Chapter 2. Chemistry of Anthocyanins

In this chapter, the current state of knowledge regarding anthocyanin chemistry and the corresponding reversible multistate system of the chemical species is presented. Mathematical equations to account for the kinetics and thermodynamics of the multistate system of anthocyanins are presented in a simple form to allow their use by non-specialists. The calculation of all rate and equilibrium constants of malvidin-3-glucoside in diluted solutions has been carried out to illustrate the use of these expressions. The irreversible reactivity of anthocyanins in foodstuffs, particularly in wine, leading to pyranoanthocyanins of the first and second generation is discussed. The use of the relative energy level diagrams of the multistate species together with their pH-dependent mole fraction distribution is reported and their usefulness emphasized. Using the morning glory flower as an example, the expression of its blue colour is rationalized by considering the thermodynamics and kinetics of the multistate system.