초록
<P>The prebiotic effects of GOS (galactooligosaccharides) are known to depend on the glycosidic linkages, degree of polymerization (DP), and the monosaccharide composition. In this study, a novel form of alpha-GOS with a potentially improved prebiotic effect was synthesized using bifidobacterial alpha-galactosidase (alpha-Gal) purified from recombinant Escherichia coli. The carbohydrate produced was identified as alpha-D-galactopyranosyl-(1 -> 6)-O-alpha-D-glucopyranosyl-(1 -> 2)-[alpha-D-galactopyranosyl-(1 -> 6)-O-beta-D-fructofuranoside] and was termed stachyobifiose. Among 17 nonprobiotics, 16 nonprobiotics showed lower growth on stachyobifiose than beta-GOS. In contrast, among the 16 probiotics, 6 probiotics showed higher growth on stachyobifiose than beta-GOS. When compared with raffinose, stachyobifiose was used less by nonprobiotics than raffinose. Moreover, compared with stachyose, stachyobifiose was used less by Escherichia coli, Enterobacter cloacae, and Clostridium butyricum. The average amounts of total short-chain fatty acids (SCFA) produced were in the order of stachyobifiose > stachyose > raffinose > beta-GOS. Taken together, stachyobifiose is expected to contribute to beneficial changes of gut microbiota.</P>