Dynamic digestion of tamarind seed polysaccharide: Indigestibility in gastrointestinal simulations and gut microbiota changes in vitro

Tamarind (Tamarindus indica L.) seed polysaccharide (TSP) is widely used due to its excellent physico-chemical and biological properties. In this study, therefore, the dynamic digestion and fermentation of TSP in vitro were evaluated with the effect on gut microbiota composition estimated by high-throughput sequencing. The results of gastric and small intestinal digestions showed the molecular weight of TSP kept stable with only small production of reducing sugar. During the fermentation, however, the total carbohydrate kept decreasing and short-chain fatty acids (SCFAs) maintained growing. Compared to the control (distilled water), the contents of total and non-branched SCFAs were higher after fermentation, esp. propionic and butyric acids, and the gut microbiota composition was also modified with inhibited enteropathogenic (genera Escherichia-Shigell and Dorea) and promoted beneficial (genera Lactobacillus, Parabacteroides, Prevotella and Faecalibacterium) bacteria, suggesting TSP has potential prebiotic functions including anti-obesity and anti-inflammation, as well as maintaining intestinal epithelial barrier.