Disaccharide, reducing

C,2H220ii,2H20. M.p. 9TC. A non-reducing disaccharide, which forms the principal carbohydrate of insect haemolymph. It comprises about 25% of trehala manna, the cocoons of a parasitic beetle. Trehalose also occurs in fungi, e.g. Amanita muscaria, generally replacing sucrose in plants lacking chlorophyll and starch. 

The weights of other monosaccharides and reducing disaccharides which will reduce i ml. of this standard Fehling s solution are galactose, 0 00511 g- fructose. 0 00514 g.. mannose, 0 00431 g. lactose, 0 00678 g. maltose, 0 00807 g. 

Note. Such disaccharides are also known as non-reducing disaccharides. 

Note. Disaccharides with a free hemiacetal group are also known as reducing disaccharides. 

Comparison of Sweetness between Reducing Disaccharides and Monosaccharides" by Paired Comparison Test on Sugar Solutions... 

Taste studies of reducing disaccharides containing a reducing ketose residue have also been conducted (see Table XV). In contrast to the aldoses, results obtained with palatinose (36), maltulose (37), lactulose... 

Lactose, the milk sugar, is a reducing disaccharide consisting of glucose and galactose moieties. The estimated annual worldwide availability of lactose as a byproduct from cheese manufacture is several million tons [1,2], but only about 400 000 t/a lactose is processed further from cheese whey [3], Non-processed whey is an environmental problem due to its high biochemical and chemical oxygen demand [2], The use of lactose as such is limited by two main factors relatively low solubility of lactose in most solvents and lactose intolerance in human body [1]. 

The non-reducing disaccharide unit of raffinose and gentianose is certainly sucrose, as previously mentioned in the case of melezitose all that can be said with assurance at the present time is that this sugar is 8-[a-T>-glucopyrano8yl2-(f)-T>-fructofuranosyl-a-j)-glucopyranoside. It would indeed be surprising, from biological views, if the now unknown disaccharide component should eventually prove to be other than sucrose,... 

D-glucose-l-phosphate and D-fructose, Hassid, Doudoroff and Barker18 succeeded in crystallizing a non-reducing disaccharide which was indistinguishable from natural sucrose. It was thus that the first laboratory synthesis of sucrose was achieved. 

This non-reducing disaccharide gives a blue-green color with diazouracil, a reaction shown by Raybin39 to be specific for sucrose and other... 

Recently, the use of two successive degradations by Zempl n s method has been applied to 3-(D-glucopyranosyl)-D-glucopyranose for the preparation of a non-reducing disaccharide, l-(D-glucopyranosyl)-D-erythrofuranoside. 

The reaction was applied with success to unprotected reducing disaccharides [92,93]. The use of iron(III) chloride in ethanol-water gave similar results [94] (see footnote 1). 

The chemistry and physicochemical properties of lactose, a reducing disaccharide containing galactose and glucose linked by a / (l-4)-bond, were described in Chapter 2. 

Maltose (1), systematically named 4-O-a-D-glucopyranosyl-D-gluco-pyranose, is a reducing disaccharide. The numbering of the carbon... 

---