Effect of soaking followed by cooking and the addition of α-galactosidase on oligosaccharides levels in different Canavalia accessions

The seed materials of different accessions of Canavalia ensiformis and Canavalia gladiata were collected from the Eastern and Western Ghats, South India and they were subjected to analysis for their oligosaccharide content. Further, the effect of soaking followed by cooking, a traditional processing method, and partially purified α-galactosidase, extracted from a common guar weed (Cassia sericea), on the levels of flatulence factors (raffinose, stachyose and verbascose) in different accessions was investigated. The contents of raffinose, stachyose and verbascose and total oligosaccharides in all the investigated accessions of raw seed samples ranged between 0.68 and 1.47; 0.61 and 2.61; 3.47 and 6.64 and 4.92 and 9.84 g 100 g−1 seed flour, respectively, and verbascose being the predominant oligosachharide. Application of partially purified α-galactosidase significantly reduced the content of oligosaccharides (71–85%) rather than soaking followed by cooking (14–47%). Such enzymatic treatment could enhance the utilization of Canavalia beans as a potential food source without flatulence obstacles compared to conventional treatments.