Glucose having( i) configuration about C1 is the α-glucose and having( ii) configuration about C1 is β-glucose.
The carbon C1 is known as anomeric carbon and these compounds are called anomers. Both the forms are optically active. ex-D-glucosehas specific rotation + 111.5 ° and β-D-glucose has specific rotation + 19.5 °.
Mutarotation
When either of the two forms of glucose is dissolved in water, there is a spontaneous change in specific rotation till the equilibrium value of + 52.5 °. This is known as mutarotation.
Properties of glucose
Glucose has one aldehyde group, one primary hydroxyl(-CH2OH) and four secondary hydroxyl(-CHOH) groups and gives the following reactions:
These reactions confirm the presence of a carbonyl group in glucose.