Heat and combined pressure-temperature degradation of chlorophyll in broccoli juice have been
studied on a kinetic basis. A treatment at 100 °C and atmospheric pressure during 37 min resulted
in a 90% decrease in total chlorophyll content of broccoli juice. An extreme pressure stability of
both chlorophylls a and b at room temperature was observed. Significant reductions in chlorophyll
content were noticed only when pressure was combined with temperatures exceeding 50 °C.
Chlorophyll degradation reactions at atmospheric as well as at elevated pressures could be adequately
described by assuming a first-order decay. Chlorophyll a degradation occurred more rapidly as
compared to chlorophyll b degradation under all pressure-temperature combinations tested
(1-800 MPa/50-120 °C). Degradation rates increased with temperature according to the Arrhenius
law at all pressures tested.