Glycosidic bond of sugar unit

Polysaccharides chains are generally formed by a repeated sequence of monomers or oligomers. Few monosaccharides exist in the free state. They generally occur linked by glycosidic bond to one another or to an aglycones.

The term ‘glycosidic bond’ is used for the bond between the anomeric C-atom and the glycosidic O (N-, S,) atom.

While the term ‘glycosidic linkage is used to define a set of all bonds that connects to monosaccharide rings.

It is a bond that links two sugar units together; it is formed between the free carbonyl group of one sugar and a hydroxyl group of another sugar; the orientation (α or β) and position (eg. 1,4) of the link must be specified. The structure of a di-, oligo- or polysaccharide sugar is based on the bonding of two monosaccharides.

In the case of a disaccharide, two monosaccharides are joined with loss of one molecule of water. This joining occurs between two –OH groups, one of each monosaccharide.
Glycosidic bond of sugar unit

Disaccharides sugar

Simple carbohydrates are naturally present as simple sugars in fruits, milk and other foods. Plant carbohydrates also can be refined to produce sugar products such as table sugar or corn syrup.

Two main types of sugars are monosaccharides and disaccharides.

Disaccharides are formed by the elimination of a water and it contain two monosaccharides joined together with a special linkage, called a glycosidic bond.

Several disaccharides are important in foods sucrose or table sugar is the most common and contains glucose and fructose.

Three disaccharides are important in nutrition: maltose, sucrose and lactose.

Sucrose is the most familiar of the three disaccharides and is what people mean when they speak of sugar. When the person eats a food containing sucrose, enzymes in the digestive tract splits the sucrose into its glucoses and fructose components. Because the body can convert fructose to glucose, one molecule of sucrose can ultimately yield two molecules of glucose.

Lactose also in known as milk sugar because it is a found in milk. Lactose is composed of one molecule glucose an one molecules of galactose.

It is the least sweet and least soluble of the sugars.
Disaccharides sugar