Effect of Single Screw Extrusion Parameters on Textural Properties of Rice based Expanded Snacks Enriched with Okara

Abstract

Objective: The objective of present research work is to investigate the effect of single screw extrusion parameters on textural properties of rice based expanded snacks enriched with okara. Method/Analysis: The expanded snacks were prepared through extrusion cooking of broken rice (Oriza Sataiva L) with Okara (a by-product of soy milk)by using a Brabender single-screw extruder. The effects of machine parameters (i.e. barrel temperature (120-160°C), die head temperature (160-200°C), screw speed (50-90 rpm)) and feed parameters (i.e. blend ratio of broken rice and okara (70:30-90:10) and moisture content of feed (14-22 percent w.b.) were analyzed using Response Surface Methodology (RSM) with central composite rotatable design. Multiple regression equations and various response surface plots were generated to show the impact of each independent parameter on the quality of extruded snacks. Findings: The extruded snacks textural characteristics (hardness and crispness) were determined by texture analyser. The product textural characteristics were found to be most dependent on feed moisture content, blend ratio, barrel temperature and die head temperature. The presence of okara in blend ratio contributed to decrease the crispness and to increase in hardness of extrudate. Applications: This research effort to encourage the utilization of by-products of rice mill and soy milk units for the production of new value added expanded snacks. Textural properties (Hardness, Crispness etc.) of expanded snacks have prime importance in the acceptability of extruded product among the consumers.