Search results
Results From The WOW.Com Content Network
Sucrose and trehalose are examples of non-reducing disaccharides because their glycosidic bond is between their respective hemiacetal carbon atoms. The reduced chemical reactivity of the non-reducing sugars, in comparison to reducing sugars, may be an advantage where stability in storage is important. [5] [6]
Some sugars, such as sucrose, do not react with any of the reducing-sugar test solutions. However, a non-reducing sugar can be hydrolyzed using dilute hydrochloric acid. After hydrolysis and neutralization of the acid, the product may be a reducing sugar that gives normal reactions with the test solutions.
Hydrolysis of (1→4)-α-D-glucosidic linkages in polysaccharides so as to remove successive maltose units from the non-reducing ends of the chains. This enzyme acts on starch, glycogen and related polysaccharides and oligosaccharides producing beta-maltose by an inversion.
Working from the non-reducing end, β-amylase catalyzes the hydrolysis of the second α-1,4 glycosidic bond, cleaving off two glucose units at a time. During the ripening of fruit, β-amylase breaks starch into maltose, resulting in the sweet flavor of ripe fruit. They belong to glycoside hydrolase family 14.
In these methods, multiple sugars are added to the reaction mixture. One of the sugars is armed as the glycosyl donor, and reacts quickly with a glycosyl acceptor. The non-reducing sugar then acts as a glycosyl acceptor as a protecting group that is easily lost in solution reveals a free hydroxyl group.
The resulting mixture of fructose and glucose is called inverted sugar syrup. Related to invertases are sucrases. Invertases and sucrases hydrolyze sucrose to give the same mixture of glucose and fructose. Invertase is a glycoprotein that hydrolyses (cleaves) the non-reducing terminal β-fructofuranoside residues.
Sucrose (table sugar) contains two sugars (fructose and glucose) joined by their glycosidic bond in such a way as to prevent the glucose undergoing isomerization to an aldehyde, or fructose to alpha-hydroxy-ketone form. Sucrose is thus a non-reducing sugar which does not react with Benedict's reagent.
Trehalose is a nonreducing sugar formed from two glucose units joined by a 1–1 alpha bond, giving it the name α-D-gluco pyranosyl-(1→1)-α-D-gluco pyranoside. The bonding makes trehalose very resistant to acid hydrolysis, and therefore is stable in solution