title: Isolation and structural characterisation of okara polysaccharides.
abstract: Okara is a byproduct generated during tofu or soymilk production processes. Crude polysaccharide (yield 56.8%) was isolated by removing fat, protein and low molecular weight carbohydrates from initial okara. Crude okara polysaccharide was further divided into four soluble fractions and an insoluble residue fraction by extracting with 0.05 M EDTA + NH(4) oxalate, 0.05 M NaOH, 1 M NaOH and 4 M NaOH, with yields of 7.7%, 3.6%, 20.7%, 16.0% and 27.9%, respectively. Arabinose, galactose, galacturonic acid, xylose and glucose (only for the insoluble fraction) were the major constituent sugars. The primary sugar residues of okara polysaccharides were 1,4-linked β-galactopyranose, 1,5- and 1,3-linked α-arabinofuranose, 1,5-linked α-xylofuranose, 1,2-linked, 1,2,4-linked and terminal α-rhamnopyranose (or fucopyranose), and 1,4-linked β-glucopyranose (only for the insoluble fraction), indicating okara polysaccharides might contain galactan, arabinan, arabinogalactan, xylogalacturonan, rhamnogalacturonan, xylan, xyloglucan and cellulose.
authors.affiliation: School of Food Science, Henan Institute of Science and Technology, Xinxiang 453003, Henan, China. libowuxi@yahoo.com.cn
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Fei
authors.initials: F
authors.lastname: Lu
authors.forename: Haijuan
authors.initials: H
authors.lastname: Nan
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
mesh_terms: D002236:Carbohydrate Conformation; D008745:Methylation; D009005:Monosaccharides / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification*; D011134:Polysaccharides / Q000737:chemistry / Q000302:isolation & purification*; D045730:Soy Foods; D013025:Glycine max / Q000737:chemistry*
chemical_list: D009005:Monosaccharides; D010936:Plant Extracts; D011134:Polysaccharides