Apple and quince peroxidase activity in response to essential oils application
Enzymatic browning arises by peroxidase in fruits. However, essential oils are recognized as natural antioxidant agents. So in this study, the effect of thyme, coriander and rosemary essential oils were evaluated on the reduction of peroxidase activity in apples (Malus domestica Mill. cv Golden delicious), (M. domestica Mill. cv Red delicious) and quince (Cydonia oblonga Mill. cv. Esfahan). In this study, 50, 75, 100 or 200 μl/100 ml concentrations of pure essential oil were applied in vivo and in vitro. The results revealed the control samples of golden delicious, red delicious and quince had 185, 142.5 and 300 (units/min/g) peroxidase activity, respectively. In vitro 75 μl/100 ml of thyme and in vivo 50 μl/100 ml of thyme and 200 μl/100 ml of rosemary essential oils exerted the highest antioxidant ability (reductions in peroxidase activity by 92%) in the golden delicious. In vitro experiments were focused on the coriander essential oil treatments offering potential antioxidant benefits in the red delicious. Peroxidase activity was affected by in vivo 50 μl/100 ml concentrations of pure rosemary essential oil (reductions in peroxidase activity by 90%) when the enzyme was obtained from quince.
Key words: Peroxidase, essential oil, antioxidant, apple, quince.