Nutritional evaluation of kidney beans (phaseolus vulgaris): The toxic principle

Abstract

Kidney bean (Phaseolus vulgaris) lectins were purified by affinity chromatography on a fetuin‐Sepharose‐4B column. The net protein utilisation (NPU) of rats fed on a 5% casein‐containing diet was strongly depressed by these pure lectin preparations. The extent of this nutritional toxicity was found to be related to the lectin content of the diet according to the following equation: NPU = NPU_{5% casein} −280 x (where x is the lectin content in % w/w). Thus, because in addition lectin‐free kidney bean protein preparations were found to be non‐toxic for rats, it is now suggested that the toxic principle of kidney bean is identical with its constituent lectins.