Anthocyanin degradation kinetics during thermal and high pressure treatments of raspberries Original Research Article

The effect of combined high temperature and high pressure on the degradation of the four main cyanidin-3-glycosides in raspberries was investigated. Anthocyanin degradation accelerated with increasing temperature as well as with increasing pressure, revealing a synergistic effect of both process variables. Degradation rate constants were estimated using a first order kinetic model. Temperature and pressure dependence of the degradation rate constants were expressed as activation energies and activation volumes according to Arrhenius and Eyring equations, respectively. In search of statistical differences between the Ea–kref- and Va–kref-parameters estimated simultaneously, 90% joint confidence regions were constructed. A combined Arrhenius–Eyring model was found suitable to describe the combined temperature–pressure dependence of the degradation rate constants. Cyanidin-3-glucorutinoside showed the slowest degradation in comparison to the other cyanidins. Cyanidin-3-rutinoside experienced the smallest effect of temperature and the strongest effect of pressure compared to the others.