Of polysaccharides, preparation

C-n.m.r. spectroscopy is useful in monitoring the purity of polysaccharide preparations. Similarly, in a multicomponent, biological system, such as exists in fungal cell-walls, the varying proportion of each polysaccharide can be gauged, once characteristic signals have been identified. 

Extraclion and Yield of Polysaccharide Preparations from Various Soils... 

Soils (Soil organic mailer, %) Yield of polysaccharide preparations Ref- erences... 

Figure 13. NMR spectra of polysaccharide preparations from various strains...

ANALYTICAL AND PREPARATIVE COLUMNS FOR AQUEOUS SIZE EXCLUSION CHROMATOGRAPHY OF POLYSACCHARIDES... 

Based on this background, a selected number of preparative, semipreparative, and analytical aqueous SEC systems for the analysis of polysaccharides, summarized in Table 16.1, are presented and discussed briefly in this chapter. 

Dextran gels have been utilized since the late 1950s (1) for the separation of biopolymers. First attempts on Sephadex (2-5) and Sephadex/Sepharose (6-8) systems are documented for hydrolyzed and native starch glucans. Up until now, particularly for the preparative and semipreparative separation of polysaccharides, a range of efficient and mechanically stable Sephacryl gels (9-14) have been developped. 

Separations of polysaccharides by fractionation on a preparative scale were also examined. Stemming from earlier work in his laboratory on the isolation of acidic polysaccharides by precipitation as their insoluble Cetavlon salts, Stacey and coworkers showed that it was possible to fractionate neutral polysaccharides by selective precipitation with Cetavlon after the formation of borate complexes. 

Barbosa, M.I. Borsarelli, C.D. Mercadante, A. Z. (2005). Light Stability of Spray-Dried Bixin Encapsulated with Different Edible Polysaccharide Preparations. Food Research International,Vol. 38, No. 8-9, (October-November 2005), pp 989-994, ISSN 0963-9969. 

Barbosa, M.I.M.J., BorsareUi C.D., and Mercadante, A.Z. Light stability of spray-dried bixin encapsulated with different edible polysaccharide preparations, Food Res. Int., 38, 989, 2005. 

The total polysaccharide preparations from wine, apple and tomato juices were analysed in our HPSEC system. The obtained profiles (Figure 2) were all characterized by the presence of a main sharp peak eluted at the same elution volume (18.2 to 18.6 min) as a previously purified wine RG-II [20]. 

A traditional system for the preparation of table olives, involves a treatment of the fresh fruit with a solution of NaOH to hydrolised the bitter glycoside oleuropein, followed by a lactic fermentation in brine. The modifications that take place on pectic polysaccharides of olives (Manzanilla variety) during this process was smdied. Processing induced a net loss of polysaccharides soluble in sodium carbonate and a paralel accumulation of water and Imidazole/HCl soluble polysaccharides. A general decrease of the apparent molecular weight of water and carbonate soluble polysaccharides was also detected. 

A variety of sulfating agents has been used for preparing sulfuric esters of polysaccharides.297 - 303 The methods employed include use of adducts of sulfur trioxide with such aprotic solvents as triethylamine,299 dimethyl... 

Because pH, ionic strength, time-of-aging, and water content are widely variable parameters in a field preparation of polysaccharide... 

Tarr and Hibbert27 determined the optimal conditions for the preparation of dextran. Sucrose was found to be the only suitable carbohydrate substrate, although some strains produced a small amount of dextran from D-glucose. The formation of dextran from D-glucose had been observed occasionally by earlier workers, but such formation is of somewhat transient character, occurring only when the cultures are very active with respect to the formation of polysaccharides from sucrose.27 The nutrient solution (pH 8.0) used by Tarr and Hibbert27 for dextran... 

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