Effect of Die Configuration on the Physico-Chemical Properties, Anti-Nutritional Compounds, and Sensory Features of Legume-Based Extruded Snacks

Abstract

Legumes are not valued by all consumers, mostly due to the prolonged soaking and cooking process they require. This problem could be solved by preparing legume-based ready-to-eat snacks. In this study, the effect of two different dies (circular and star-shaped, with cross-sections of 19.6 and 35.9 mm2, respectively) on the physico-chemical properties, anti-nutritional compounds, and sensory features of extruded breakfast snacks was determined. Extruded products were obtained from 100% legume flours of red lentil, faba bean, brown pea, and common bean. The extrusion-cooking conditions were 2.5 g/s feed rate; 160 ± 1 °C die temperature; 16 ± 1 g/100 g feed moisture, and 230 rpm screw speed. Star-shaped extrudates showed a lower expansion ratio, degree of starch gelatinization, and water solubility index, as well as higher bulk density, hardness, crunchiness, and lightness (L*) values. The oligosaccharides showed non univocal variations by changing the die, whereas phytates did not vary at all. The extrudates from lentil flour (richer in fiber) were the least preferred by sensory panelists, due to their hard texture. However, the spherical extrudates were preferred over the star-shaped product. These results emphasize the possibility of improving the physico-chemical and sensory properties of legume extrudates by selecting a proper die.