ゲンチオオリゴ糖の工業的生産に関する研究 Industrial Production of Gentiooligosaccharide-Containing Syrups
A β-glucosidase was intensively purified with high recovery from a commercial preparation of Aspergillus niger by consecutive column chromatography. The enzyme was an acidic protein with a p1 of 3.8, and split cellotiose to produce specifically β-D-glucose. Substrate specificity studies demon strated that the purified enzyme required absolutely the C-4 configuration of the terminal, non-reducing-β-D-glucose residues in the substrate molecules.The enzyme synthesized β-glucobiose from D-glucose with high concentration by the condensation reaction. In this reaction, the enzyme specifically required β-glucose as donor substrate . Synthesized β-glucobiose was identified as gentiobiose by PPC and HPLC. On the other hand, β-glucotrioses were synthesized by the transglucosylation reaction when cellobiose and gentiobiose were used as substrates individually. The two main products among these β-glucotrioses were identified as 62-O-β-D-glucosyl cellobiose and gentiotriose by NMR analysis, respectively . The industrial production of gentiooligosaccharide-containing syrups was developed by using both reactions of fungal β-glucosidase. The optimum pH (pH 4.0-4 .5) and temperature (65°C) for the production of β-glucooligosaccharide were fairly close to the optimum conditions of hydrolysis reaction of cellobiose by β-glucosidase. The enzyme (1 .5 units/g-glucose) was incubated with highly concentrated glucose solution (65%, w/w) at pH 4.0 and 65°C for 72 hr, and β-glucooligosaccharide syrup (GentoseR #45) containing about 45% (w/w) of oligosaccharide was produced by the reaction of the enzyme. Furthermore, ?A-glucooligosaccharide syrup (Gentosec #80) containing more than 90% (w/w) of oligosaccharide was fractionated by the cation exchange resin column chromatography using GentoseR #45 as the raw material. These syrups had a bitter taste derived from gentiooligosaccharide, and GentoseR #45 in particular had both the bitter taste and sweet taste of glucose. GentoseR #45 showed the same viscosity as that of sucrose, and that of GentoseR #80 was a little higher than sucrose. The oligosaccharides of these syrups were stable when treated 10 min at pH 3-4 and 120°C or at pH 1-2 and 100°C, and only about 10% (w/w solid) of oligosaccharides was hydrolyzed at pH 1-2 and 120°C . These syrups showed high hygroscopicity and high moisture-retaining activity. Also, these syrups reduced the freezing point of water more than sucrose, and other properties of gentiooligosaccharide-containing syrups such as osmotic pressure and water activity were almost the same as that of sucrose . Moreover, gentiooligosaccharide-containing syrups were not digested by pancreatic a-amylase, and the maximum no-effect level values of both syrups were estimated to be more than 0 .3 g/kg. β-Glucooligosaccharides were selectively utilized by Bifidobacterium spp., Lactobacillus spp. except L. fermentum and L. salivarius group, and Mitsuokella multiacidus group, however, almost all of Eubacterium spp., Fusobacterium spp. and Clostridium peffringens group could not utilize the saccharides. The administration of β-glucooligosaccharides (4 g daily for 10 days) promoted the growth of Bifidobacteria and lowered fecal pH, in vivo. Furthermore, the volunteers never had diarrhea or flatulence and the consistency of feces was improved. From these results, it was presumed that gentiooligosaccharide-containing syrups might be utilized as brand-new oligosaccharides for the improvement of intestinal microflora and widely used for food processing and other additives.
- 応用糖質科学 : oyo toshitsu kagaku = Journal of applied glycoscience
応用糖質科学 : oyo toshitsu kagaku = Journal of applied glycoscience 42(1), 83-89, 1995-03-31