On formation and chemical structure of functional oligasaccharide from lactose

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Di-, tri-, tetra-, penta- and hexasaccharides were formed during the hydrolysis of lactose by transgalactosylation reaction of Aspergillus oryzae <beta> -galactosidase. In this study the isolation and characterization of the major constituents of tri-, tetra- and pentasaccharides are described. The structure elucidation of 3 tri-, 2 tetra- and 1 pentasaccharides was carried out by methylation analysis, mass spectrometry and <^(13)C> -nmrspectrometry. The trisaccharides are 3'-galactosyl-lactose, 6'-galactosyl -lactose and 4,6-digalactosyl-glucose. Tetrasaccharides are O- <beta> -D-galacto pyranosyl-(1-6)-O- <beta> -D-galactopyranosyl-(1-6)-O- <beta> -D-galactopyranosyl-(1-4)-D-glucose and O- <beta> -D-galactopyranosyl-(1-6)-O- <beta> -D-galactopyranosyl-(1-3) [or O- <beta> -D-galactopyranosyl-(1-3)-O- <beta> -D-galactopyranosyl-(1-6)]-O- <beta> -D-galactopyranosyl-(1-4)-D-glucose. Pentasaccharide is O- <beta> -D-galactopyranosyl-(1-6)-O- <beta> -D-galactopyranosyl-(1-6)-O- <beta> -D-galactopyranosyl-(1-4)-D-glucose.