Anthocyanins degradation during storage of Hibiscus sabdariffa extract and evolution of its degradation products.

Degradation parameters of two main anthocyanins from roselle extract ( Hibiscus sabdariffa L.) stored at different temperatures (4–37 °C) over 60 days were determined. Anthocyanins and some of their degradation products were monitored and quantified using HPLC–MS and DAD. Degradation of anthocyanins followed first-order kinetics and reaction rate constants (k values), which were obtained by non-linear regression, showed that the degradation rate of delphinidin 3-O-sambubioside was higher than that of cyanidin 3-O-sambubioside with k values of 9.2·10 −7 s −1 and 8.4·10 −7 s −1 at 37 °C respectively. The temperature dependence of the rate of anthocyanin degradation was modeled by the Arrhenius equation. Degradation of delphinidin 3-O-sambubioside (Ea = 90 kJ mol −1 ) tended to be significantly more sensitive to an increase in temperature than cyanidin 3-O-sambubioside (Ea = 80 kJ mol −1 ). Degradation of these anthocyanins formed scission products (gallic and protocatechuic acids respectively) and was accompanied by an increase in polymeric color index. [ABSTRACT FROM AUTHOR]