Use of Weibull distribution for describing kinetics of antioxidant potential changes in fresh-cut watermelon

Abstract

Changes in antioxidant capacity, vitamin C, lycopene and total phenolic compound retention of fresh-cut watermelon stored at selected temperatures (5–20 C) for 14 days storage were accurately described by a Weibull distribution function. The temperature dependency of the Weibull kinetic rate constants was studied through an Arrhenius-type relationship. The degradation kinetic constants of Weibull model increased with temperature. Therefore, initial antioxidant potential of fresh-cut watermelon was best maintained at storage temperature of 5 C for 14 days. The activation energies for lycopene, vitamin C, antioxidant capacity and total phenolic compounds were 56.5 kJ mol 1, 55.9 kJ mol 1, 34.5 kJ mol 1 and 26.9 kJ mol 1, respectively. Thus, a high temperature sensitivity of lycopene, vitamin C and antioxidant capacity related reactions were observed compared to that of total phenolic compounds.

This work was supporting by the Interministerial Commission for Science and Technology (CICYT) of the Ministerio de Educación y Ciencia (Spain) through the Project ALI 2005-05768. Isabel Odriozola- Serrano thanks the Agència de Gestió d’Ajuts Universitaris i de Recerca of the Generalitat de Catalunya (Spain) and the European Social Fund for the pre-doctoral grant.