Effect of Processing on Anti-nutritional Factors and Sensory Qualities of ‘Hepho’, a Black Climbing Bean (Lablab purpureus L.) Flour

Abstract

Food quality of most legumes depends upon the processing methods applied and presence or absence of anti-nutritional or toxic factors.  It is widely accepted that simple and inexpensive processing techniques are effective methods of achieving desirable qualities of processed legume seeds. The aim of this study was to evaluate the effect of processing on anti-nutritional factors (tannin and Phytate) and sensory characteristics (taste, bitterness, appearance, texture and overall acceptability) of hepho (Lablab purpureus L) flour. Hepho is the Afan Oromo name for black climbing bean which is an indigenous legume in Ethiopia. The processing techniques employed were traditional cooking (TC) and pressure cooking (PC) of the dehulled and undehulled hepho bean while the raw sample was served as a control. All the processing methods significantly reduced (P<0.05) the anti-nutritional factors under investigation. Of the two processing techniques, the reduction of the antinutritional factors by PC was evaluated to be higher than that of TC. The sensory analysis showed that there is no significant difference (P > 0.05) between dehulled TC and dehulled PC as well as undehulled TC and undehulled PC. But there is a significant difference (P<0.05) between dehulled and undehulled TC and PC methods. The overall acceptability rating was higher for dehulled seeds in both the treatments. From this it can be concluded that simple processing techniques can drastically reduce some anti-nutritional factors thereby increase the biological value of legumes and the same processing techniques can result in increase of the overall acceptability of dishes produced from legumes.

Keywords: Hepho (Lablab purpureus L.), processing methods, ant-nutritional factors, sensory characteristics.