Effect of thermal treatment on phenolic compounds from plum (prunus domestica) extracts – A kinetic study

• Impact of thermal treatment on phenolic compounds was investigated.
• Fluorescence spectra of plum extracts suggested the presence of at least four species.
• During heating phenolic compounds degradation followed a biphasic order kinetic model.

The effect of thermal treatment on the degradation of the polyphenolic compounds in plum extract was investigated in the range of 70–110 °C by means of fluorescence spectroscopy and spectrophotometric techniques. The fluorescence results suggested that plum extract represents a multicomponent system with different fluorescence species. The heating of plum extract resulted in structural changes that led to a significant decrease in fluorescence intensity at higher temperature when the solutions were excited at 300 nm, whereas, when excited at 410 nm, significant increase in fluorescence intensity was measured in the temperature range of 70 and 110 °C. Degradation rate constants were estimated using a first order kinetic model. Temperature dependence of the degradation rate constants were expressed according to the Arrhenius model. The total monomeric anthocyanins showed the highest degradation in comparison to other polyphenols, as well as to antioxidant activity.