Heat-Labile Growth-Inhibiting Factors in Beans (Phaseolus vulgaris)

Otras publicaciones, Werner Jaffe

Heat-Labile Growth-Inhibiting Factors in Beans (Phaseolus vulgaris)

WERNER G. JAFFÉ AND CLARA L. VEGA LETTE

Instituto Nacional de Nutrición, Caracas, Venezuela, Apartado 2049

A comparative study in vitro was made of enzyme-inhibiting and hemagg1utinin activities, and the effect on rat growth of 5 varieties of kidney beans (Phaseolus vulgaris). Extracts of 2 bean samp1es were active in agg1utinatingrabbit b1ood cells and toxic when.fed to growing rats. Diets prepared with these seeds supp1emented with methionine caused weight 10ss and death when fed to rats a10ne or with a supp1ement of 10% enzymatically or acid-digested casein. Hemagg1utinating activity was observed in the feces of rats fed the raw bean diets. The possibility that the hemagg1utinins are at 1east partly responsible for the toxic effects was examined. Three other samples of kidney beans had no significant hemagglutinating or 1ethal effect. Rats fed the raw seed meals supp1emented with methionine did not gain weight but grew well with a similar diet supp1emented with enzymatically digested casein. Supplements of 10% casein, 1% Na glutamate, or 10% acid-digested casein did not improve growth significantly but the latter did when tryptophan was added. Antitrypsin and antiamylase activities were low or absent in some of the seeds and high in others, and did not appear to be directly re1ated to the growth inhibition observed. The low growth-promoting action of the hemagglutinin-free beans might be explained by 10w digestibility and an enzyme-inhibiting activity of the bulk proteins different from that of the trypsin or amylase inhibitors.

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