Co-extrusion of Dietary Fiber and Milk Proteins in Expanded Corn Products

To improve the nutrient-density of snack products, milk proteins (casein, whey protein concentrate or whey protein isolate) and wheat fiber were co-extruded with corn meal flour, in a twin screw extruder under high shear and high temperature processing conditions. Co-extruding corn products and fiber resulted in the reduction of specific mechanical energy while increasing the expansion and breaking strength of the extrudate. Fiber added at 125 g/kg increased expansion and breaking strength. Whey products alone, at a concentration of 250 g/kg reduced expansion and water absorption properties, but the incorporation of fiber reversed this effect and improved expansion. The negative textural indicators associated with the inclusion of whey products can be improved significantly by adding wheat bran fiber at 125 g/kg. Adding fiber, improved specific mechanical energy (SME) along with product quality characteristics.