During sweet potato starch production, large amounts of residues are produced as by-product, containing about 50% dietary fiber. In order to investigate the modulatory effect of this sweet potato dietary fiber (SPDF) on human microbiota, SPDF was extracted from sweet potato using ultrasound-assisted enzymatic extraction method with the yield of 21.6 %. The chemical properties of SPDF, including water-holding capacity, oil holding capacity and swelling capacity was determined as 8.5 g/g, 6.1 g/g and 7.3 mL/g, respectively. Scanning electron microscope was used to investigate the surface and microstructure of the SPDF. In addition, a mixed-culture fermentations with rat faecal inoculate was used to elucidate the effects of SPDF on the diversity of intestinal microbiota. Our results showed that digested SPDF mediated significant increases in concentrations of Bifidobacterium genus (3.88×109 cfu/mL vs 6.71×108 cfu/mL) and Lactic acid bacteria (5.81×108 cfu/mL vs 2.56×106 cfu/mL), whereas significantly decreased Enterobacillus (1.28×107 cfu/mL vs 5.6×108 cfu/mL), Enterococcus (6.27×105 cfu/mL vs 2.12×106 cfu/mL), and Clostridium perfringens (3.71×106 cfu/mL vs 8.24×107 cfu/mL) compared to the negative control. The prebiotic index and B/E value were also significantly increased by 56.1% and 150%, respectively, indicating beneficial prebiotic effects of the SPDF. Our findings supported the potential of dietary fiber from sweet potato as prebiotic food products aimed at improving gastrointestinal health.

Impact of dietary fiber from sweet potato fermented in vitro on the diversity of gut microbiota

256th National Meeting (2018)

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