Dehydrated carrot pomace was added in different proportions (10-30%) to rice flour. The formulation was extruded at different moisture content (17-21%), screw speed (270-310 rpm) and die temperature (110-130°C). The experimental combinations were decided based on central composite rotatable design for four variables at five levels of each variable. 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 0.70. The results indicated that pomace proportion, screw speed and temperature significantly influenced (P<0.10) lateral expansion; moisture content and screw speed for bulk density; pomace proportion and temperature for water absorption index and water solubility index, pomace proportion, 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: carrot pomace of 11.75% in rice flour, moisture content 19.92%, screw speed 249.1 rpm and die temperature 114.3°C. Sensory evaluation revealed that carrot pomace could be incorporated into ready-to-eat expanded products upto the level of 11.75%.
- carrot pomace,
- response surface methodology,
- rice flour
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