Properties
Some of the important physico-chemical characteristics of riboflavin are as follows:
a) Riboflavin forms needle shaped orange crystals.
b) It is sparingly soluble in water and ethanol but its solubility in water is much less than thiamin.
c) Aqueous solution of vitamin B2 emits a yellow-green fluorescence. To see this for yourself, empty the contents of a multivitamin capsule into a glass of water. Stir and observe the yellow-green fluorescence. Isn't it amazing.
d) Though the compound is stable to boiling in acid medium, it is readily destroyed by heat in an alkaline medium. This becomes an important consideration during cooking procedure.
e) Riboflavin is sensitive to light and is destroyed if exposed to light for some time. Milk, which is rich in riboflavin, should not be exposed to sunlight for long. So next time when your milk man leaves the milk packet outside, surely you know what to do.