Fructan

The spores of Aspergillus sydowi contain an enzyme system that converts sucrose into a fructan having a structure comparable to that of inulin. The polysaccharide is cleaved by )8-D-(2 1)-fruc-tanases, whereas it is unaffected by /3-D-(2 6)-fructanases. Oligo- 

Two tests based on detection of chitosan sulfonate, namely, the x-ray method and specific enzymolysis, are used in the characterization of chitin, and these have been evaluated in a detailed fashion by Foster and Webber, and by Brimacombe and Webber. Another (less reliable) method involves isolation or chromatographic detection - of the 2-amino-2-deoxy-D-glucose formed on acid hydrolysis of suspected chitin. 

Methods used for the preparation of chitin from lobster shell are equally applicable to fungi. Successive extraction with aqueous acid and hot, aqueous alkali leaves chitin as an insoluble residue. 

This method, which is similar to that used by ScholP in 1908 for the preparation of fungal chitin, sometimes gives rise to an impure product, and additional measures must then be taken to remove contaminants. 

Phycomyces blakesleeanus is of particular interest, as its mycelium contains chitin and acid-soluble chitosan, which is precipitated by neutralization. 

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From the organochemical point of view, carbohydrates/polysaccharides are more or less substituted polyhydroxy aldehydes (e.g., glucose—>glucans) or polyhydroxy ketons (e.g., fructose-n fructans). From the physicochemical point of view, an enormous heterogeneity also exists in... 

Degree of polymerization distribution of a plant fructan (inulin) at increasing physiological age of the source remarkable performance of S-200 in the low dp range degree of polymerization distribution obtained from bad (P-6) and good (S-200 / P-6) resolution of high dp components... 

Bio-Gel P-6 and a combined system of P-6/S-200 were utilized for investigations of inulin-type /3(2- l)-linked nb fructans. With a flow rate of 0.33 mP min, each separation of a sample volume of 1 ml of a 20- to 30-mg/ml concentrated solution typically lasted 20 hr, i.e., one run per day. Both systems (P-6 and P-6/S-200) maintained stability for approximately 1 year, equivalent to approximately 100 runs. 

The remarkable performance of P-6 in the separation of oligosaccharides, particularly of glucans and fructans, is well known (31,32) and is illustrated... 

The biosynthesis and degradation of fructans by microbial organisms has been reviewed in detail recently.35 Additionally, a review of the production of di-D-fructose dianhydrides from inulin and levan by enzymes has been published in Japanese.36 This account is therefore limited to a general overview. 

Little information is available on the specific control of fructan metabolism in higher plants73 or in microorganisms.35 If a regulatory role is envisaged for the di-D-fructose dianhydride enzymes, as has been suggested for microorganisms,71 then more detailed studies are required. 

Two extracellular D-fructans, (2- 6)-linked S-D-fructofuranan or levan and the less common corresponding (2 l)-linked polysaccharide, of the inulin type, are elaborated by different bacteria. These polysaccharides are formed from sucrose by the action of sucrose fructosyltransferases. Terminal )S-D-fructofuranosyl groups are present in some bacterial heteropolysacchar-... 

The idea that inulin-type fructans are fermented by bacteria colonising the large bowel is supported by many in vitro (both analytic and microbiological) and in vivo studies, which, in addition, confirm the production of lactic and short-chain carboxylic acids as end products of the fermentation (Tanner, 2005). Furthermore, it was shown inhuman in vivo studies that this fermentation leads to the selective stimulation of growth of the bifidobacteria population, making inulin-type fructans the prototypes of prebiotics (Roberfroid, 1997 Roberfroid, 2001). 

Interestingly, W271N synthesized larger fructan products as compared to the WT enzyme.97 B. megaterium LS residue Asn252 (subsite +2) clearly plays an important... 

B. C. Tungland, Fructooligosaccharides and other fructans, in G. Eggleston and G. L. Cote, (Eds.), Oligosaccharides in Food and Agriculture, ACS Symp. Ser., Vol. 849, American Chemical Society, Washington, DC. 

From sedimentation and diffusion measurements, Ogston has determined the molecular weight of the fructans from both leafy cocksfoot grass (Dacty-lis glomerata) and Italian rye grass (Lolium italicum) to be 5,500.261 Both polysaccharides were polymolecular, and the data indicated a singly-branched structure for each. 

Stahl, B. Linos, A. Karas, M. Hillenk-amp, F. Steup, M. Analysis of Fructans From Higher Plants by MALDI-MS. Anal Biochem. 1997, 246, 195-204. 

Polymers of D-fructose are important carbohydrate reserves in a number of plants. Inulins and levans are two major types that differ in structure. D-Fructans require only relatively mild conditions for their hydrolysis, for example, levan was qualitatively hydrolyzed by hot, dilute, aqueous oxalic acid. Permethylated fructans could be hydrolyzed with 2 M CF3CO2H for 30 min at 60°. Fructan oligosaccharides were hydrolyzed in dilute sulfuric acid (pH 2) at 70 (see Ref. 53) or 95° (0.1 M). D-Fructans from timothy haplocorm (where they comprise 63% of the water-soluble carbohydrates) could be hydrolyzed with 0.01 M hydrochloric acid at 98°. 

A fructan-produclng bacterium was Isolated from soils and characterized for polysaccharide synthesis. The composition and properties of the polysaccharide produced were studied. The organism. Identified as a strain of Bacillus polvmvxa. produced a large quantity of polysaccharide when grown on sucrose. 

The polysaccharide consisted entirely of fructose methylatlon analysis showed that the primary fructose linkages were P(2- 6) fructofuranosyl linkages. Carbon 13 nmr showed the product to be a levan type fructan. 

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