Hydrolysis of oligosaccharides in soybean products by Debaryomyces hansenii UFV-1 α-galactosidases

α-Galactosides are abundant sugars found in legumes such as soybean. Since humans and monogastric animals lack α-galactosidase in the digestive tract, they are unable to digest these sugars, which induce flatulence. The use of α-galactosidases is promising as a means to overcome this problem, and to increase the consumption of soy products. Immobilized α-galactosidase, derived from Debaryomyces hansenii UFV-1, exhibited an activity of 40 U per g of silica and an activity yield of 50%. The optimum pH of free and immobilized α-galactosidase was 5.0 and the optima temperatures were 60 and 80 °C, respectively. The soymilk stachyose was completely hydrolyzed by different enzyme forms after incubation for 4 h at 60 °C, while raffinose was reduced by 100%, 25% and 68% by free, immobilized enzymes and permeabilized cells, respectively. The soy molasses treatment with free enzyme for 6 h promoted reduction in stachyose and raffinose contents by 100% and 50%, respectively.