Isolation and structural characterisation of okara polysaccharides

Molecules. 2012 Jan 13;17(1):753-61. doi: 10.3390/molecules17010753.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbohydrate Conformation
  • Glycine max / chemistry*
  • Methylation
  • Monosaccharides / chemistry
  • Plant Extracts / chemistry
  • Plant Extracts / isolation & purification*
  • Polysaccharides / chemistry
  • Polysaccharides / isolation & purification*
  • Soy Foods*

Substances

  • Monosaccharides
  • Plant Extracts
  • Polysaccharides