Disaccharide hydrolysis

In determining the structure of a disaccharide, hydrolysis data estabhsh the identity of the component monosaccharides. However, three questions remain. 

Miller, D., and Crane, R. K., 1961, The digestive function of the epithelium of the small intestine, 11. Localization of disaccharide hydrolysis in the isolated brush border portion of intestinal epithelial cells, Biochim. Biophys. Acta 52 293. ... 

Hydrolysis by acids. Place 15 ml. of starch solution in a boiling-tube, add I ml. of cone. HCl, mix well and place in a boiling water-bath for 20 minutes. Cool and add 2 drops of iodine solution to i ml. of the solution no blue coloration is produced. On the remainder, perform tests for glucose in particular show that glucosazone can be formed. Neutralise the excess of acid before carrying out these tests. (Note that a more concentrated acid is required to hydrolyse starch than to hydrolyse the disaccharides, such as sucrose.)... 

Carbohydrates may be divided into monosaccharides, disaccharides and polysaccharides. The monosaccharides under certain conditions react as polyhydroxy-aldehydes or polyhydroxy-ketones two important representatives are glucose CjHjjO (an aldose) and fructose (laevulose) CgHuO, (a ketose). Upon hydrolysis di- and polysaccharides 3deld ultimately monosaccharides. Common disaccharides are sucrose, lactose and maltose (all of molecular formula C,2H2. 0,), whilst starch, dextrin and cellulose, (CjHjoOj), in which n > 4, are typical polysaccharides. 

Disaccharides are sugars which yield two molecules of monosaccharides upon hydrolysis. The four of greatest practical interest are ... 

Disaccharides, e.g., lactose, which yield galactose upon hydrolysis, will also give the sparingly-soluble mucic acid but in poorer 3deld. This reaction may be employed for the differentiation between certain disaccharides lactose — mucic + saccharic acids sucrose — saccharic acid only maltose — saccharic acid only. 

D (+) Galactose is a constituent of numerous polysaccharides It is best obtained by acid hydrolysis of lactose (milk sugar) a disaccharide of d glucose and d galactose L (—) Galactose also occurs naturally and can be prepared by hydrolysis of flaxseed gum and agar The principal source of d (+) mannose is hydrolysis of the polysaccharide of the ivory nut a large nut like seed obtained from a South American palm... 

Maltose obtained by the hydrolysis of starch and cellobiose by the hydrolysis of cellulose are isomenc disaccharides In both maltose and cellobiose two d glucopyra nose units are joined by a glycosidic bond between C 1 of one unit and C 4 of the other The two are diastereomers differing only m the stereochemistry at the anomeric carbon of the glycoside bond maltose is an a glycoside cellobiose is a (3 glycoside... 

Disaccharide (Sections 25 1 and 25 14) A carbohydrate that yields two monosaccharide units (which may be the same or different) on hydrolysis... 

Sugar is destroyed by pH extremes, and inadequate pH control can cause significant sucrose losses in sugar mills. Sucrose is one of the most acid-labile disaccharides known (27), and its hydrolysis to invert is readily catalyzed by heat and low pH prolonged exposure converts the monosaccharides to hydroxymethyl furfural, which has appHcations for synthesis of glycols, ethers, polymers, and pharmaceuticals (16,30). The molecular mechanism that occurs during acid hydrolysis operates, albeit slowly, as high as pH 8.5 (18). 

Among the various types of sugars marketed, the mass consumption of sucrose far outweighs by volume the consumption of other products. Sucrose, also called table sugar, is a disaccharide which, upon hydrolysis, yields two monosaccharides glucose and fmctose. Various types of sugar vary in sweetness (1). 

For the most part, low molecular weight carbohydrates of commerce are made by depolymerization via enzyme- or acid catalyzed hydrolysis of polysaccharides. Only sucrose and, to a very much lesser extent, lactose, both disaccharides, are commercial low molecular weight carbohydrates not made in this way. 

Disaccharides are carbohydrates that yield two monosaccharide molecules on hydrolysis. Str-ucturally, disaccharides are glycosides in which the alkoxy group attached to the anomeric carbon is derived from a second sugar- molecule. 

Sections Disaccharides are carbohydrates in which two monosaccharides are 25.14-25.15 joined by a glycoside bond. Polysaccharides have many monosaccharide units connected through glycosidic linkages. Complete hydrolysis of disaccharides and polysaccharides cleaves the glycoside bonds, yielding the free monosaccharide components. 

Cellobiose (Section 25.14) A disaccharide in which two glucose units are joined by a (3(1,4) linkage. Cellobiose is obtained by the hydrolysis of cellulose. 

The glycosidic bond to an anomeric carbon can be either a or (3. Maltose, the disaccharide obtained by enzyme-catalyzed hydrolysis of starch, consists of two cv-D-glucopyranose units joined by a 1->4-o-glycoside bond. Cellobiose, the disaccharide obtained by partial hydrolysis of cellulose, consists of two /3-o-glucopyranose units joined by a 1—>4-/3-glycoside bond. 

Trehalose is a nonreducing disaccharide that is hydrolyzed by aqueous acid to yield 2 equivalents of D-glucose. Methylation followed by hydrolysis yields 2 equivalents of 2,3,4,6-tetra-O-methylglucose. How many structures are possible for trehalose ... 

An important metabolic reaction of disaccharides is the reverse of (5). Water, in the presence of H+(aq), reacts with sucrose to give glucose and fructose. This process is called hydrolysis, meaning reaction with water."... 

An important reaction of fats is the reverse of ester formation. They hydrolyze, or react with water, just as disaccharides do. Usually hydrolysis is carried out in aqueous Ca(OH)2, NaOH, or KOH solution. Because of long use in the preparation of soap from fats, the alkaline hydrolysis reaction (6) is called saponification. 

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