Mutarotation

In stereochemistry, mutarotation is the change in optical rotation of a chiral material due to a change in equilibrium between the two constituent anomers (i.e. the interconversion of their respective stereocenters). Cyclic sugars show mutarotation as α and β anomeric forms interconvert. The optical rotation of the solution depends on the optical rotation of each anomer and their ratio in the solution.

Mutarotation was discovered by French chemist Augustin-Pierre Dubrunfaut in 1844, when he noticed that the specific rotation of aqueous sugar solution changes with time.