Hydrolysis kinetics of okara and characterization of its water-soluble polysaccharides

As a part of a study of reuse of waste okara, the kinetic mechanism of okara hydrolysis and the properties of the water-soluble polysaccharides (WSP) extracted were investigated. Okara was hydrolyzed by being autoclaved at pH 4.5 in two volume of water with or without a chelator such as hexametaphosphate. Okara hydrolysis proceeded by surface degradation mechanism without a chelator. Characterization of WSP suggested that the "egg-box regions" in okara were susceptible to degradation by a chelator and that the "non-egg-box regions" contained WSP linked with hydrophobic proteins. WSP with a molecular weight of more than 10(5) and the amount of protein bound to the polysaccharides seemed to govern their emulsifying characteristics.