The degradation rules of anthocyanins from eggplant peel and antioxidant capacity in fortified model food system during the thermal treatments

A model food system was designed to explore the effects of food status and thermal treatment ways on degradation of crude anthocyanins from eggplant peel, formation of brown/polymeric color and changes of antioxidant capacity . The pathway of anthocyanin degradation was identified. Degradation of anthocyanins followed first-order kinetics and the rate constant value of anthocyanins were 0.24 and 0.38 h −1 for steamed cookies (solid-state) and boiled cookies (paste), respectively, which was lower than that of 0.71 and 0.39 h −1 for steamed liquid and boiled liquid, respectively. And the half-lives were 2.86, 1.79, 0.98 and 1.78 h steamed cookies, boiled cookies, steamed liquid and boiled liquid, respectively. The anthocyanin content was negatively correlated with the production of brown/polymeric color. The increase of brown/polymeric color index follows zero-order kinetics. The k values of brown index were 0.06, 0.10, 0.10 and 0.10 h −1 and the rate constants of polymeric color index were 0.04, 0.06, 0.05 and 0.07 h −1 for steamed and cookies, steamed and boiled liquid, respectively. The antioxidant activities decreased gradually with treatment time. In conclusion, steaming was a better way to retain anthocyanin than boiling for solid state food, while, boiling was preferable for liquid food.