Essential oils are aromatic components that exist in different parts of plants. These components are secondary metabolites of aromatic plants. Not only environment factors but also drying temperature effect on this component seriously.
The aim of this research:
1) Does harvested plant need to dry before extraction of essential oil?
2) Does speed of extraction of essential oil differ in dry and fresh parts of plant?
3) Do components of essential oil change in hydrodistillation process from fresh and dry parts of plants?
In this research quantity and quality variation of essential oils on fresh and dry part of four genuses: Anethum graveolens L., Thymus vulgaris L., Mentha piperita L. and Artemisia dracunculus L. were studied.
This research in done at pharmacognosy department of Institute of Medicinal Plants. Essential oil analysis with GC/Mass set. Results showed that:
1- essential oil percentage and constituent in dried tarragon at 35oc temperature was not significant variation with fresh tarragon:
2- Dried Thyme at 35oc temperature reduced essential oil percentage.
3- Results for Peppermint were similar to Thymus.
Studies showed harvesting and drying of plant for 24 hours on field, haven’t any effects on essence percentage and constituents and similar to fresh palnt.
4- The best time for harvesting of dill was green fruit stage of plant and after of this stage the essence percentage was reduced seriously.