Extrusion or alkaline hydrogen peroxide prior to enzymatic hydrolysis by a carbohydrase mixture improves techno-functional properties of okara

Abstract

Okara is a soyfood processing by-product with high level of insoluble dietary fibres. It is often underutilised due to undesirable effects on food texture. To improve hydration properties and increase soluble fibre, okara was treated by extrusion (ET) or alkaline hydrogen peroxide (AHP) and then, each modified sample was hydrolysed by a carbohydrase mixture (EH). Other physical, chemical, and techno-functional properties were studied. ET + EH increased low-molecular-weight fibres and oil absorption and holding capacity and reduced water absorption and holding capacity. AHP + EH increased soluble fibres, sugars, water absorption and holding capacity, swelling capacity, and protein solubility in water and decreased oil absorption and holding capacity and solids stability in water. Both changed microstructure, cellulose crystallinity, and colour. This study provided new insights into the transformation of okara residue into a value-added ingredient.