Physical, chemical, and techno-functional properties of soy okara powders obtained by high pressure homogenization and alkaline-acid recovery

Abstract

High pressure homogenization (HPH) at increasing intensity (50, 100, 150 MPa and 150 MPa for 5 passes) was combined with an alkaline-acid recovery method to prepare protein-enriched okara powders intended as ingredients with improved techno-functional properties. The treatment allowed obtaining from 4 to 8 g powder per 100 g fresh okara. The intensity of HPH treatment significantly affected amount, composition, particle size, protein structure and techno-functional properties. Treatments at intermediate pressures in the range 50−100 MPa resulted the most feasible from an industrial perspective allowing to obtain a good balance between protein content and the techno-functionalities (e.g. solubility, foaming, gelling and emulsifying properties) of the okara ingredient. Thus, HPH combined with simple pH-driven precipitation can be considered an efficacious and industrially feasible pre-treatment for okara valorisation into innovative ingredients.