Effect of Cooking on Firmness, Trypsin Inhibitors, Lectins and Cystine/Cysteine content of Navy and Red Kidney Beans (Phaseolus vulgaris)

Abstract

ABSTRACT The effect of cooking on firmness, trypsin inhibitor (TI) and lectin activities, and cystine/cysteine (Cys) of navy and red kidney beans was investigated. Beans were soaked and cooked in an open‐kettle at various temperatures and periods. Navy beans canned by two methods were used for comparisons with the open‐kettle cooked beans. The TI activity, lectin activity and Cys content decreased with increasing temperature and/or period. Under some of the cooking conditions, less than 5.5% and 0.1% of TI and lectin activities, respectively, were retained, though the firmness of beans was palatable. Canned navy beans did not have lectin activity but had less than 5% residual TI activity.