Characterization of Extrudate Prepared from Rice (Oryza sativa L) and Chapra (Fenneropenaeus indicus) by Twin Screw Extrusion

Abstract

Rice (Oryza sativa L) and chapra (Fenneropenaeus indicus) mixture was extruded using a co-rotating fully intermeshing twin-screw extruder. The extrudates were analyzed for protein solubility, Water Absorption Index (WAI), Water Solubility Index (WSI) and fragmentation during twin-screw extrusion. Protein solubility significantly decreased with increase in process temperature. Phosphate buffer with added urea was found to extract more protein than plain buffer solution. SDS polyacrylamide gel electrophoresis indicated no fragmentation in protein part. Response surface methodology was used to determine the effect of barrel temperature (120-165oC) and feed moisture content (10-20%) on the WAI and WSI of the extrudate. WAI decreased with increase in temperature from 120-135oC and increased with further increase in temperature from 135-165oC. Similarly, decrease in WSI values with increase in temperature and moisture was observed.