Reduction of soybean oligosaccharides and properties of alpha-D-galactosidase from Lactobacillus curvatus R08 and Leuconostoc mesenteroides [corrected] JK55.
This study was undertaken to investigate the potential for reducing non-digestive oligosaccharides (NDO) in soy foods, as well as the influence of exogenous conditions on intracellular alpha-galactosidase (alpha-Gal) producing lactic acid bacteria. Two strains, Lactobacillus curvatus R08 and Leuconostoc mesenteroides [corrected]JK55, showed the highest levels of raffinose degrading activity at over 40 U mL(-1), and presented maximum activities during the stationary phase in a medium where raffinose was the only carbon source. Raffinose was the most effective inducer, followed by melibiose, and galactose; the enzymes were partially inhibited by fructose and sucrose. On the other hand, limited activity was observed in glucose. The strains displayed optimum activity levels at neutral pH and a 35-37 degrees C temperature range. The alpha-Gal activities of L. curvatus R08 and Leu. mesenteroides [corrected] JK55 were maintained at pH 6.5-10.0. The activity of the alpha-Gal enzyme was stable in a relatively broad range of temperatures from 0 to 40 degrees C for 3h. In soymilk, Leu. mesenteroides [corrected] JK55 and L. curvatus R08 completely hydrolyzed the NDO after 18-24h of fermentation. The abilities of L. curvatus R08 and Leu. mesenteroides [corrected] JK55 to degrade raffinose sugars and, particularly, to produce organic acids from sugar, could contribute to reductions in the anti-nutritional properties of soy, and to the accumulation of compounds with beneficial properties during food processing. Furthermore, this study provides the optimum conditions to induce alpha-Gal from these strains.
Yoon
Mi Young
MY
Graduate of Life Sciences and Biotechnology, Korea University, 5-1, Anam-dong, Seongbuk-Gu, Seoul 136-701, Republic of Korea.
Hwang
Han-Joon
HJ
D005285:Fermentation; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000201:enzymology*; D007934:Leuconostoc / Q000201:enzymology*; D009844:Oligosaccharides / Q000378:metabolism*; D011887:Raffinose / Q000378:metabolism; D041942:Soy Milk / Q000737:chemistry; D013025:Glycine max / Q000737:chemistry*; D013696:Temperature; D000519:alpha-Galactosidase / Q000378:metabolism*
D009844:Oligosaccharides; D000519:alpha-Galactosidase; D011887:Raffinose