Polyfructoses

Among other polysaccharides studied were those elaborated by Neisseria per-flava (starch-type polysaccharide), Polytomella coeca (a starch richer in amy-lopectin than most natural starches), Pseudomonas morsprunorum (Wormald) (levan), Acetobacter acetigenum (cellulose), Aerobacter aerogenes (NCTC 8172) (Klebsiella Type 164), Bacillus megaterium. Bacterium pruni, and Bacterium prunicola (polyfructoses of the levan type). 

The catalyzed telomerization of butadiene has been applied to other polysaccharides such as inulin (22) (Fig. 20) which is a polyfructose extracted from Jerusalem artichokes (tuber) or from chicory (roots). This soluble polymer is easily telomerized under mild conditions and the degree of substimtion is also dependent on the reaction conditions [20] (Fig. 20). 

Polyfructoses are widely distributed as reserve food materials in plants. Usually these water-soluble polysaccharides can be extracted from their sources (e.g., tubers) without use of drastic reagents, since they are found in solution in cell sap. 

Bacterial levans, as distinct from other polyfructoses, may be molecules possessing highly branched structures and very high molecular weights. 

The story of the discovery of chromatography is classical [16,17]. A most lucid analysis of Tswett s work from the point of view of the preparative applications of chromatography, has been written by Verzele and Dewaele [18]. The Russian botanist Tswett discovered arormd 1902 that plant pigments could be separated by eluting a sample of plant extract with a proper solvent on a column packed with a suitable adsorbent [1]. Did he name the technique chromatography because it separates pigment mixtures into a rainbow of colored bands, or because "tswett" means color in Russian, or both Nobody knows. What is remarkable, however, is the extreme care with which Tswett selected the adsorbents he used [19-21]. For the famous separation of a- and j3-carotenes, he tried 110 different adsorbents and selected inulin (a water-soluble polyfructose plant reserve material) as the... 

Another effective graft copolymer is hydrophobicaUy modified inuUn this is a linear polyfructose chain A (with degree of polymerisation >23) onto which several alkyl chains have been grafted. The polymeric surfactant adsorbs onto several alkyl chains via multipoint attachment. 

In polyfructoses, a distinction can be made between the inulin (dahlin) group with 1,2-glycosidically linked fructose units and the phlean group with 2,6-glycosidic bonds. Polyfructoses occur as food reserve material in the roots, leaves, and seeds of various plants. In addition, they are produced by certain kinds of bacteria, e.g., laevans, which belong to the phlean group. 

The polyfructose content of grasses alters in the course of the year for example, it passes through a maximum in about the middle of May and then falls again. In contrast, the cellulose content continually increases. Since cattle, unlike humans, can digest cellulose, but prefer not to eat it, and since the food value falls as the cellulose content increases, the grass is cut toward the middle of May. 

Strong hydration of the linear polyfructose chains both in water and in the presence of high electrolyte concentrations and high temperatures. This ensures effective steric stabilization (see the following). 

However in the presence of electrolyte, inulin and PEO show different behavior. With PEO, the cloud point becomes below 60°C when the NaCl concentration exceeds 2 mol/dm NaCl and 0.5 mol/dm MgS04. With inulin, no cloud point could be measured up to 4 moFdm NaCl or 1 mol/dm MgS04. This indicates that the inulin chain (polyfructose) retains its hydration to much higher tanperature and electrolyte concentrations when compared to the PEO chains, and this is probably the reason for the high stability obtained when using inulin carbamates as emulsion stabilizers. 

Another graft copolymer that could be used for stabilization of suspensions is that based on a polyfructose backbone on which several alkyl groups have been grafted (INUTEC SPl), mentioned earlier for stabilization of emulsions. This polymeric surfactant was used to investigate the stability of polystyrene (PS) and PMMA suspensions in the presence of electrolytes [NaCl, CaClj, and Al2(S04)3l [25]. The polystyrene latex was prepared by emulsion polymerization without surfactant, and it was fairly monodisperse, with a diameter of 210 nm. The PMMA latex was prepared... 

Recently, a novel graft copolymer based on a naturally occurring polysaccharide, namely Inulin (polyfructose), has been synthesised [17]. Inulin is a polydisperse... 

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