at 0, 6, 9, 12 and 24 h under anaerobic conditions. The changes of gut microbiota were measured at 24 h. The results of metabolite determination showed that FCPS and FCPG2_1 had strong acid production, pH reduction and gas production ability, while the PGPS had poor effect. The results of gut microbiota analysis showed that Firmicutes, Bacteroidetes and Proteobacteria were the dominant phyla in the fermentation process, and the ratio of Firmicutes to Bacteroidetes was the lowest in the FCPG1_1. At the genus level, the promoting effects of these five polysaccharides on different genera were different. FCPS notably augmented the proliferation of Bacteroides and Phascolarctobacterium. Similarly, FCPG1_1 significantly enhanced the growth of Faecalibacterium and Paraprevotella. Furthermore, FCPG2_1 was responsible for an upsurge in the proliferation of the Lachnospiraceae_NK4A136_group, whereas PGPS proved excellent in stimulating Roseburia's growth. In summary, complex polysaccharides and FCPS were better, and they had potential anti-obesity effects. This study had practical significance for the development of functional food and dietary intervention.