Whole faba bean flour exhibits unique expansion characteristics relative to the whole flours of lima, pinto, and red kidney beans during extrusion.

Abstract

Determining the impacts of extrusion conditions on extrudate characteristics of whole beans flours is critical to find the suitable types of beans to use for making direct expanded products. Whole bean flours of four different bean types, faba, lima, pinto, and red kidney, were extruded. The influence of barrel temperature (120, 140, and 160°C), moisture content (17%, 21%, and 25%), and screw speed (150, 200, and 250rpm) on process and product responses was studied with a corotating twin screw extruder. The barrel temperature, moisture content, screw speed, and variety of bean had significant influence on process and product responses, back pressure (MPa), torque (N·m), specific mechanical energy (kJ/kg), expansion ratio, water absorption index (g/g), and water solubility index (%) (P<0.05). Faba bean extrudates had a significantly higher expansion ratio compared to other beans (lima, pinto, and red kidney beans) even though faba bean contained significantly higher protein and higher crude fiber contents (P <0.05). PRACTICAL APPLICATION: The outputs of this research will be helpful to the food industry in the production of high nutrient-dense food products from whole beans by maintaining the expansion and texture of the products. The data should assist to choose the suitable types of whole bean flours and the optimum processing conditions for making direct expanded extruded products.