Composition and physicochemical properties of dietary fiber extracted from residues of 10 varieties of sweet potato by a sieving method.

Dietary fiber (DF) 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 DF were investigated. The average yield and DF content of DF 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 DF products, respectively. The relative monosaccharide contents of DF 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 DF 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. DF of the 10 varieties had clear differences in characteristics and physicochemical properties.