Effects of extrusion and traditional processing methods on antinutrients and in vitro digestibility of protein and starch in faba and kidney beans

Comparative effects of extrusion cooking and conventional processing method s on protein content and reduction of antinutritional factor (phytic acid, condensed tannins, polyphenols, trypsin, chymotrypsin, cc-amylase inhibitor s and haemagglutinating activity) levels in Vicia faba and Phaseolus vulgar is seeds were studied. In vitro protein and starch digestibilities were ass essed. P. vulgaris seeds showed highest levels of condensed tannins, chymot rypsin and cc-amylase inhibitory activities and haemagglutinating activity. Dehulling significantly increased protein content and greatly reduced cond ensed tannin and polyphenol levels in both legumes. Extrusion was the best method to abolish trypsin, chymotrypsin, cc-amylase inhibitors and haemaggl utinating activity without modifying protein content. Furthermore, this the rmal treatment was most effective in improving protein and starch digestibi lities when compared with dehulling, soaking and germination. (C) 1999 Publ ished by Elsevier Science Ltd. All rights reserved.