Degradation kinetics and antioxidant capacity of anthocyanins in air-impingement jet dried purple potato slices.

We investigated the types, degradation kinetics, and antioxidant capacities of anthocyanins in purple potato slices subjected to air-impingement jet drying (AIJD) at different drying temperatures (50, 65, and 80°C). Petunidin-3-p-coumaroylrutinoside-5-glucoside was the predominant anthocyanin in AIJD-treated purple potato and was positively correlated with antioxidant capacity. Anthocyanin concentration decreased with drying time, and anthocyanin degradation followed first-order reaction kinetics. At high drying temperatures, anthocyanin degradation had higher degradation rates and shorter half-life than at low drying temperatures. Thermodynamic results revealed that the degradation of anthocyanins is a non-spontaneous, endothermic reaction and that the transition state has lower structural freedom than the reactant. AIJD at 65°C contributed to the highest anthocyanin content and antioxidant capacity.