Rapid extraction of essential oils from freshly harvested plant material
A research project of the Ostwestfalen-Lippe University of Applied Sciences, Process Engineering Laboratory.
Plants use essential oils for a wide variety of tasks, which also explains the different compositions of the oils and where they are deposited within a plant. In labiates and composite plants, the essential oil is stored directly on the leaf surface in glandular scales, while other plants often have their essential oil inside the plant. Essential oils have a wide range of applications in the food industry, and there are a number of different processes for their extraction.
Innovative process technology enables rapid steam distillation
The largest part is obtained through steam distillation. In this process, the plant material is usually flown through with water vapour for several hours. Due to the long vapourisation, the energy costs make up a large part of the production costs of essential oils.
In a project already completed by the project leader, it was possible to reduce the steam-distillative extraction of essential oils from dried plants from approx. 3 hours to max. 3 min. The background is the mechanical opening of the glandular scales, which is achieved by an upstream evacuation step. The now exposed oil can be extracted in a few minutes by steam distillation, which results in a more gentle oil extraction and a reduction of process costs. However, the process described can so far only be applied to dried plants from the labiates family, whose glandular scales are much more sensitive than those of freshly harvested plant material.
The aim of this project is to investigate whether and how essential oils can be rapidly extracted from freshly harvested or frozen material and from plant families in which the glandular scales are not located on the leaf surface but further inside the plant. The focus is on the one hand on the experimental parameters that influence the destruction of the glandular scales and on the other hand on the pre-treatment of the plant material (fresh, dried, frozen). In all experiments, the quality of the oil obtained is always in the foreground in addition to purely quantitative investigations.
Ostwestfalen-Lippe University of Applied Sciences, Process Engineering Laboratory
Project leader: Prof. Dr.-Ing. Ulrich Müller
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