Abstract

Rice flour was added in different proportions (10 - 30%) to dehydrated carrot pomace and pulse powder (CPPP) mixture having equal ratio. The formulation was extruded at different moisture content (17 - 21%), screw speed (270 - 310 rpm) and die temperature (110 - 130°C). The lateral expansion, bulk density, water absorption index, water solubility index, hardness and sensory characteristics were measured as responses. Significant regression models were established with the coefficient of determination, R² greater than 0.72. The results indicated that CPPP proportion and moisture content significantly influenced (P < 0.10) lateral expansion; temperature for water absorption index; screw speed and temperature for hardness and screw speed for sensory score. The compromised optimum condition obtained by numerical integration for development of extrudates were: CPPP mixture of 16.5% in rice flour, moisture content 19.23%, screw speed 310 rpm and die temperature 110°C. Sensory evaluation revealed that carrot pomace could be incorporated into ready-to-eat expanded products upto the level of 8.25%.

Key words: Twin screw extrusion, carrot pomace, response surface methodology, rice flour, pulse powder.