Use of Extrusion Technology To Overcome Undesirable Properties of Hard-To-Cook Dry Beans (Phaseolus vulgaris L.)

Abstract

The objective of this work was to study the effects of extrusion cooking on improving the functional and nutritive properties of dry beans that had been stored at 23 ± 3 °C and 65 ± 5% relative humidity for 12 months. After storage, the bean cooking time increased 4.5-fold, while texture and flavor deteriorated in quality. Water absorption, water solubility, and emulsifying capacity were the same for the extrusion cooked beans, before and after storage. Paste viscosity was slightly higher for the beans extruded shortly after harvest. Protein nutritive value of the freshly harvested beans was totally preserved in the stored beans submitted to extrusion cooking. Extruded mixed flours (1 :3 w/w) of freshly harvested beans and rice or stored beans and rice, respectively, improved significantly in their water absorption capacity, viscosity of paste at 25, 90, and 50 °C, and nutritive value, but decreased in water solubility index and in emulsifying capacity, in relation to extruded flours of beans alone.