Abstract: In this study, pH, brix, total acidity and trans-resveratrol properties of two different grapes (seedless Sultana and Çalkarası), dried at various temperatures and periods (solar and tray dryer), were investigated. The content of trans-resveratrol was detected by using high performance liquid chromatographic (HPLC) method. During tray drying, degradation of trans-resveratrol in seedless Sultana and Çalkarası grape varieties was fitted to a first- order reaction kinetic model. Arrhenius relationship was used in order to describe the temperature dependence of reaction. Activation energies for trans-resveratrol in seedless Sultana and Çalkarası grape varieties between 50 to 65 °C were found to be 4.97 and 1.63 kcal/mol, respectively. In addition, other kinetic parameters such as reaction rate constant (k), quotient indicator (Q10) and half-life (t1/2) values were also determined.
