著者

松本 圭介 小林 洋一 田村 なつ子 渡辺 常一 菅 辰彦

出版者

The Japanese Society of Applied Glycoscience

雑誌

澱粉科学 (ISSN:00215406)

巻号頁・発行日

vol.36, no.2, pp.123-130, 1989-06-30 (Released:2010-06-28)

参考文献数

28

被引用文献数

5 5

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β-Galactosidases (lactases) from various origins give different kinds of linkage and size of oligosaccharides. In the first chapter, enzyme sources, mechanism of transgalactosylation reactions, and structures of oligosaccharides were briefly introduced. Galactooligosaccharides (TOS) which consist of tri, tetra-, penta-, and hexasaccharides were formed from lactose by transgalactosylation reactions of Aspergillus oryzae β-galactosidase.TOS were a non-absorbable sugar and selectively utilized by all of the Bifidobacterium species in vitro. Administration of TOS caused remarkable increase in the number of Bifidobacterium and decrease in the number of Bacteroides in fecal flora. The improvement of intestinal microflora by TOS led to the suppression of putrefaction in the gut. It was concluded that TOS were a superior bifidus growth-promoting factor. For the large-scale production of TOS, the optimum conditions of transgalactosylation reactions and the manufacturing process were investigated. The amount of TOS were increased together with increase in initial lactose by A. oryzae S-galactosidase, and the maximum TOS formed were 30% by weight of total sugar. After transgalactosylation reactions with A .oryzae enzyme, second reactions with Streptococcus thermophilus β-galactosidase gave rise to TOS content and to sweetness, which were of a desirable sugar composition for food applications. A, oryzae β-galactosidase was immobilized by glutaraldehyde crosslinking on the ion-exchange resin for the continuous production of TOS. Half-life of this immobilized enzyme was 192 days at 55°C. High-grade TOS could be obtained from the reaction mixture by chromatographic separation with sodium-form cation-exchange resin.