Lipoxygenase Activity in Fourteen Legumes

Abstract

Lipoxygenase activities of legumes are difficult to compare due to various assay methods and means of expressing results. The present investigation determined the lipoxygenase activities of fourteen legumes under identical conditions. Lipoxygenase activity was measured by the increase in absorption at 234nm due to the production of the conjugated diene products. Lipoxygenase activity ranged from 1.68×106units/mg extractable protein in mung bean to 2.41×107units/mg extractable protein in lentil. The legumes studied were grouped into three classes based on their lipoxygenase activity per mg flour. Legumes which possessed a high level of activity were soybean, cowpea and lentil; legumes which possessed a medium level of activity were adsuki bean, faba bean, field pea and five biotypes of Phaseolus vulgaris (black bean, great northern bean, navy bean, pinto bean and red kidney bean); legumes which possessed a low level of activity were chickpea, lima bean and mung bean. The high lipoxygenase activity of lentil at pH 6.9 suggests the use of lentil flour as an alternative for soybean flour in the baking industry in Western Canada.