Sugars chemical structure

In the past, research activities in the field of hemicellulose were aimed mainly at utilizing plant biomass by conversion into sugars, chemicals, fuel and as sources of heat energy. However, hemicelluloses, due to their structural varieties and diversity are also attractive as biopolymers, which can be utilized in their native or modified forms in various areas, including food and non-food applications. 

Moreover, an absorption band near 1375 cm-i is detected and it is assigned to the CH bending vibration present in cellulose and hemicellulose chemical structures (Sim et al., 1998). The prominent band at 1044 cm-i is also associated with hemicelluloses and is attributed to the C-OH bending. Finally, a sharp band at 897 cm-i, which is typical of b-glycosidic linkages between the sugar units in hemicelluloses, was detected in the anomeric region (Sun et al., 2005). 

Considerable studies have been done on the effects of the most important chemical and physical factors involved in the degradation of anthocyanins (temperature, light, pH, SO2, metal, sugar, and oxygen) in model systems and food extracts. In addition, anthocyanin concentrations, its chemical structures, and media compositions are fundamental factors influencing stability. 

This paper will not described the chemical structure of pectins which is a difficult problem [1] even if the physical properties in solution and ability to form gel must be directly related with the distribution of the units along the chain. The functional properties of pectins are not only related to the neutral sugar content (up to 15 %) but also to the distribution of structural blocks having very different contibutions. 

Rombouts, F.M. and Thibault, J.F. (1986) Sugar beet pectins chemical structure and gelation through oxidative coupUng. In Chemistry and Function of Pectins, edited by M.L. Fishman, et al, pp. 49-60. American Chemical Society, Washington, DC. 

Interactions studies between some divalents metal ions and pectins from citms and sugar-beet revealed that the chemical structure of the latter, namely the presence of acetyl functions, induces differences of binding process whereas the scale of selectivity was not affected. Some further studies could be carried out on the correlation between the binding mode and the degree of acetylation. Lastly, pectins showed a clear scale of selectivity towards heavy metals with high capacities of binding which make them suitable to be used in waste-waters depollution. 

Fig. 1 Chemical structures of pyrene conjugated at the 5 -end (5 -Py) and the 2 sugar position of uridine (PyU), and phenothiazine conjugated at the 5 -end of ODN (5 -Ptz)...

Did you know the average American consumes the equivalent of 20 teaspoons of sugar each day The non-nutritive sweetener industry is described as a billion-dollar industry with projections of even more rapid expansion in the next few years. What do chemists look for in their search for an ideal sweetener Consumers seek good-tasting, nontoxic, low-caloric sweeteners. Chemists in the sweetener industry add further demands an inexpensive, easy-to-synthesize product that is readily soluble in water and resists degradation by heat and light is of prime importance. The chemical structure of sucralose keeps the sweetener intact as it passes through the acidic environment of the stomach. Thus, sucralose is not... 

HPLC has been employed for the identification and determination of red dyes in confectionery. The chemical structures, commercial names, European Community (CE) number, colour index (Cl) number and name, and food and drug (F and D) name of the red dyes included in the investigation are listed in Fig. 3.30. Dyes were extracted from confectionery by stirring 1.00 g of sugar ball with 10 ml of methanol until the balls were entirely decolourized. The extract was diluted 10-fold with water, filtered and used for... 

Fig. 5.1 Chemical structures of ginsenosides. Ginsenosides can be separated into protopanaxadi-ols (a) or protopanaxatriols (b), depending on the presence or absence of a substituent group at carbon 6. Individual ginsenosides differ according to their sugar moieties, as indicated by Ri and R2 in the table...

DNA (the acronym for deoxyribonucleic acid) is a large molecule having roughly the shape of two spaghetti strands wrapped around each other. The chemical structures for the three kinds of chemical units found in DNA are shown below. These units are a sugar (de-... 

Kosan Biosciences was formed almost 6 years ago, founded on an interest in polyketides, microbial metabolite-based drugs. Polyketides have many diverse chemical structures including erythromycin, which will be mentioned again later. These chemicals include fused-ring aromatic compounds, compounds decorated with sugars, and compounds with large stretches of double bonds. Each of these compounds has different biological activities and utilities, but they are all made in nature by very similar biochemistry. 

They contain 12-, 14-, or 16-membered macrocyclic lactone rings attached to amino acids and/or a neutral sugar moiety attached via glycoside bonds. Beyond this, their individual chemical structures and sizes as reflected by molecular weight are dramatically different. Thus, despite exerting similar mechanisms on bacteria, they are very chemically different from each other. 

Figure 1.86 The chemical structure of the sugars in RNA (ribose) and DNA (deoxyribose). Reprinted, by permission, from M. E. Houston, Biochemistry Primer for Exercise Science, p. 30, 2nd ed. Copyright 2001 by Michael E. Houston.

Several 0-aminoacyl sugars were prepared to study a relationship between taste and chemical structure. Methyl a-D-glucopyranoside, methyl a-D-galactopyranoside and methyl a-D-mannopyranoside were selected as sugar skeletons. As basic amino acids, esters of lysine, ornithine, a,Y-diaminobutyric acid, and a,p-diaminopropionic acid were introduced into 2-0-, 3-0-, and 4-0- positions of sugars leaving only 6-hydroxyl group free. The results of sensory analysis are list in Table VI. O-... 

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