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For the removal of raffinose and stachyose related to flatulence in soybean, α-galactosidase activity of six commercial enzyme preparations was compared and their enzymatic characteristics were investigated. Among the tested enzymes, one product from Aspergillus niger was shown to be the most potent in α-galactosidase activity. The enzyme characteristics of the selected preparation were shown to be pH 4.0-4.5 for optimum activity, pH 4-5 for optimum stability and 45℃ for optimum activity. Upon reaction on a synthetic substrate, p-nitrophenyl-α-D-galactoside, Michaelis constant was 2.08 mM and maximum velocity was 435 micromoles of substrate/minute/g enzyme preparation. The enzyme was proved to be essential for SH group for its activity and capable of hydrolyzing raffinose, sucrose and p-nitrophenyl-α-D-galactoside almost completely. Thin-layer chromatographic analysis exhibited that the enzyme treatments of raffinose and stachyose were resulted to produce only monosaccharides in 2 hours of hydrolysis. It was, therefore, assumed that the flatulence factor in soybean foods can be easily removed by the use of enzymes showing α-galactosidase activity.
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