Composition and Physicochemical Properties of Dietary Fiber Extracted from Residues of 10 Varieties of Sweet Potato by a Sieving Method

Dietary fiber (OF) was extracted from sweet potato residues after starch isolation of 10 varieties using a sieving method. The proximate composition of sweet potato residues, chemical composition, monosaccharide composition, and physicochemical properties of OF were investigated. The average yield and OF content of OF products from 10 sweet potato varieties were 9.97 and 75.19%, respectively. Average contents of cellulose, lignin, pectin, and hemicellulose were 31.19, 16.85, 15.65, and 11.38 g/100 g of dry matter in OF products, respectively. The relative monosaccharide contents of OF were in the order glucose > uronic acid > galactose > arabinose > xylose > rhamnose > mannose. Swelling capacity, water-holding capacity, oil-holding capacity, and glucose absorption capacity determinations of the OF of sweet potato varieties had respective ranges of 8.11-12.56 mL/g, 3.54-6.15 g/g, 1.43-2.48 g/g, and 0.54-1.27 mmol/g. OF of the 10 varieties had clear differences in characteristics and physicochemical properties.