Carbohydrate analytical aspects

Hizukuri, S. 1995. Starch Analytical aspects. In Carbohydrates in Food (A. C. Eliason, ed.), pp. 347-429. Marcel Dekker, New York. 

Hizukuri S. Starch analytical aspects. In Carbohydrates in Food. 

Much of the research on the l.c. of carbohydrates has focused on analytical, rather than preparative, aspects. In reality, however, the conditions found in the majority of l.c. methods, namely, no sample derivatization, high-resolution separations, and nondestructive detection-techniques, are ideal for the preparation of pure molecules. Thus, most of the analytical l.c. methods previously described can also be used to isolate small quantities of pure compounds. This Section will cover the use of analytical-scale equipment for preparative applications, as well as the use of large-scale and dedicated preparative instruments for this purpose. Prior to discussion of these applications, a general overview of the preparative l.c. of carbohydrates will be given. 

Some factors will condition the choice of the cleanup procedure, namely (a) the extraction solvent used in the previous stage, (b) the concentration of the carbohydrates present in relation to potential interfering compounds, and (c) the complexity of the analyzed food. Additionally, the nature of these interferents and the need to minimize the loss of analyte during the cleanup will become key aspects to be considered. In any case, and regardless of the final method chosen, it is essential that the percentage recovery of the cleanup procedure be determined. The most frequently utilized procedures will be commented next. 

The first two sections of this book provide the reader with a background on the thermal generation of aromas. Included in these sections are perspectives on the regulatory aspects and the analytical methodologies at the forefront of aroma research. Subsequent sections present original research on aromas derived from various food sources. In addition, we have included a section on mechanistic studies to provide insights into aroma formation through thermal decomposition of lipid, carbohydrate, and amino acid precursors. The final section is entirely... 

The importance of zinc to growth and development in all forms of life was first established through zinc deficiency studies of microorganisms followed by those in plants and animals see Nutritional Aspects of Metals Trace Elements) The involvement of zinc in a wide variety of metabolic processes including carbohydrate, lipid, protein, and nucleic acid synthesis and degradation paralleled the technical advances in analytical methods that could detect the presence of zinc in minute amounts coupled with advances in the methodology for protein isolation and purification. 

This review covers the formation, composition, structure, function and properties of the acquired pellicle. Specifically, the formation of pellicle is considered in terms of thermodynamic and kinetic aspects. The composition of the pellicle is reviewed in terms of the proteins, carbohydrates and lipids that have been identified using a range of analytical techniques. The ultrastructure of the pellicle is described in some detail from studies involving enamel slabs carried in the mouth, in which the subsequent pellicle was analysed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). The function of the pellicle is outlined in terms of its lubrication properties, its ability to act as a semi-permeable membrane and its overall protection of the underlying enamel surfaces. Since pellicle is formed at the interface between the enamel surface and the oral environment, the important process of bacterial attachment to the pellicle surface is described and the specific bacterial binding sites found in the pellicle are summarised. The influence of diet and nutrition on the pellicle layer is considered. The formation of extrinsic stain is discussed in particular, the role that chlorhexidine... 

E. Bourquelot was a careful analyst. The practical aspects of analytical chemistry occupy a high place in the teaching of pharmacy, and important competitive examinations, such as the one for hospital pharmacists, include a practical examination in analysis. Bourquelot was to keep this analytical orientation in his research, he always made appeal to analytical determinations. It was often the comparison of results obtained by different techniques which permitted him to make some of his finest discoveries. He was one of the first carbohydrate chemists to link together, in an extended manner, the techniques of physical measurement with those of chemical determination. 

The development of electrochemical procedures for industrial synthesis of alditols was initiated in the 1920 s and the literature on electrochemistry of carbohydrates, from both synthetic and analytical viewpoints, is extensive. However, it is probably true to state that the average carbohydrate chemist has scant knowledge of the literature on preparative aspects of electrochemistry, or on polarography of sugars. The Chapter by Fedoronko (Bratislava) should, therefore, fill an important need by integrating the work on the electrochemistry of carbohydrates that has matured during several decades. 

Not only are the technical aspects of sample taking important, but so also is the timing of this operation in order to maximize the usefulness of the analytical results, and, in fact, strict rules (e.g. use of the fasting value) for analyses performed in the course of investigations into the metabolism of fats and carbohydrates have been routinely followed for many years. 

R 52 A. Gergely, K. Gyimesi-Forras, P. Horvath, S. Hosztafi, J. Koekoesi, P.I. Nagy, G. Szasz and A. Szentesi, 6-Oxo-Morphinane Oximes Pharmacology, Chemistry and Analytical Application , p. 2555 R 53 M. Hricovini, Structural Aspects of Carbohydrates and the Relation with Their Biological Properties , p. 2565 Vol. 12, 2005... 

About the same time, a new international research journal, Carbohydrate Research, appeared (volume 1) in 1964. It has become the principal journal for the publication of all aspects of carbohydrate research, such as chemical synthesis and modification enzymatic synthesis organic and enzymatic mechanisms involving carbohydrates carbohydrate metabolism conformational analysis isolation of carbohydrates from natural sources analytical methods chemistry of monosaccharides, oligosaccharides, and polysaccharides biological function of carbohydrates and physical properties. Approximately four to five volumes are published each year. 

About the same time (1981), another international journal. Carbohydrate Polymers, was introduced. Its emphasis is on technical aspects of industrially important polysaccharides. It covers the study and uses of industrial applications of carbohydrate polymers in foods, textiles, paper, wood, adhesives, and pharmaceuticals and includes topics concerning structure and properties biological and industrial development analytical methods chemical, microbiological, and enzymatic modifications and interactions with other materials. 

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