Co‐extrusion of pearl millet‐whey protein concentrate for expanded snacks

A study was conducted to develop pearl millet‐based extruded snacks with whey protein concentrate (WPC) to enhance its acceptability and nutritional value. Pearl millet grits (841 μ) was extruded with different levels (0%, 2.5%, 5.0% and 7.5%) of WPC at constant feed rate (10.5 kg h^?1) and moisture content (14%). Addition of whey protein at 7.5% level significantly (P ≤ 0.05) increased T_g from 75.1 ± 0.26 °C to 120.5 ± 1.28 °C and T_m from 89.1 ± 1.51 °C to 158.7 ± 1.37 °C, which resulted in less expanded and harder extrudates. The expansion index of extrudates was negatively correlated (P ≤ 0.05) with protein (r = ?0.940), bulk density (r = ?0.949), hardness (r = ?0.971) and breaking strength (r = ?0.921), while positively correlated (P ≤ 0.05) with overall acceptability (OAA; r = 0.988). Keeping in view the nutritional, textural and consumer's acceptability, incorporation of 5% WPC in pearl millet grits (841 μ) was recommended for preparation of acceptable expanded snacks.