ABSTRACT

The effect of soaking, roasting, boiling and autociaving on some of the antinutritional factors (trypsin inhibitor, haemagglutinin and oligosaccharides) in the seeds of African yam bean were investigated. From the data obtained, the percent reduction of these antinutritional factors were determined with reference to the antinutritional levels of the raw African yam bean sample. The result showed that samples soaked for 6 hrs gave the least percent reduction in the antinutritional factors studied, of 16%, 0.8% and 0% for trypsin inhibitor, haemagglutinin and oligosaccharides content respectively while for 30 hrs soaking, there was better reduction of 54% trypsin inhibitor, 46% haemagglutinin and 17% oligosaccharides. Roasting for 30 mm. gave reduction of 65% trypsin inhibitor, 19% haemagglutinin and 16% oligosaccharides compared to when roasted for 60 and 90 mm., while roasting for at least 120 mm. gave greater reduction of 100% trypsin inhibitor and lesser amount of 35% haemagglutinin and 16% oligosaccharides. Boiling for 60 mm. markedly reduced the whole antinutritional factors to 67% trypsin inhibitor, 100% haemaggiutinin and 75% oligosascharides. Sample autoclaved for 5 mm. gave lesser amount of the antinutritional factors while autoclaving for 30 and 40 mm. progressively reduced trypsin inhibitor at 83% and 100% respectively with haemagglutinin and oligosaccharides being reduced to 35% and 75% respectively. Of all the processing mellods studied based on their different time, boiHg for 60 mm. gave the best method for eliminating the content of trypsin inhibitor, haemagglutinin and oligosaccharides.