Shear-induced enhancement of technofunctional properties of whole grain flours through extrusion

Abstract

Thermo extrusion is a practical and achievable approach to produce flours with improved techno-functional properties. The aim of this study was to compare the potential of different whole cereals, pseudocereals and legumes to produce techno-functional flours by means of high-shear extrusion. Whole flours from oat, sorghum, amaranth, quinoa, chickpea, lentil, black bean and pinto bean were extruded under selected specific mechanical energy (SME) to achieve functional modifications. Refined rice flour was used for comparison purposes. Extruded flours presented a diversity of functional properties depending on the raw material. In general, hot peak viscosity was lost and final viscosity was significantly reduced due to the extrusion conditions. Extruded flours presented higher apparent viscosities under cold conditions compared to raw flours. The hydration properties and water solubility index were improved after extrusion. The oil binding capacity, protein solubility and foaming properties were affected depending on the extruded material. Extruded flours produced with cereals and legumes presented cold-gelling capacity. The texture of gels differed depending on the raw material and resting temperature and time. Extruded whole grain flours presented comparable or even better techno-functional properties compared to the extruded refined rice flour. Results obtained herein are promising and may be used to tailor made new techno-functional ingredients that can be used for formulation of new food products.