Comparative analysis of dietary fibers from grapefruit peel prepared by ultrafine grinding: Structural properties, adsorption capacities, in vitro prebiotic activities

Ultrafine grinding treatment was used to treat grapefruit peel from Shatianyou, Majiayou, Dabumiyou and Jinggangmiyou, subsequently structural properties and adsorption capacities of extracted soluble dietary fibers (SDFs) were comparatively analyzed, moreover SDF from untreated Dabumiyou (D-SDF) and SDF from Dabumiyou treated with ultrafine grinding (UD-SDF) were selected for in vitro prebiotic activity determination. The structural analysis exhibited that all SDFs manifested spectral characteristics of typical polysaccharides and showed a typical cellulose I-type structure, ultrafine grinding treatment broke chemical bonds between molecules, leading to a decrease in crystallinity, further reduced thermal stability of SDFs. The pectin content of SDFs were enhanced after modification, which may influence functional properties of SDFs. Moreover, SDFs from Dabumiyou showed better adsorption capacities for water molecule, oil molecule and cholesterol molecule. Compared to D-SDF, UD-SDF could effectively promote bacteria proliferation and stimulate probiotic strains to produce more short-chain fatty acids. This study was beneficial to better understanding physicochemical properties of SDFs extracted from different grapefruit peel by ultrafine grinding treatment and encouraged the use of grapefruit peel SDF in products with prebiotic properties.