• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.164-172
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• 1989

The formation of galactooligosaccharides by transgalactosidation reactions during hydrolysis of lactose by the ${\beta}-galactosidase$ from Streptococcus thermophilus 510 was investigated. Three oligosaccharides were detected during hydrolysis. It was found that the optimum conditions for the production of oligosaccharides was 40% lactose treated with ${\beta}-galactosidase(50\;ONPG\;units/ml)$ at $37^{\circ}C$ for 4 hours. The oligosaccharides formed accounted for 30% of the total sugars when the lactose had been 94% hydrolysed. 69% of the oligosaccharides were identified as $6-o-{\beta}-D-galactopyranosyl-D-glucose(allolactose)$ and 23% as $6-o-{\beta}-D-galactopyranosyl-D-galactose(isogalactobiose)$. The separation of galactooligosaccharides by the use of Bio-Gel P-2 gel permeation chromatography was also studied.