Air classification of bean flour—effects on protein, antinutritional factors and the effect of a fines fraction on cultured explants of small intestinal mucosa

Abstract

Abstract Common beans (Phaseolus vulgaris L, cv Processor) were ground in different mills followed by air classification at two different classifier settings. These procedures yielded fines fractions containing protein levels ranging from 40.0% to 52.6%, depending mainly on cut points with classification. In the fines fractions, the protein content was at least double the level of the initial flour. Furthermore, levels of trypsin inhibitor activity and total and functional lectins in the fines fractions were one‐ to fourfold those of the initial flour. The coarse fractions, however, were not free of these antinutritional factors. Villus length in cultured explants of small intestinal mucosa was decreased in the presence of an air‐classified fines fraction. In addition, epithelium microvesicles were formed. From the present experiment it is concluded that air classification is effective in producing protein concentrates from Phaseolus beans. A clear separaton of constituents with lectin or trpsin inhibitory activity is not established. Based on the pathological effects of its constituents, fines fractions cannot be used in feeding practice without prior elimination of the lectins.