Effect of twin‐screw extrusion on gelatinization characteristics of oat powder

Abstract

AbstractThe effect of extrusion treatments on oat gelatinization, microstructure, and macroproperties were important during twin‐screw extrusion. In this work, single factor and orthogonal experiments were conducted to evaluate gelatinization degree, expansion ratio, water solubility index, and water absorption index of oat powder before and after extrusion. Results indicated that the optimum gelatinization degree was 96.92% under the conditions of 18% moisture content, 155°C barrel temperature, and 150 rpm screw rotating speed. According to appearance by scanning electron micrograph, the extruded oat changed from the original tightly wrapped texture to spongy and porous form with lower gelatinization temperature (88.00°C) than those without extrusion (91.35°C). Rapid viscosity analysis showed that extruded oat became more stable and easier to gelatinization, which was consistent to the in vitro digestion experiment, suggesting extruded oat could be applied as ready‐to‐eat food in the further application.Practical applicationsThe purpose of this research was aimed to optimize the extrusion and ripening process of oat powder, to explore the effect of curing method on the characteristics of oat powder, and to compare the physical and chemical properties of oat powder before and after extrusion. Eventually, the optimized process of oat powder using twin‐screw extrusion technology improved the structural characteristics of oat powder and enhanced the digestibility of the product.