Processing of Soybean Products by Semipurified Plant and Microbial alpha-Galactosidases

摘要

Galactooligosaccharides(GO)are responsible for intestinal disturbances following ingestion of legume-derived products.Enzymatic reduction of GO level in these products is highly desirable to improve their acceptance.For this purpose,plant and microbial semipurified alphalpha-galactosidases were used for GO hydrolysis in soybean flour and soy molasses.alpha-Galactosidases from soybean germinating seeds,Aspergillus terreus,and Penicillium griseoroseum presented maximal activities at pH 4.0-5.0 and 45-65 deg C.The K_(M,app)values determined for raffinose by the soybean,A.terreus,and P.griseoroseum alphalpha-galactosidases were 3.44,19.39,and 20.67 mM,respectively.The enzymes were completely inhibited by Ag~+ and Hg~(~(2+)),whereas only soybean enzyme was inhibited by galactose.A.terreus alpha-galactosidase was more thermostable than the enzymes from the other two sources.This enzyme maintained about 100% of its original activity after 3 h at 60 deg C.The microbial alphalpha-galactosidases were more efficient for reducing GO in soybean flour and soy molasses than soybean enzyme.