EFFECTS OF TEMPERATURE AND PROTEIN-CONTENT ON PHYSICAL-PROPERTIES OF PASTA MADE FROM RICE ENRICHED WITH SOYBEAN BY EXTRUSION-COOKING .1. EFFECT ON WATER-ABSORPTION AND SOLUBILITY EMPLOYING RESPONSE-SURFACE ANALYSIS

Rice flour was mixed with various amounts of defatted soybean flour in order to obtain a mixture with protein levels of 15, 20 and 25%. Thes e mixtures were processed in a one-screw Brabender 20 DN extruder at t emperatures of 80, 100 and 120 degrees C. Below 20% of protein concent ration, the water absorption index (WAI) increased, with increasing ex trusion temperature, and below 90 degrees C the WAI increased with inc reasing protein concentration. The water solubility index (WSI) notibl y increased with increases in bath temperature and protein concentrati on.