Physicochemical, functional, and biological properties of water-soluble polysaccharides from Rosa roxburghii Tratt fruit

Water-soluble polysaccharides (RTFP) were extracted from Rosa roxburghii Tratt fruit by hot water method. The physicochemical, functional, and hypoglycemic properties of RTFP were investigated. The results revealed that RTFP mainly contained carbohydrates (63.79 +/- 0.73%, g/g), uronic acids (14.8 +/- 0.06%, g/g), and proteins (4.10 +/- 0.58%, g/g). RTFP was composed of arabinose, galactose, glucose, mannose, xylose, and fucose with molar percentages of 33.8, 37.3, 20.7, 1.74, 3.43, and 2.95%, respectively. Functional analyses indicated that RTFP had good oil-holding capacity, foaming properties, and emulsifying capacity. The rheological results showed that RTFP exhibited typical shear-thinning behavior and viscoelastic properties influenced by sample concentration, temperature and inorganic salt. Additionally, RTFP exhibited favorable inhibitory activities against alpha-glucosidase in a mixed inhibition type, and against alpha-amylase in an uncompetitive inhibition type. These results suggest that RTFP can be exploited as a multi-functional additive or hypoglycemic agent in foods, pharmaceuticals and cosmetics.