Kinetics of the change in bioactive compounds, antioxidant activity and color of dried cornelian cherry at different temperatures

In this study stability of bioactive compounds, antioxidant activity and visual color of cornelian cherry during convective drying at different temperatures. Cornelian cherries have been dried at 50°, 60° and 70 °C for 36, 13.5 and 6 hours, respectively. The contents of total monomeric anthocyanins, total phenolics, total flavonoids, L-ascorbic acid and antioxidant activity were determined by spectrophotometric methods. Cyanidin-3-galactoside was determined by HPLC. It was determined that total monomeric anthocyanins, L-ascorbic acid and cyanidin-3-galactoside degraded according to a first-order kinetic model during drying of cornelian cherry. The contents of total phenolics and total flavonoids of cornelian cherry were also decreased during drying and this change fitted to a second-order reaction. The losses of bioactive compounds of dried cornelian cherries decreased by increasing temperature except for the loss of cyanidin-3-galactoside. Antioxidant activity and polymeric colour density of dried cornelian cherries increased. It was observed that cyanidin-3-galactoside was the major anthocyanin in cornelian cherry and decreased during drying. The activation energies for the degradation of total monomeric anthocyanins, total phenolics, flavonoids, L-ascorbic acid, cyanidin-3-galactoside were found 13.3, 12.09, 18.81, 11.5 and 17.5 kcal moL-1, respectively. After drying cornelian cherry at different temperatures, visuall color parametres were decreased according to first-order reaction. KEYWORDS: cornelian cherry, total phenolic, total flavonoid, antioxidant activity, cyanidin-3-galactoside, total monomeric anthocyanin, L-ascorbic acid, activation energy, color