Effects of enzymatic/alkali protein removal and particle size reduction on physicochemical and functional characteristics of okara dietary fibre

Abstract

The combined effects of enzymatic/alkali protein removal treatments and superfine grinding on the characteristics of okara dietary fibre (DF) were investigated. Protein removal could effectively increase the obtained DF content and further enhance water‐holding capacity (WHC), swelling capacity (SC) and oil‐holding capacity (OHC). The DF with Alcalase treatment and superfine grind through 500‐μm mesh size had the highest total dietary fibre, WHC (12.5 g g⁻¹), SC (12.7 mL g⁻¹) and OHC (2.7 g g⁻¹). Decreasing particle size will trigger a redistribution of some fibre composition from the insoluble to the soluble fraction. The WHC and SC of the sieved DFs decreased with reducing mesh size (500–40 µm). The OHC of DF with Flavourzyme treatment reduced with decreasing mesh size (500–100 µm), but improved with mesh size less than 100 µm.