Occurrence Glycogen is the storage form of polysaccharide present in animals (muscle and liver). Glycogen in the liver is catabolised to glucose and transferred via blood stream to the tissue for the energy purpose. Glycogen in the muscle acts as a good source of energy.

The basic unit of starch is glucose. It is composed of two units, namely amylase (15%–35%) and amylopectin (65%–85%). The structure of amylose looks like a long helically coiled unbranched chain of glucose molecules connected by α(1 → 4) linkages. The molecular weight of amylase is between 10,000 and 1,00,000. Amylose gives a deep blue…

Starch Occurrence Starch is a polysaccharide that is largely present in the plant kingdom. The most common sources are cereals, grains, potatoes, carrots, millets, and legumes.

Polysaccharides produce more than twelve molecules of monosaccharide units on hydrolysis. The molecular formula is (C6H10O5)n. Polysaccharides are classified into two types:

Oligosaccharides are carbohydrates that yield two to ten monosaccharide units on hydrolysis. An example is maltotriose. They also serve as parts of blood group antigens.

As sucrose is a reducing sugar, it shows negative results to reducing tests. Sucrose is dextrorotatory (+66.5°) and its hydrolytic products are glucose and fructose. The rotation of fructose is laevorotatory (−92°), whereas that of glucose is dextrorotatory (+52.7°). The resulting product of hydrolysis shows laevorotation. This change from dextrorotation to laevorotation is known as…

It is composed of two molecules of monosaccharides, namely glucose and fructose. As both the functional groups (aldehyde and ketone groups) are involved in the formation of glycosidic linkage, there is no free reducing group. Hence, sucrose is known as a non-reducing sugar. The type of linkage in sucrose is α, β(1 → 2) glycosidic…

Sucrose is distributed in plants, particularly in sugarcane and sugar

Sucrose is distributed in plants, particularly in sugarcane and sugar beet.

It forms characteristic ball-shaped crystals with osazone reaction. The anomeric carbon of glucose is free and hence lactose is considered to be positive for all the reducing tests. Galactose is one of the components of lactose, which hence produces mucic acid on treating with concentrated HNO3.