Optimization of Single Screw Extrusion Processing Variables of Brewing Spent Grain, Soy Flour, Rice Flour and Cranberry Pomace Blend Extrudates on the Physical and Sensory Properties of an Extrudates

Abstract

The main purpose of this study was to optimize the extrusion temperature and screw speed to develop extruded cereals by adding soy flour, rice flour, and brewing spent grain. In the first phase the extruded product was made by optimization and in the second phase cranberry pomace was used based on optimized condition to carry out the sensory properties and textural profile analysis of the extrudates. The extrusion was done in a single screw extruder by adding 25% of water. The physiochemical properties of the extrudate were determine. A central composite rotatable design (CCRD) was used to determine the operating conditions of the extruder. The response surface methodology (RSM) was applied using a CCRD to determine the regression model, ANOVA, numerical optimization, 3-Dimensional models, and graphical optimization. In the first phase, the increase in extrusion temperature and screw speed decreases the expansion ratio, crispness, porosity, rehydration ratio and total color difference but increases the hardness, piece density, water solubility index and L-value. The ANOVA result of all the physiochemical properties shows that there is significance difference (p < .05) among the samples. The overall finding of this study showed that the optimum condition found was at 135°C extrusion temperature and 305 rpm screw speed to make an extruded snack. The sensory result showed that no cranberry pomace (0%) added product became favorite among all three samples, but hardness increases by increase in cranberry pomace content.