Inactivation of peroxidase, polyphenoloxidase, and lipoxygenase in paprika and chili powder after immediate thermal treatment of the plant material

Residual activities of lipoxygenase (LOX), peroxidase (POD), and polyphenoloxidase (PPO) were determined in paprika and chili powder after immediate thermal treatment of the fresh plant material. Heat treatments comprised water and steam blanching of the integral fruits and pasteurization of the comminuted tissues, respectively. PPO showed the lowest heat stability and was completely inactivated by heating at 80 °C for 10 min. Inactivation of LOX was also largely accomplished by heating at 90 °C for 5 min and at 100 °C for 5 min, whereas up to 3.5% (paprika) and 3.3% (chili) of the initial POD activities were retained even when applying rigorous time-temperature regimes. The results demonstrate that substantial inactivation of deteriorative enzymes was ensured by the recently suggested process, thus facilitating the production of high quality spice powders.