Effect of Drying Temperature on Ascorbic Acid Degradation in Cornelian Cherry Fruit (Cornus mas L.): Kinetics and Thermodynamics

In this study, the effect of drying temperature on the degradation of ascorbic acid in cornelian cherry fruit was investigated. Cornelian cherry fruits were dried as single layer in a convective dryer at different air temperatures (50, 60, and 70°C) and 1 m s-1 constant air velocity. Increasing drying temperature increased ascorbic acid degradation. As the temperature increased from 50°C to 70°C, degradation of ascorbic acid increased from 42±0.59% to 49±0.73%. The degradation kinetics of ascorbic acid was investigated according to the zero-order, first-order, and Weibull model. It was observed that the best fitting model for ascorbic acid degradation kinetics was the first order kinetic model. Kinetic parameters such as D, t1/2, and Q10 were calculated using the rate constant of the first-order model. The increased temperature increased the value of degradation and decreased half-life time. The value of Q10 (50°C-60°C) was greater than value of Q10 (60°C-70°C). Thermodynamic results indicated that the degradation of ascorbic acid in cornelian cherry was non-spontaneous, endothermic and irreversible.