The Influence of Barrel Temperature and Feed Moisture on Chemical, Physical and Sensory Quality of High Protein Extrudates from Khao Dawk Mali 105 Brown Rice Flour

Abstract

The objective of this study was to evaluate the effect of barrel temperature and feed moisture on the chemical, physical and sensory quality of high protein extrudates. A 2x3 factorial in CRD with two levels of barrel temperature (140 and 160 ºC) and three levels of feed moisture (16, 18 and 20 %) were used in this study with 350 rpm of screw speed. Results showed that at 160°C of barrel temperature caused a decrease in bulk density and hardness of extrudates, but slightly increase in expansion ratio, total phenolic content and antioxidant activity (Diphenyl-picryhydrazyl radical scavenging assay, DPPH and Ferric ion reducing antioxidant power assay, FRAP) of extrudates compared to that of 140°C barrel temperature. The bulk density and hardness of extrudates increased whereas expansion ratio, total phenolic content and antioxidant activity (DPPH and FRAP) of extrudates decreased with increasing of feed moisture. However, the level of feed moisture and barrel temperature in this study had no significant effect on protein content. The extrudates exhibited high protein content in the range of 11.51 – 11.57%. The result of sensory evaluation by using 9-point hedonic scale showed that the highest liking scores of all sensory attributes were obtained from 160ºC of barrel temperature and 18% of feed moisture treatment. At this condition the mean overall liking scores of high protein extrudates was 8.04 (like very much).