Thursday, June 13, 2019

Carbohydrate Essay Example | Topics and Well Written Essays - 2000 words

Carbohydrate - Essay ExampleThe apparent simplicity of these processes proved deceptive. The number of chemically definable units increased with accelerated speed from the beginning of the nineteenth century. Toward its end, the very multiplicity which sometimes became confusing made it possible to sort out many problems. The genius of the great natural philosophers of earlier times had its successors in the genius of chemists who constructed a new unity by fitting together ruin pieces of special experience. At first, however, the organismic products had to be taken apart and transferred from a biological system to that of elements and molecules.In 1827 William Prout (1785- 1850) distinguished between three groups of food materials fats, proteins, and chicken feeds. From the fire of sugars which he carried out he concluded that sugars are related to starch and characterized by containing oxygen and hydrogen in the proportions in which these elements are present in water. They ar e hydrates of carbon, or carbohydrates.The conversion of starch into the sugar found in grape juice (glucose) was carried out by Gottlieb Sigismund Kirchhoff, a German pharmacist in Russia, in two ways by heating with dilute sulfuric acid or by digesting with the gluten of malt (1811, 1814). Glucose was also obtained by the action of certain(prenominal) specific plant extracts on significations like amygdaline or salicin. Latirent proposed to call these substances glucosamides (1852) which Gerhardt simplified to glycosides. They are split by enzymes into glucose and such complex materials as the cyanide of benzaldehyde (Foster-Powell, K., Brand Miller, 1995). When Alexander Butlerow (1828- 1886, Kasan) subjected a new substance, which was later found to be formaldehyde, to a digestion with limewater, he obtained (1861) the first example of the synthetic production of a substance which behaves like a sugar. Baeyer explained this reaction (1870) as starting from a hydrate of formald ehyde, CH 2 ((OH) 2, and consisting of a combination of six such molecules with removal of six molecules of water. The sugar thus had the formula COH(C OH H) 4.CH 2 0H. This speculation used the results of an investigation of mannit, an alcohol obtained from manna. Berthelot, as a sequence of his work on the tribasic alcohol glycerine, recognized mannit as a hexabasic alcohol 1860) its reduction to the hydrocarbon hexane, by means of hydroiodic acid, proved the arrangement of the carbon atoms in a straight chain. This proof, in turn, was possible only because of the equation of this hexane with other hydrocarbons. A. Wurtz applied his findings of aldehyde condensations, in which only two aldehyde molecules were involved, to the problem of the constitution of glucose. Oxidations to sugar acids and reduction to mannit were further helps in solving the problem. The chemical constitution of fructose, which is feature with glucose in cane sugar (sucrose), could be interpreted (1880) fr om the acids obtained by oxidizing the addition compound with hydrocyanic acid (Foster-Powell, Miller, 1995). Cellulose also belongs to the group of carbohydrates, since the addition of molecular water, under the regulate of strong sulfuric acid, converts it into glucose (Braconnot, 1819). Wood contains a large proportion of cellulose and lignin. The two call be separated, according to Anselme Payen ( 1795- 1871,

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.