Effect of drying temperature on the oleuropein content of olive (Olea europea L.) leaves

Olive leaves were dried between 25°C and 150°C or were freeze-dried, the effects of drying temperature on oleuropein contents of olive (Olea europea L.) leaves were estimated. A specific drying temperature region from 65 to 80°C was revealed a declining region of oleuropein contents in the leaves. When olive leaves were treated with boiling water, the oleuropein contents were restored. Enzyme activities might be related to this declining and inactivated with boiling water.