Amylograph properties and microstructure of white corn and okara-based composite flour

Abstract

Okara flour is rich in protein and dietary fiber and could be used to enrich white corn flour to enhance its functionality. This research was designed to investigate the amylograph properties and microstructure of a composite flour made from white corn and okara flours. The composite flour was made using five different ratios of white corn flour:okara flour (100%:0%, 95%:5%, 90%:10%, 85%:15%, and 80%:20%). White corn flour and okara flour were mixed manually and prepared in duplicates. Amylograph properties were observed using a Rapid Visco Analyzer (RVA) and microstructure was observed using Scanning Electron Microscopy (SEM). The composite flour had a pasting temperature range of 78.30°C to 79.90°C, peak viscosity of 126cP to 1977cP, trough viscosity of 1016cP to 1596cP, breakdown viscosity of 245cP to 516cP, final viscosity of 2079cP to 3248cP, and a setback viscosity range of 1063cP to 1652cP. Microstructural analysis clearly showed that white corn and okara flour particles did not break. Composite flours based on the white corn and okara mix used in this research could potentially be developed as raw materials for use in food products with characteristics that are not brittle nor easily broken, including analog rice.