Fortification of lentil chips with multiple vitamins and minerals using hot extrusion technology: effects of moisture, extrusion temperature, conditioning, and storage techniques

This study sought to explore the development and fortification of lentil chips using hot extrusion technology (HET) to find out the effect of moisture, extrusion temperature, conditioning time, and storage life. The chips were fortified using four food fortifying agents, viz. FAO recommended vitamin and mineral premixes (T 2 ), carrot powder (T 3 ), pumpkin powder (T 4 ), and a combination of carrot and pumpkin powder (T 5 ) with control (T 1 ). High barrel temperature, increasing viscosity of the dough in the shaft of the gearbox, feed moisture, material ratio, feeding rate, and feeding & conditioning time were the main barriers of single screw extruders for producing high-yield quality chips. Results revealed that incorporation of whole lentils with other ingredients, 1.0 % feed moisture, conditioning 2-3 hrs, feed rate and time 4.12 kg/hr, and extrusion temperature 115 ± 5 °C led to an increase in the yield of chips (4 kg/hr or 8000 pouches/hr) with higher swelling capacity. The study indicates that fortification process increased crude protein, β-carotene, vitamin C, vitamin D and bioactive compounds as compared to control with a range of 23.07 to 26.31 %, 39.43 to 43.81 mg/100 g, 3.21 to 3.53 mg/100 g, 53.48 to 69.34 µg/100 g and 7.14 to 9.95 mg GAE/100 g respectively. The chips fortified with native sources of raw materials (T 3 -T 5 ) contained higher levels of nutritional and bioactive compounds compared to those with multiple vitamins and minerals (T 2 ). Similarly, the loss of vitamin C and β-carotene during processing and fortification had been documented from 19.19 to 20.49 % and 2.08 to 40.34 % respectively. Moreover, native sources of fortification agents, especially combined pumpkin and carrot powder (T 5 ), were found to be promising as an alternative to FAO-recommended multi-vitamin and mineral premixes. The sensory evaluation confirms that the fortified chips accomplished the highest overall acceptability score from 7.13 to 7.25, with better crispiness (7.50-7.57). The marketable life of the chips could be extended up to 4 months at ambient conditions. The benefit-cost ratio (BCR) of the chips for retail and wholesale prices was calculated as 2:1 and 1.6:1. The findings suggest that the processors could simply process the lentil chips as a low-cost technique by fixing the feed moisture, extrusion temperature, and conditioning time with a single screw extruder.