Does preservation modify the essential oil content and chemical composition of leaf celery (Apium graveolens L. var. secalinum Alef.)?

Preservation of spice plants usually leads to changes in the structure and content of biologically active substances. The present study determined the effect of lyophilization and convection drying on the content and chemical composition of the essential oil from leaves of two leaf celery cultivars. Compared to lyophilization, convection drying allows a larger amount of essential oil to be retained in leaves of leaf celery (respectively by 0.48 and 0.21%). The oil obtained from the material preserved using the convection method had higher amount of limonene, γ-terpinene, (Z)-β-ocimene and β-selinene than that extracted from the lyophilized material, whereas the essential oil from freeze-dried celery had more myrcene and 9H-purin-6-ol than oil from convection-dried celery.