Sucrose is not a reducing sugar.

Reducing sugars refer to sugars with reducing properties. Among sugars, monosaccharides containing free aldehyde or ketone groups and disaccharides containing free aldehyde groups are reducing. Reducing sugars mainly include glucose, fructose, galactose, lactose, maltose, etc.

Sucrose is the main component of table sugar and a type of disaccharide. It is formed by the condensation and dehydration of the hemiacetal hydroxyl group of one molecule of glucose and the hemiacetal hydroxyl group of one molecule of fructose. Sucrose is sweet, odorless, easily soluble in water and glycerin, and slightly soluble in alcohol. There is optical activity, but no variable optical rotation. Sucrose is almost universally found in leaves, flowers, stems, seeds and fruits in the plant kingdom.

It is particularly abundant in sugar cane, sugar beet and maple sap. Sucrose has a sweet taste and is an important food and sweet condiment. It is divided into white sugar, brown sugar, soft white sugar, rock sugar, and coarse sugar (brown sugar).

Chemical properties

Sucrose and sucrose solutions will produce various chemical reactions under the action of heat, acid, alkali, yeast, etc. The result of the reaction not only directly causes the loss of sucrose, but also produces some substances harmful to sugar production.

When crystallized sucrose is heated to 160°C, it will thermally decompose and melt into a thick and transparent liquid, and then recrystallize when cooled. When the heating time is extended, sucrose is decomposed into glucose and fructose. At higher temperatures of 190-220°C, sucrose dehydrates and condenses into caramel. Further heating of caramel produces products such as carbon dioxide, carbon monoxide, acetic acid and acetone.

Under humid conditions, sucrose decomposes at 100°C, releasing water and turning black. When the sucrose solution is heated and boiled under normal pressure for a long time, the dissolved sucrose will slowly decompose into equal amounts of glucose and fructose, that is, conversion will occur.

If the sucrose solution is heated to above 108°C, it will hydrolyze rapidly. The greater the concentration of the sugar solution, the more significant the hydrolysis will be. The metal material used in the boiling container also affects the sucrose conversion rate. For example: the conversion effect of sucrose solution in copperware is much greater than that in silverware, and glass containers have almost no effect.

Reference for the above content: Baidu Encyclopedia-Reducing Sugar, Baidu Encyclopedia-Sucrose