To obtain essential oil from lavender flowers, water or steam heats the material so that oil moves out of the plant tissue and can be collected. Recovering oil that remains inside the flowers takes time. Could more pathways for oil release be created before distillation?
A study published in 2026 by Dmitry Khudyakov and colleagues addressed this question using cold plasma. It investigated whether recovery could be accelerated and distillation energy reduced without substantially compromising the composition of lavender essential oil.
- A brief electrical-discharge treatment before distillation
- More oil in the same time, or the same oil in less time
- Could pathways form inside the flowers to help oil move?
- Major constituents were retained, but odor preference was not evaluated
- What does the energy saving cover?
- Uniform treatment remains a challenge for larger factories
- Summary
- References
A brief electrical-discharge treatment before distillation
Plasma is a state in which some of a gas consists of electrically charged particles and related species. This study treated flowers before distillation with cold plasma generated by narrow, filament-like discharges. The term cold does not mean chemically inactive: treatment intensity and duration still need to be controlled.
The material was Lavandula angustifolia flowers harvested in Crimea in July 2025. A 1.5 kg batch was conveyed on a tray, and the discharge assembly moved to treat the entire surface. Residence time in the treatment zone was 120 seconds.
Treated and untreated flowers were then compared using two distillation methods. One immersed the flowers in water and heated them in a 1 L laboratory flask. The other passed steam through the flowers in a 25 L pilot-production unit. Treatment and no-treatment conditions were compared within each distillation method.
Each condition was repeated three times using separate flower samples. The researchers measured oil accumulation over time and examined final yield, chemical composition, and flower-tissue structure.
More oil in the same time, or the same oil in less time
At the same distillation duration, more essential oil was recovered from pretreated flowers. Oil mass as a percentage of flower mass increased from 2.46% to 2.65% with water immersion and from 2.33% to 2.65% with steam distillation. The latter is an increase of 0.32 percentage points, or about 13.7% relative to the original yield.
Separately, the researchers compared the time required to collect the same amount of oil. With steam distillation, the amount that took an average of 240 minutes without pretreatment was reportedly recovered in an average of 95.3 minutes after pretreatment.
How much oil is collected in the same time and how long it takes to collect the same amount are different questions. The study used both perspectives to show that pretreatment changed the progress of recovery. It does not mean that essential-oil production was completed by a 120-second pretreatment alone.
Could pathways form inside the flowers to help oil move?
Electron microscopy revealed depressions and groove-like structures in internal flower tissue after pretreatment. The authors suggest that these may create pathways through tissue barriers that impede oil movement, allowing oil to leave more easily during distillation.
A diffusion model was also fitted to the curves of oil recovery over time. Here, diffusion describes the movement of oil-related compounds from inside the tissue toward the outside. The model-derived coefficient representing ease of movement increased after pretreatment with both distillation methods.
Importantly, the microscopic structural changes and estimates from the recovery curves are consistent with the same explanation. However, the researchers did not directly measure retained oil and readily extractable oil separately to establish how much was converted from one to the other. The model also simplifies the shape and thickness of flower fragments.
Major constituents were retained, but odor preference was not evaluated
Increasing recovery would not necessarily make an ingredient useful for perfumery if its desired constituents changed substantially. The researchers therefore analyzed the oil’s volatile compounds by GC–MS.
Linalool and linalyl acetate were the principal constituents with and without pretreatment. Their combined peak-area proportion increased from 65.9% to 68.2% with water immersion and from 63.49% to 68.11% with steam distillation.
These figures describe the proportions of those two compounds among detected constituents. They do not show a corresponding increase in odor intensity or establish oil purity at those same percentages. Other constituents also differed between distillation methods, so the result does not mean that the entire composition remained identical.
The authors conclude that recovery improved while the major-component profile was retained. However, there was no blinded sensory comparison. These chemical analyses cannot establish whether the oils smell the same, are preferred, or are safe for use on skin.
Linalool, introduced here as a major lavender constituent, is also abundant in the essential oil of coriander seeds, a culinary spice. It may be surprising that a floral scent and a kitchen spice share a constituent.
Coriander here means the dried seeds, not the leafy herb used as a garnish. Even when plants contain a compound with the same name, differences in its proportion and its combination with other compounds can make their overall odors seem very different.
What does the energy saving cover?
For steam distillation, the energy required to obtain 1 mL of oil was calculated to decrease from 0.35 kWh without pretreatment to 0.14 kWh with pretreatment. The calculation included the energy used for the electrical-discharge pretreatment.
Under these equipment conditions, the benefit of reducing heating time outweighed the energy needed for pretreatment. However, this was not a whole-system environmental assessment including cultivation, transport, and equipment manufacture. Nor did it demonstrate how many years a factory would need to recoup equipment costs.
Uniform treatment remains a challenge for larger factories
The authors emphasize that flowers can be pretreated while being conveyed. Shorter waiting times per distillation run could increase the amount of flowers processed in essential-oil factories during the concentrated harvest season.
However, the trial used material from one origin and harvest period. Further testing is needed to establish whether flowers in deeper layers can be treated uniformly, how conveying speed and treatment time should be adjusted, and whether other cultivars give similar results.
Stronger treatment is not necessarily better. The authors note that excessive plasma treatment could cause losses of volatile constituents or changes such as oxidation. Finding conditions that balance easier extraction with constituent retention is central to practical implementation.
The study received Russian Science Foundation funding. The authors declared no conflicts of interest and stated that the funder had no role in study design, analysis, writing, or the decision to publish.
Summary
In this experiment, cold-plasma pretreatment enabled faster and greater essential-oil recovery from lavender flowers. Changes in tissue pathways and the model of the recovery curves support the explanation that oil moved more easily from inside the tissue to the outside.
The potential to reduce distillation time and energy while retaining major chemical constituents matters during the harvest season, when raw materials arrive in concentrated volumes. Evaluating the actual odor and verifying uniform treatment at a larger scale are the next steps in developing this production technology.
References
Khudyakov, D., Sherstyukov, A., & Shorstkii, I. (2026). Cold Plasma-Assisted Lavender Essential-Oil Pilot Production: Impact on Oil Yield, Isolation Kinetics and Chemical Parameters. AgriEngineering, 8(8), 300. DOI: 10.3390/agriengineering8080300 / Full text. Original article license: CC BY.
For the sidebar on coriander seed oil: Wahba, H. E., Abd Rabbu, H. S., & Ibrahim, M. E.(2020). Evaluation of essential oil isolated from dry coriander seeds and recycling of the plant waste under different storage conditions. Bulletin of the National Research Centre, 44, 192. DOI: 10.1186/s42269-020-00448-z / Full text.
