Fructose colorant from

During the formation of colorant from D-fructose at pH 7.0,73 the first changes in the absorption spectrum occur at 210-240 mu and at 270-290 m/x. Judging by the data in Table II, these peaks are occasioned by a 2-furaldehyde derivative, possibly 5-(hydroxymethyl)-2-furaldehyde, or a compound of equivalent conjugation. Later, the absorption at 350-400 m/x increases. With further reaction, these peaks tend to be smoothed out to a hyperbolic curve, and absorption in the visible range appears and, still later, the solution becomes turbid as well as colored. If the process is continued, brown-to-black material is precipitated. 

Liquid glucose is an aqueous solution of several compounds, principally dextrose, dextrin, fructose, and maltose, with other oligosaccharides and polysaccharides. It is a colorless, odorless, and viscous sweet-tasting liquid, ranging in color from colorless to straw-colored. 

Note The dipping solution, which can also be used as a spray solution, can be employed with silica gel, kieselguhr, cellulose, RP, NH2 and CN phases. Sugars (exceptions include, for example, fructose, melezitose and raffinose) yield brilliantly colored zones on an almost colorless background when the spray solution is employed. Aldohexoses appear brown, aldopentoses bright red and hexuronic acids orange in color [3]. The detection limit differs for different substances it ranges from 10 ng (pyridoxal) over 100 ng (cinnamaldehyde) up to 2 pg (citral). 

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 ... 

D-glucose, and 5-(hydroxymethyl)-2-furaldehyde with anthrone lends support to these conclusions, and further indicates the complexity of the overall reaction. In the reaction of either D-fructose or 5-(hy-droxymethyl)-2-furaldehyde with anthrone, at least nine compounds were observed, three of which were condensation products of anthrone itself. The other products had absorption maxima ranging from 490 to 770 nm (in sulfuric acid solution and under the conditions of the anthrone reaction). One of the prominent pigments, having a blue color ( max 620 nm) and a postulated structure corresponding to compound 123, was isolated and characterized by its nuclear magnetic... 

Bees collect the mannas or honeydews from these sources when nectar is not readily available, and process it to a product which, as already mentioned, is darker in color, lower in D-glucose and D-fructose, and higher in pH, oligosaccharides, total free acid, ash, and nitrogen than the original honeydew. 

Pentosans. These compounds are polysaccharides which may he considered as anhydrides of pentose sugars, after the manner of the hexosans. sucrose, starch, from glucose, fructose. When pentosans or pentoses are heated with hydrochloric ot sulfuric acid, furfural C fljO CHO is formed, and addition of aniline produces a red color. Pentosans are present in gummy carbohydrates, in bran of wheat seed, and in woods. 

Clean five test tubes by adding a few milliliters of 10% sodium hydroxide to each and heating them in a water bath and then empty and rinse with distilled water. In each tube place one micro drop of a 0.1 M solution of a sugar or of n-butyralde-hyde and 1 ml. of the test solution. Let the reaction proceed first at room temperature and note the order of reactivity, as judged both from the color and by the time of first appearance of silver. After a few minutes put the tubes in the heating bath. The test shows the order of reactivity to be fructose > glucose > lactose > maltose > n-butyraldehyde. 

Honey is produced by honeybees from the flower nectar of plants. Fresh honey is a clear, very aromatic, dark-amber-colored liquid. It is very sticky and hygroscopic, with a density of about 1.40 g/cm3. Honey is an oversaturated solution of glucose and fructose, easy crystallizing. After crystallization its color is brighter. It is a very stable product. At a temperature of 8-10°C and a humidity of 65-75% it may be stored for many years. Honey is a high-caloric food easy assimilated by the human organism. 

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