Polysaccharides fructans

Phytochemistry The roots and aboveground plant parts contain oligo- and polysaccharides (fructan), pectic substances, and hemicellulose (Turdumambetov 1995 Turdumambetov et al. 2007). The fruits contain lipids, hydrocarbons, triterpene alcohols, sterols, mono- and diacylglycerides, etc. The predominant fatty acids are 16 0,18 1, and 18 2 (Ul chenko et al. 

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... 

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-... 

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. 

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. 

Fructans are polysaccharides composed of o-fructofuranose units. They are important in short-term energy reserves for grasses and some plants. Inulin, found in dahlias, and levans from grasses are examples of fructans. Levans are short linear polysaccharides composed of (3 2 1 linked fructose units as illustrated in structure 9.21. 

It should be determined whether any of these factors is large enough to constitute a significant interference in the planned experiment. See also the comments on NDF below. An NDF method which includes pectic polysaccharides, P-glucans and fructans has been published by Hall et al. (1997). 

Polyfructosans. See Fructans. Polyglycosiduronic acids. See Glyco-siduronic acids, poly-. Polysaccharides. See also, Carbohydrates,... 

Some polysaccharides, for instance glucans, fructoglucans, or fructans, can be produced by either thermal or biocatalyzed polymerization.237 245,336 Such polysaccharides are complementary to all other natural or engineered polysaccharides for which a vast number of applications are known. Poly-... 

Inulin was identified as a major (5.9%) component of the roots of E. angustifolia (Heyl and Stanley, 1914). Giger et al. (1989) noted that polymerization of fructans occurred over the course of winter as observed by the reduction in fructose from October and May. The rate of polymerization was faster in E. purpurea than E. angustifolia, suggesting that other polysaccharides may develop in a similar manner. Additional research is needed to identify the effects of harvest time on polysaccharide composition. 

The malleable term hemicellulose in the title of this Chapter refers to all of the types of polysaccharide in the Gramineae, other than celluloses, starches, and fructans. The term implies nothing concerning the nature of the polysaccharides, their biological role, or their location in the plants. 

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-... 

Fructofuranose is found in probably the most well-known and commercially available of all carbohydrates, sucrose. Various derivatives of sucrose are also known in nature, e.g. fatty acid derivatives [91] and agrocinopines [92]. Fructo-furanosides are also present in various plant and bacteria polysaccharides, most often as fructans, but sometimes as a singular component in repeating units [2, 93]. Syntheses of sucrose or derivatives thereof are not very frequent [41, 94-96], and oligosaccharide synthesis with fructofuranosyl donors are even more scarce. 

Polysaccharides that exclusively contain D-fructose are known as fructans and there are two known kinds, inulin and levan. Inulin is a polysaccharide containing -D-fructofuranose linked (2 1) [118]. Inulins are found in the roots and tubers of the family of plants known as the Compositae, which includes asters, dandelions, dahlias, cosmos, burdock, goldenrod, chicory, lettuce, and Jerusalem artichokes. Other sources are from the Liliacae family, which includes lily bulbs, onion, hyacinth, and tulip bulbs. Inulins are also produced by certain species of algae [119]. Several bacterial strains of Streptococcus mutans also produce an extracellular inulin from sucrose [120]. 

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