Extruded Snacks from Rice, Green lentil, Chickpea and Tomato Powder Finished with Frying / Microwave Roasting

Abstract

Extrudates were first prepared through extrusion-cooking and air-drying of different formulations obtained through a D-optimal Mixture Design containing blends of rice flour (RF), green lentil flour (GL), chickpeas flour (CP), and tomato powder (TP) in different proportions. These extrudates were subjected to deep oil frying (DOF) at 200⁰C or microwave roasting (MWR) at 75% power level (1000W oven) in order to develop desirable color and flavor characteristics. Physical properties including color (L*, a*, b*), expansion ratio (ER), breaking stress (BS) and antioxidant activity (AA) were evaluated, and the influence of product variables on output parameters was assessed. Increasing CP and GL in the formulations resulted in a decrease in the ER and an increase in the BS. However, the inclusion of CP and TP helped to produce snacks of golden yellow color and increased their overall acceptability. The addition of TP also improved the antioxidant activity of the resulting product. Both DOF and MWR resulted in a lower antioxidant activity; however, MWR led to more than 80% retention of the original antioxidants and higher sensory acceptability. ER and L* values had a strong positive correlation with the overall acceptability of products. The extrusion - air-drying - microwave roasting process produced healthy snacks with acceptable sensory quality, high protein (through added pulses), and enriched antioxidant (through added tomato powder) contents.