Abstract: Crude water-soluble polysaccharides (Cpp) from 10-year-old tangerine peel were hydrolyzed with sulphuric acid and fractionated by successive ion exchange adsorption and size exclusion chromatography into three major fractions (f1-1, f2-2 and f3-2). The structures and prebiotic activities of Cpp and the fractions were compared. The results showed that f2-2 had the smallest molecular mass of 1.15 × 104 Da and was mainly composed of rhamnose, arabinose and galactose with a molar ratio of 0.21:1.00:0.25. f2-2 could promote the proliferation of Lactobacilli and Bifidobacterium, increasing their counts 3.2 and 2.9 times compared with the control group (with 1 mg/mL glucose), respectively. Cpp could only promote the proliferation of Lactobacilli significantly (P < 0.05). Compared with the control group, the addition of f2-2 significantly increased the production of propionic acid in the culture supernatant of human fecal bacteria (P < 0.05). Moreover, the addition of f1-1 or f2-2 promoted the production of butyric acid. To sum up, the polysaccharides from 10-year-old tangerine peel showed significant prebiotic characteristics, which had a close relationship the structures of the polysaccharides.

Key words: polysaccharides from tangerine peel; prebiotics; short-chain fatty acid; monosaccharide composition; probiotics