Effect of extrusion process on germinated lentil (Lens culinaris) based snack foods: Impact on starch digestibility, physio-functional, and antioxidant properties

Abstract

Lentils (Lens culinaris) are among the oldest crops, consumed by humans since ancient civilization, and are known for their affordability in terms of protein, carbohydrates, and other vital micro-nutrients. The presence of bioactive compounds made them highly nutritive, however, they also contain antinutrients. In the present study germinated green and red lentil flour were extruded with corn flour. Response surface methodology was employed to study the effect of moisture, percent blend of lentils, and screw speed at 150 ̊C barrel temperature on expansion ratio, extrudate density, hardness, water absorption index, water-soluble index, total phenolics content, total antioxidant activity, and in-vitro starch digestibility. The percentage of germinated lentil flour in the blend demonstrated more significant effects on the response variables as compared to moisture and screw speed. Optimum process parameters were observed at 20 % blend, 19.53 % moisture and 147.26 rpm screw speed for germinated green lentil extrudates and 20.72 % blend of germinated red lentil flour, 19.67 % moisture and 140.94 rpm screw speed for germinated red lentil extrudates. The germination technique followed by microwave-vacuum drying (MVD) and extrusion can enhance the nutritive value and utilization of lentils in new product development.