Why sucrose is not a reducing sugar is as follows:

I. Briefly

Sucrose molecule of glucose with an aldehyde group, and fructose with a ketone group. Although both groups can be oxidized under certain conditions, because sucrose is composed of two sugar molecules, when they are combined, the aldehyde group and the ketone group cancel each other out so that sucrose is no longer reductive. Therefore, sucrose itself is not a reducing sugar.

Two, sucrose

1, sucrose, the main ingredient of table sugar, is a kind of disaccharide, by a molecule of glucose hemiacetal hydroxyl and a molecule of fructose hemiacetal hydroxyl condensed with each other and dehydrated. Sucrose has a sweet taste, odorless, soluble in water and glycerol, slightly soluble in alcohol. There is a spin, but there is no spin effect.

2, sucrose is almost universally found in the leaves, flowers, stems, seeds and fruits of the plant kingdom. It is particularly abundant in sugar cane, sugar beet and maple sap. Sucrose sweet taste, is an important food and sweet flavoring, there are white granulated sugar, granulated sugar, sugar, crystal sugar, crude sugar (yellow sugar) and other sucrose products.

Three, reducing sugar

1, reducing sugar is a sugar with reducing properties. In the sugar, molecules containing free aldehyde or ketone group of monosaccharides and disaccharides containing free aldehyde group have reducing properties. The main reducing sugars are glucose, fructose, galactose, lactose and maltose. Ferring's reagent and Benedict's reagent (Ban's reagent) prepared from citric acid, copper sulfate and sodium hydroxide.

2, often with aldose and ketose in a water bath under the condition of heat reaction produces cuprous oxide brick red precipitate, that is, the reagent itself is reduced, so where the reagent can be reacted with the above mentioned sugar is called reducing sugar (reducing sugar), where the reagent can not be reacted with the above mentioned sugar is called non-reducing sugar (non-reducing sugar), saccharose can not occur. Glycosides cannot undergo the above reaction.

3, glucose molecules contain free aldehyde group, fructose molecules contain free ketone group, lactose and maltose molecules contain free aldehyde group, so they are reducing sugar.