Dextrinization chemistry

The first report in the literature of the isolation of a substance recognizable as a cyclodextrin was that of Villiers which appeared in 1891. From digests of Bacillus amylobacter on potato starch, Villiers obtained a small amount (3 g per 1000 g of starch) of a crystalline material, which he named cellulosine because of its resemblance in some respects to cellulose. The foundations of cyclodextrin chemistry were laid down, however, in the period 1903-1911 by Schardinger, and, in fact, some of the older literature frequently refers to the cyclodextrins as Schardinger dextrins. 

Another common theme that authors use to establish importance involves environmental impacts. For example, an environmental slant is used in the first sentence of the cyclodextrin article (P3, exercise 6.7), where the study of cyclo-dextrins is justified based on their role in soil remediation. The importance of work that benefits air or water quality and/or promotes green chemistry can also be stressed. Work is also viewed as important if it has cross-disciplinary applications. For example, in the Introduction section of the tetrazole article, the authors stress the importance of tetrazoles in coordination chemistry, medicinal chemistry, and in various materials science applications and point out their role as useful intermediates in the preparation of substituted tetrazoles ... 

Dr. French was a prolific contributor of research articles to professional chemical and biochemical journals. He published many reviews and methods articles in Annual Reviews of Biochemistry, Methods in Enzymology, Advances in Carbohydrate Chemistry and Biochemistry, Starch Chemistry and Technology, and The Enzymes. Two articles that were published in this Advances are The Raffinose Family of Oligosaccharides in Vol, 9 and The Schardinger Dextrins in Vol. 12. He was a member of the Editorial Advisory Boards of the Journal of Biological Chemistry and Carbohydrate Research, and of the Board of Advisors for Advances in Carbohydrate Chemistry and Biochemistry. 

Biomimetic Chemistry, including that involved in the synthesis and study of artificial enzymes, has grown to enormous proportions. Even the part of the field using cyclo-dextrins as binding groups in synthetic catalysts that mimic enzymes has been the subject of a large review article [1]. Thus in this chapter I will focus mainly, but not exclusively, on work from our own laboratory. Other chapters will help make up for this somewhat narrow focus. I have published several reviews of our work elsewhere [2-51]. 

The application of enzymes as catalysts in organic chemistry is closely linked to their immobilization. Indeed, many enzymes are only available in an immobilized form. The immobilized enzymes can be used as received, greatly easing their application. Numerous of these readily available immobilized enzymes are now the working horses of biocatalysis. This has even led to the incorrect use of the abbreviation of an enzyme name for a specific enzyme preparation, that is CALB for the immobilized form of Candida antarctica lipase B on cross-linked polymethacrylate (also known as Novozym 435). Vice versa the commercial name of an enzyme preparation-Amano PS-has taken the place of the enzyme (Burkhdderia cepacia lipase on dextrin or diatomaceous earth). Surprisingly, often no attention is paid to the fact that the enzyme is immobilized [1]. 

In 1945, the late C. S. Hudson observed to the author that he considered the Schardinger dextrins and their relationship to starch to be the most perplexing problem in starch chemistry. 

Chemistry of Dextrinization, and Structure of Dextrins and British Gums 302... 

A different chemistry must be involved in the formation of pyrodextrins, that is, the dextrinization of starch in the presence of catalysts. TTie methylation analysis of various pyrodextrins " indicated this well (see Tables... 

Smith and coworkers - have subjected starch dextrins to the classical techniques of structural carbohydrate chemistry. In one study, four commercial maize-dextrins were fractionated from aqueous ethanol to obtain a sub-fraction which was the most resistant to periodate oxidation. This material was then methylated, the product hydrolyzed, and the resulting methylated sugars analyzed by column chromatography. Table II shows the results. The complexity of the dextrin structure is shown by the fact that only components 1, 2, and 5 arise in any large proportion from the methylation of maize starch. It is of interest that no traces of a methyl... 

Next observe micro gerbs of the powder with dextrin. Notice how similar the chemistry is to the wet powder tests. 

The fundamentals of CD chemistry were laid down by Schardinger. In 1903, Schardinger published a report that digesting starch with a microorganism that survived the cooking process resulted in the formation of small amounts of two different crystalline products, dextrins A and B, which were described with regard to their lack of reducing power and seemed to be identical with the cellulosines of Villiers. 

Enzymatic process is the main method to produce cyclodextrins (CDs), and so far, chemical methods have been reported. CD is industrially produced from starch, glucogen, malto-oligosaccharides, and other dextrins through catalysis by cyclodextrin glucosyl transferase (CGTase). More and more researchers focus on the essential CGTase to prepare CD due to its wide applications in food, medicine, cosmetics, environmental protection, and analytical chemistry. 

French, D. (1957). The Schardinger dextrins. Advances in Carbohydrate Chemistry, 12,189-260. 

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