Optimization of Machine and Process Parameters for Development of Protein and Antioxidant Rich Composite Food using Twin Screw Extruder

Background: Nutritional quality of extruded products can be enhanced through protein, minerals and antioxidants rich foods viz. legumes, green leafy vegetables, dietary fibres, by-products, etc, leading to improvement in functional properties of products and health of consumers. Methods: Extrudates were prepared from maize, defatted soy meal, sesame and spinach using a co-rotating twin screw extruder and dried in a tray dryer at 50oC up to about 5.5% moisture content (w.b.) and analyzed for important product quality parameters. Result: Quality characteristics of developed food grains-spinach based composite food were affected by variability in independent studied parameters. Optimized extrusion conditions for desired composite food from food grains-spinach were as 14% moisture content, 117oC DHT and 335rpm screw speed. These conditions resulted in the products with 18.26% protein, 73.88% in vitro protein digestibility, 2.46 protein efficiency ratio, 2.84% total minerals, 4.67mg/100g iron, 190 mg/100g calcium, 24.05% antioxidant activity with consumer acceptability ≥7 by 92.52%.