Red radish anthocyanins are primarily cyanidin 3-sphorioside-5-glucoside and pelargonidin 3-sphorioside-5-glucoside, both di-glycosylated. This di-glycosylation, coupled with acylation on the on the glycosides, contributes to the colour’s stability through intramolecular stacking.
The stacking blocks reactive hydroxyl groups from interacting with environmental stresses. Anthocyanin colourants exhibit a reversible change in molecular structure as the pH of solutions change from acidic to basic. This change in structure is characterized by a shift in hue from red to purple to blue as the pH changes from acidic to basic.
Red radish has above average stability in food and beverage applications as a natural colourant. It is most stable in acidic conditions.