Effect of extrusion variables on antioxidant activity, total phenolic content and dietary fibre content of gluten-free extrudate from germinated Chenopodium (Chenopodium album) flour

A Box-Behnken design was used to study the effects of feed moisture content (18-20%), barrel temperature (115-135 degrees C) and screw speed (225-275 rpm) on the responses; antioxidant activity, total phenolics, dietary fibre, colour (L-value), hardness, expansion ratio, water absorption index and overall acceptability for development of gluten-free extrudate based on germinated Chenopodium album flour. Second-order polynomial fitted model showed that temperature most significantly (P <= 0.05) affected the antioxidant activity (AoxA), total phenolics (TPC), expansion ratio, hardness and overall acceptability (OA). Antioxidant activity, total phenolic content and dietary fibre of extrudate varied from 11.56 to 15.93%, 56.77 to 81.28 mg/100 g and 18.65 to 22.06 g/100 g, whereas the lightness and hardness of extrudates ranged from 64.02 to 68.35 and 12.26 to 19.49 N, respectively. The results of this study validate the production of functional and acceptable snack product made from C. album flour by extrusion cooking.