Polysaccharide fractions from Fortunella margarita affect proliferation of Bifidobacterium adolescentis ATCC 15703 and undergo structural changes following fermentation

In this study, the relationships between the proliferation effect of polysaccharide fractions from the citrus shrub Fortunella margarita on Bifidobacterium adolescentis ATCC 15703 and their resulting structural changes were investigated. Four polysaccharide fractions, FP20, FP40, FP60, and FP80, were obtained by graded precipitation at ethanol concentrations of 20%, 40%, 60% and 80%, respectively. The results showed that polysaccharide fractions, especially FP20, FP40, and FP60, enhanced the proliferation of B. adolescentis ATCC 15703 and their effects were better than those of FP80, inulin or glucose. Moreover, acetic acid was mainly produced during fermentation. After fermentation, the molecular weight of polysaccharide fractions decreased and the tightly structural chain conformations of FP20, FP40, and FP60 changed to highly branched structures. The prebiotic effect of these polysaccharide fractions might be related to their molecular weight and chain conformation. Thus, these polysaccharides could be used as potential prebiotics.