A novel method for quantitation of favism-inducing agents in legumes.

A new method for the quantitation of the favism-inducing agents in legumes is described. The procedure involves differential extraction of the glucosides vicine and convicine with acetic acid (25%), followed by an enzymatic hydrolysis by beta-glucosidase under anaerobic conditions. Each of the aglycone moieties, isouramil and divicine, anaerobically reduces two molecules of o-ferriphenanthroline to o-ferrophenanthroline. This reaction is readily followed spectrophotometrically at 515 nm. Using this procedure, it was found that in various strains of Vicia faba, the level of these two glucosides comprises approximately 0.5% of the wet weight of the seeds. In contrast, these glucosides could not be detected in either green peas or chick peas.