抄録
α-Linked galactooligosaccharide (α-GUS) B was produced from lactose hydrolyzates by reverse reaction of hydrolysis of α-galactosidase from Candida guilliermondii H-404. The reaction mixture (2300 ml), containing 1 .93 kg lactose hydrolyzates and 400 g wet cell (62 U/g-galactose) was incubated at pH 4.5 at 50°C for 87 hr. From the reaction mixture, 350 g of α-GUS B was obtained by active carbon chromatography. α-GOS B contained 84% disaccharides and 15% oligosaccharides (mainly trisaccharides). The solubility of α-GOS B was 82% (w/w) or above at 25°C. The sweetness of α-GUS B was about 30% of that of sucrose. It was stable both at neutral pH (pH 7. 0, 80°C, 2 hr), and at acidic pH (pH 3. 0, 80t, 2 hr), and at temperatures up to 180°C (pH 4. 5, 10 min), and on long-time storage (pH 3 .0 and 7. 0, 25°C and 60°C, 3 months). The powder preparation was highly hygroscopic, and its solution showed higher activity of retaining moisture than sucrose. The water activity of α-GUS B was 0.83 (25°C, 70% (w/w)), α-GUS B was not hydrolyzed in an in vitro digestion method, and had activity to inhibit the synthesis of insoluble glucan from sucrose . α-GUS B had also strong selective growth activity for Bifidobacterium. α-GUS A was also produced from only galactose, and was compared with α-GUS B. But there were no large differences with respect to all properties tested.
