Fructose 708 Tests

Test tube 2 2-fructose Test tube 3 3-sucrose Test tube 4 4-starch Test tube 5 5-sucrose Test tube 6 6-starch Test tube 7 7-sucrose Test tube 8 8-starch... 

On oxidation of 1 mole of planteose by periodic acid, 4.6 moles of oxidant were consumed, with the formation of 1.8 moles of formic acid (no formaldehyde was produced). After treating the oxidized product with an excess of sodium borohydride, the Seliwanoff test for fructose was negative, though a similarly oxidized and reduced sample of melezi-tose gave a positive fructose test. 

A kit to carry out the sucrose / glucose / fructose test based on the principal outlined above, is available from Boehringer Mannheim. Cat. No. 716-260. 

Molisch s test A general test for carbohydrates. The carbohydrate is dissolved in water, alcoholic 1-naphthol added, and concentrated sulphuric acid poured down the side of the tube. A deep violet ring is formed at the junction of the liquids. A modification, the rapid furfural test , is used to distinguish between glucose and fructose. A mixture of the sugar, 1-naphthol, and concentrated hydrochloric acid is boiled. With fructose and saccharides containing fructose a violet colour is produced immediately the solution boils. With glucose the appearance of the colour is slower. 

Rapid furfural test," Fructose gives an immediate violet coloration on boiling (see Test 4 for glucose). 

Rapid furfural test" A violet coloration is produced immediately on boiling (as for fructose). 

The following simple test distinguishes fructose from all other carbohydrates. Upon heating a little fructose with dilute cobalt chloride solution, cooling and treating with a little ammonia solution, a violet to purple colour is developed, - the colour gradually fades and must be observed immediately after the addition of the ammonia solution. Green cobalt hydroxide is formed with all other carbohydrates. 

The calcium carbonate precipitate was removed by filtration, and the filtered solution was found to contain 1,436 g of fructose as determined by optical rotation. A small amount of calcium bicarbonate was present as an impurity in solution and was removed by the addition of oxalic acid solution until a test for both calcium and oxalic acid was negative. The insoluble calcium oxalate precipitate was removed by filtration. 

Sucrose caramels have been produced under anhydrous thermal conditions that are designed to maximize the content of fructose-rich oligosaccharides.100-102 These sucrose thermal oligosaccharide caramels (STOC) have been tested in animals as a nutritional supplement. Improved weight gains and feed conversion, and increased levels of bifidobacteria (see section VIII) were observed in broiler chickens that were fed this supplement.103... 

Competitive binding studies have shown that 164 and 166 are suitable for the detection of glucose at physiological levels [253-255]. Diboronate 165 is capable of chiral recognition of monosaccharides and gave the best chiral recognition for fructose when tested with a series of different saccharides [255]. 

With the experimental results accumulated during his stay in Berlin, Garcia Gonzalez prepared two doctoral dissertations, entitled New Crystalline Phosphoric Esters of o-Fructose and Tests on Some Assumed Phases of Alcoholic Fermentation, which he presented in order to receive his doctorates in Chemistry and in Pharmacy, respectively, at the University of Madrid in 1932. Armed with these two degrees, he decided to pursue an academic career in his own country. His early training in a provincial... 

It is also interesting that, although the ( )-viboquercitol mixture is sweet, (-)-viboquercitol (96) has only trace sweetness. Therefore, (+)-viboquer-citol (95) would be expected to have a fairly strong, sweet taste, probably close to that of sucrose or o-fructose it has not, however, yet been obtained in pure form to permit testing of the speculation. 

Place 5 mL of the solutions of glucose, fructose, sucrose, and starch into the appropriately labeled test tube, numbered 1 through 4. Add 4 mL of Benedict s solution to each test tube and shake each solution until thoroughly mixed. Place each test tube in the boiling-water bath and heat for... 

By careful choice of both the reaction conditions and the phenolic compound used, it may be possible to produce a colour that is characteristic of a particular carbohydrate or related group, so giving some degree of specificity to the method. Thus, Seliwanoff s test uses hydrochloric acid and either resorcinol or 3-indolylacetic acid to measure fructose with minimal interference from glucose. The colour produced by pentoses with orcinol (Bial s reagent) or p-bromoaniline is sufficiently different from that produced by hexoses to permit their quantitation in the presence of hexoses. However, none of the methods based on the formation of furfural or its derivatives can be considered to be entirely specific. 

Yeast cells are able to metabolize many types of sugars. In this experiment, you will observe the fermentation of sugar by baker s yeast. When yeast cells are mixed with a sucrose solution, they must first hydrolyze the sucrose to glucose and fructose. Then the glucose is broken down in the absence of oxygen to form ethanol and carbon dioxide. You can test for the production of carbon dioxide by using a CBL pressure sensor to measure an increase in pressure. 

Fayolle et al.12 described work done on alcoholic fermentation, wherein they studied the effects of temperature and various calibration methods. The samples were removed and submitted for HPLC and other conventional analyses. The samples were used as is for MIR spectra generation. PLS-1 was used for equation constmction. The test RSDs for glucose, fructose, glycerol, and ethanol were, respectively, 12.5,6.1, 0.6, and 2.9 g/1. The wavelengths assigned to various components were also listed. 

Figure 6.3 Multienzymatic activity test for FSA. G3P D-glyceraldehyde-3-phosphate F6P fructose-6-phosphate PGI phosphoglucose Isomerase G6P glucose-6-phosphate GPD glu-cose-6-phosphate dehydrogenase.

In order to test these assumptions Heathcock prepared different chiral ketones. Thus, the aldol condensation of the fructose-derived ketone and the acetonide of (/ )-glyceraldehyde gave poor results in the double stereodifferentiation, since an almost equal mixture of the two jyn-aldols 68a and 68b were obtained. However, the reaction with the (5)-aldehyde gave only one syn adduct (69a) (Scheme 9.22) ... 

Foulger s test analychem A test for fructose in which urea, sulfuric acid, and stannous chloride are added to the solution to be tested, the solution is boiled, and in the presence of fructose a blue coloration forms. ful, az, test four-degree calorie chem The heat needed to change the temperature of 1 gram of water from 3.5 to 4. j°C. for di gre kal o-re ... 

The starches, the most important vegetable reserve carbohydrate and polysaccharides from plant cell walls, are discussed in greater detail on the following page. Inulin, a fructose polymer, is used as a starch substitute in diabetics dietary products (see p.l60). In addition, it serves as a test substance for measuring renal clearance (see p.322). 

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