Improvement of Functional and Nutritional Properties of Extruded Snacks with the Utilization of Red Dog Flour

Red dog flour (RDF), a milling by-product, is rich in nutritionally and functionally crucial components. Extrusion conditions for extruded corn snacks (ECS) with RDF were optimized using Response Surface Methodology (RSM) with Box-Behnken Design (moisture content: 13.5%, RDF ratio: 20%, screw speed: 468 rpm, and die temperature: 110?). Then, functional, nutritional, and sensory properties of ECS containing an increasing ratio of RDF were determined. The addition of RDF improved ash (1,84 fold), fat (2,7 fold) protein (0,51 fold), dietary fiber (roughly 2,8 fold), and mineral content (Fe, K Mg, P, and Se) significantly compared to ECS without RDF. Extrusion condition considerably declined the total phenolic content (from 144.50 to 25,09 mg GAE/100g), Trolox equivalent of antioxidant capacity (from 1.13 to 0.41 mMol Trolox/g), and phytic acid content (from 2147 to 968.11 mg/100g) of ECS with RDF compared to raw materials. However, the increasing ratio of RDF had an increment in bioactive compounds (up to 2,38 fold mg GAE/100g, and 1,63 fold mMol Trolox/g) and phytic acid content (up to 0.36 fold). According to the sensory evaluation, 30% of ECS with RDF was the most preferable snack.