KINETIC OF CHLOROPHYLL DEGRADATION AND COLOR CHANGE IN BITTER GOURD DURING HEAT TREATMENT

Thermal degradation kinetics of chlorophylls and visual green color loss in bitter gourd were investigated at 70, 80, 90 and 100°C. The loss of visual green color, as represented by the change of the ?a value and the ?a/b ratio measured by tristimulus colorimeter, All the degradation of chlorophyll a, chlorophyll b as well as visual green color loss followed a first?order reaction. The rate constants of all parameters increased with increasing temperature and followed the Arrhenius model. The activation energies for chlorophylls a and b were determined as 32.90 ± 2.68 and 49.96 ± 3.86 kJ/mol, while those for ?a value and ?a/b ratio were found as 22.75 ± 1.96 and 53.55 ± 4.08 kJ/mol, respectively