Degradation kinetics of anthocyanins in blackberry juice and concentrate

Thermal and storage stabilities of anthocyanins in blackberry (Rubus fruticosus L.) juice and concentrate were studied over the temperature range 60-90 degrees C and 5-37 degrees C. Results indicate that the thermal degradation of anthocyanins followed first-order reaction kinetics. The temperature-dependent degradation was adequately modeled on the Arrhenius equation. The activation energy value for the degradation of blackberry anthocyanins during heating was 58.95 kJ/mol for the 8.90 degrees Brix blackberry juice. During storage, antocyanins in the 65.0 degrees Brix blackberry juice concentrate degraded more rapidly than that in 8.90 degrees Brix blackberry juice, with the activation energies of 65.06 kJ/mol and 75.5 kJ/mol, respectively. (C) 2007 Elsevier Ltd. All rights reserved.