Coriander leaves are widely used in cooking
throughout the world. Thermal degradation kinetics of
chlorophyll a, b, and total chlorophyll in coriander leaf
puree was investigated at varying levels of pH (4.5–8.5)
and processing temperature (80–145°C). Coriander puree at
pH 4.5 was processed at 80° to 100°C, whereas that at pH
5.5 to 8.5 was processed at 105° to 145°C. Chlorophyll
degradation followed first-order reaction kinetics. Good
agreement was found between estimated and experimental
chlorophyll retention in all cases (R2>0.80). Activation
energies ranged from 6.57 to 96.00 kJ/mol. Reaction rate
and activation energy data indicated that chlorophylls were
more stable at alkaline pH. Transition state theory was
applied to estimate the enthalpy, entropy, and Gibbs free
energy of activation. Enthalpy of activation (ΔH#) ranged
from 3.46 to 91.99 kJ/mol, whereas entropy of activation
(ΔS#) ranged from −0.265 to −0.047 kJ/(mol K). The
overall free energy change was 107.55 kJ/mol. Results
indicated that, the compensation effect did not exist for
chlorophyll degradation in coriander puree during thermal
processing.