Effects of Dehulling and Extrusion‐Cooking on the Nutritional and Physicochemical Properties of Navy Bean ( Phaseolus vulgaris L .) Flours

Abstract

This study evaluated the impact of dehulling on the nutritional, physicochemical, techno-functional, and sensory properties of navy beans (Phaseolus vulgaris L.) before and after twin-screw extrusion. Whole (B) and dehulled (DB) bean flours were characterized for composition, antinutritional factors, functional properties, color, and microstructure. Dehulling increased protein (from 20.1 to 21.3 g/100 g) and starch content (44.9 to 46.4 g/100 g), while reducing dietary fiber (21.2 to 17.9 g/100 g). During extrusion at 150 °C and 14–18% moisture, dehulled samples required lower specific mechanical energy (SMEC; 902–1006 vs. 981–1052 J/g) and showed significantly higher expansion (E = 2.0 vs. 1.5) and specific volume (SV = 3.0 vs. 2.3 cm³/g) than whole-bean extrudates. Solubility increased after extrusion in both materials, reaching 30–31 g/100 g in EDB compared with 27–28 g/100 g in EB. At the optimal moisture level (16%), EDB exhibited higher protein digestibility (66.8% vs. 58.2%) and a 43% reduction in phytic acid (from 1.6 to 0.91 g/100 g), while trypsin inhibitors were fully eliminated in both extrudates. Sensory evaluation indicated that samples extruded at 16% moisture provided the best balance of flavor, creaminess, and ease of preparation. Overall, dehulling combined with extrusion greatly enhanced functional properties, reduced antinutritional factors, and improved protein quality, demonstrating strong potential for the development of nutritious bean-based expanded snacks and instant flours.