Approaches to understanding the contribution of anthocyanins to the antioxidant capacity of pasteurized pomegranate juices

Abstract

Influence of processing and storage conditions on anthocyanin stability and antioxidant activity of clarified and cloudy juices from arils of the 'Mollar' pomegranate variety was studied. Clarification process reduced the content of total monomeric and individual anthocyanins, and increased the antioxidant activity of pomegranate juice. Thermal treatments (65 and 90 °C for 30 or 5 s) decreased the percentage of polymeric anthocyanin form, increasing on the contrary the monomeric one. In any case, storage temperature was the main factor affecting all the parameters tested. Cyanidin 3-O-glucoside (Cy3G) was more instable than delphinidin 3,5-di (Dp3,5dG) and cyaniding 3,5-diglucosides (Cy3,5dG). A linear relationship was observed between oxygen radical absorbance capacity (ORAC) and total monomeric anthocyanins, suggesting that they contributed strongly to the antioxidant capacity. Results presented in this study show that hurdle technology (heating plus refrigeration) may help to reduce anthocyanin degradation in pasteurized pomegranate juice, avoiding a dramatic impact on its colour and preserving the beneficial effects of this specific bioactive compounds on human health.

Keywords: Anthocyanins; Antioxidant capacity; Pomegranate juice; Thermal pasteurization; Total phenolic compounds.