Chemical, Functional, Rheological and Structural Properties of Broken Rice–barnyard Millet–green Gram Grits Blend for the Production of Extrudates

Abstract

Broken rice is an underutilized by-product of the rice milling industry. It was added with green gram and barnyard millet to investigate as a source of nutrition-based value-added food product. The study was carried out to examine the influence of formulated composite flour obtained from broken rice (Oryza sativa) (50%–80%), barnyard millet (Echinochloa esculenta) (10%–30%), and green gram (Vigna radiata) (10%– 30%) on the chemical properties, functional properties, pasting properties, oscillatory test, flour behavior, and microstructure of extrudate. The ash, crude fiber, crude protein, fat, and carbohydrate of the extrudate ranged from 1.62%–1.78%, 1.88%– 2.43%, 13.47%–14.57%, 4.9%–7.48%, and 66.86%–70.8%, respectively. The water absorption index (WAI) and water solubility index (WSI) for the flour ranged from 5.06%–6.18 g/g and 2.34%–3.99%. The formulated composite flours having a higher percentage of broken rice showed significant differences (p < 0.05) in their pasting properties, pasting temperature, peak viscosity, breakdown viscosity, and setback and final viscosity. The pasting properties gave better results using a twin-screw extruder with operating conditions of barrel temperature of 110 C, screw speed of 290 rpm, and 14% moisture content (w.b.). The microstructure of the extrudate obtained from 80% broken rice, 10% barnyard millet, and 10% green gram grits flour possessed a more integrated, well-defined porosity, indicating a completely gelatinized structure.