Instrumental and Sensory Evaluation of Textural Properties of Extrudates from Blends of High Starch/High Protein Fractions of Dry Beans

A Wenger X5 single-screw extruder was used to produce bean extrudates from formulations modified by addition of high protein bean fraction or hull. The effect of process temperature was investigated. The higher the process temperature, the lower was the sample stress and the higher the sensory score for crispness. Product processed below 121°C was unacceptable. Crispness was good for samples containing 13–16% protein or 17–21% fiber; outside these ranges the extrudates were too hard. Shear stress increased uniformly with increasing protein or fiber content. A satisfactory correlation was observed between sensory and instrumental test results for texture: the higher the shearing stress, the lower was the sensory score for crispness.