Original article Co-extrusion of pearl millet-whey protein concentrate for expanded snacks

Summary 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 l) 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 Tg from 75.1 � 0.26 °C to 120.5 � 1.28 °C and Tm 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 l) was recommended for preparation of acceptable expanded snacks.