Hydrolysis, acid, carbohydrates polysaccharides

De Ruiter, G. A., Schols, H. A., Voragen, A. G. J., and Rombouts, F. M., Carbohydrate analysis of water-soluble uronic acid-containing polysaccharides with high-performance anion-exchange chromatography using methanolysis combined with TFA hydrolysis is superior to four other methods, Anal. Biochem., 207, 176, 1992. 

Finally, this section would remain incomplete without a few comments on the applications of HPLC to a particular group of carbohydrates—polysaccharides—whose determination, both qualitatively and quantitatively, has received much less attention than the rest (56). This may be surprising when the importance of these compounds, in terms of both functional properties and nutrition, is considered, but it is not so surprising when the difficulty of the analyses required is studied. High-performance LC can be used in this field, either to characterize the polysaccharides per se or to study their carbohydrate composition and the nature of bonding after acid or enzymic hydrolysis. 

A. Karlsson and S. K. Singh, Acid hydrolysis of sulphated polysaccharides. Desulphation and the effect of molecular mass, Carbohydr. Polym., 38 (1999) 7-15. 

Carbohydrates. The two functional groups subject to hydrolysis in wood polysaccharides are the ester and acetal linkages, of which the acetals are more important because of their greater abundance and their role in connecting the monosaccharides in the polymers. Hydrolysis may take place under both acidic and alkaline conditions. The extent and consequences of acid hydrolysis are greater. 

Carbohydrates are divided into groups depending on how many monomers are combined by condensation polymerization monosaccharides (Latin saccharum, sugar ), disaccharides, trisaccharides (etc.), and polysaccharides. Monosaccharides are simple sugars that cannot be broken down into smaller carbohydrate units by acid hydrolysis. In contrast, hydrolysis of a disaccharide or trisaccharide yields two or three monosaccharides (either the same or different), while complete hydrolysis of a polysaccharide produces many monosaccharides (sometimes thousands of them). 

Polyethylene (Section 6 21) A polymer of ethylene Polymer (Section 6 21) Large molecule formed by the repeti tive combination of many smaller molecules (monomers) Polymerase chain reaction (Section 28 16) A laboratory method for making multiple copies of DNA Polymerization (Section 6 21) Process by which a polymer is prepared The principal processes include free radical cationic coordination and condensation polymerization Polypeptide (Section 27 1) A polymer made up of many (more than eight to ten) amino acid residues Polypropylene (Section 6 21) A polymer of propene Polysaccharide (Sections 25 1 and 25 15) A carbohydrate that yields many monosacchande units on hydrolysis Potential energy (Section 2 18) The energy a system has ex elusive of Its kinetic energy... 

Nicotinic acid is found in plants associated with both peptides and polysaccharides. For example in wheat bran, two forms are described a peptide with a molecular weight of approximately 12,000 and a carbohydrate complex that is called niacytin. Polysaccharides isolated from wheat bran have been found to contain 1.05% nicotinic acid in bound form. Hydrolysis yielded a fragment identified as P-3-O-nicotinoyl-D-glucose (25). 

For the most part, low molecular weight carbohydrates of commerce are made by depolymerization via enzyme- or acid catalyzed hydrolysis of polysaccharides. Only sucrose and, to a very much lesser extent, lactose, both disaccharides, are commercial low molecular weight carbohydrates not made in this way. 

The Wassermann substance17 is prepared by extracting various animal organs, particularly beef heart, with alcohol, and its lipidal nature was early recognized. Pangborn174 described the preparation of a new phospholipid termed cardiolipin from beef heart and claimed that it was the essential constituent of the Wassermann substance. On hydrolysis it gave a fatty acid and a phosphorylated polysaccharide. In a later communication17 however, the carbohydrate constituent is stated... 

Many plants store carbohydrates in their tubers in the form of polysaccharides which upon acid hydrolysis yield D-fructose as the main product. These polysaccharides differ from one another in the size of the molecule as well as in the position of the linkages between the D-fructose residues. Polyfructosans have also been prepared by enzymic action on sucrose. 

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