Effect of soaking, cooking and crude α‐galactosidase treatment on the oligosaccharide content of cowpea flours

Abstract: The effects of soaking, cooking and crude α‐galactosidase treatment on the level of stachyose and raffinose present in cowpea flours were investigated. Soaking for 16 h resulted in an average reduction of 26·2% for stachyose and 28·0% for raffinose, while cooking for 50 min resulted in a reduction of 28·6% for stachyose and 44·0% for raffinose. On the other hand, treatment of cowpea flours for 2 h at 50°C with crude fungal preparations having an α‐galactosidase activity equivalent to 64 units μg−1 protein, brought about a mean decrease of 82·3% for stachyose and 93·3% for raffinose. These results show that the enzyme treatment was more effective in removing the raffinose‐family oligosaccharides and hence could be a useful technique for control of the flatulence‐inducing activity of cowpea flours.