• Yu.F. Sniezhkin Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine
  • N.О. Dabizha Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine
  • N.S. Malashchuk Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine
Keywords: aromatic raw materials, drying, adsorption, heat pump, energy efficiency, specific energy consumption.


The world market development of plant products demonstrates growing demand for medicinal and aromatic raw materials that are widely used in pharmaceutical, perfume and cosmetic products, food production, etc. An important step in post harvesting storage of medicinal and aromatic plants is drying, which prevents spoilage of raw materials and increases the shelf life of the product. However, heat-sensitive plant components, such as biologically active compounds and essential oils are lost during drying at elevated temperatures. That leads to changes in the aroma, taste and color of dried herbs.

The purpose of the article is studies of dehydration processes of medicinal and aromatic plants to determine energy-efficient drying modes that ensure maximum preservation of biologically active compounds and essential oils.

The temperature of the drying agent plays the most important role in preserving of heat-sensitive components in dried herbs. The analysis of experimental data of temperature effect on content of essential oils showed that drying temperature of aromatic plants should not exceed the maximum allowable temperature of 35-40 °С. The effect of temperature, speed and moisture content of the drying agent on the kinetics of dehydration of peppermint herb has been studied. The experiments were carried out at the drying agent temperature in the range of 30-50 °С, its velocity – 1-2 m/s, moisture content of drying air – 6-14 g/kg d.a.

Significant dependence of drying process duration on heat-humidity parameters of atmospheric air was revealed. To create controlled drying conditions, it is proposed to dehydrate aromatic plants in dryers with a closed circulation circuit using a heat pump.

Energy-efficient drying modes for medicinal and aromatic plants with a variable degree dehumidification of drying agent have been developed, in which the temperature of the material does not exceed the maximum allowable, and aroma losses do not exceed 20-25% of the raw material. The use of a heat pump allows to reduce the specific energy consumption for drying in 2…3 times


1. FAO. Trade in Medicinal Plants [Electronic resource]. Food and Agriculture Organization of the United Nations. – Available at: – Last access – 2014.
2. Pavliuk R.Yu, Poharskaia V.V., Yanytskyi V.V. [Commodity science and innovative technologies of processing of medicinal and technical vegetable raw materials.], [Kharkiv: KhSUFT], 2013. 429 p. (in Rus.)
3. Chakraborty R., Tilottama D. Drying Protocols for Traditional Medicinal Herbs: A Critical Review // International Journal of Engineering Technology, Management and Applied Sciences. 2016. V. 4, I. 4 – P. 312-319.
4. Thamkaew G., Sjöholm I., Galindo F.G. A review of drying methods for improving the quality of dried herbs // Critical Reviews in Food Science and Nutrition. 2021. V. 61, I.11 –P. 1763-1786.
5. Nayak P., Kumar T., Gupta A.K., Joshi N.U. Peppermint a medicinal herb and treasure of health // Journal of Pharmacognosy and Phytochemistry.– 2020. P.1519-1528.
6. Blanco M.C.S.G., Ming L.C., Marques M.O.M., Bovi O.A. Drying temperature effects in peppermint essential oil content and composition // Acta Horticulturae. 2000. V. 569. P. 95-98.
7. Sniezhkin Yu.F., Petrova Zh.O, Ilienko O.O., Loveiko V.O. [Drying of mint on convective dryers]. [Food industry], 2010. V. 9. P. 168-17. (in Ukr.)
8. Karami H., Rasekh M., Darvishi Y., Khaledi R. Effect of Drying Temperature and Air Velocity on the Essential Oil Content of Mentha aquatica L. // Journal of Essential Oil Bearing Plants. 2017. V. 20, I. 4 – P. 1131-1136.
9. Shapar R.A. [Energy-saving technology for the production of dried products from plant materials]. [Scientific Proceedings of ONAFT]. 2008. S.34. V. 2. P. 84-87. (in Rus.)
10. Kovalov V.M., Pavlii O.I., Isakova T.I. [Pharmacognosy with the basics of plant biochemisry],
[Kharkiv: «Prapor» NFAU], 2000, 704 p. (in Ukr.)
11. Sniezhkin Yu.F., Shapar R.O. [Heat-mass exchange technologies for pectin-containing raw materials processing], [Sik Hrup Ukraine], 2018. 228 p. ISBN 978–617–7457–69–4 (in Ukr.)
12. Dabizha N.O. Energy-efficient drying technology of thermolabile materials with using heat pumps]. [Scientific Proceedings of ONAFT], 2011. S. 39. V. 2. P. 341-345. (in Rus.)
13. Snezhkin Yu.F., Chalaev D.M., Shavrin V.S., Shapar R.О., Khavin О.О., Dabizha N.O. [Heat pump application in drying]. [Industrial heat engineering], 2006. V. 28. № 2. P. 106–110. (in Ukr.)
14. Snezhkin Yu.F., Chalaev D.M., Dabizha N.O. [Analysis of energy performance of heat pump
drying]. [Industrial heat engineering], 2017. V. 39. № 3. С. 39–44. (in Ukr.)
15. Snezhkin Yu.F., Chalaev D.M., Shavrin V.S., Dabizha N.O., Gatilov К.O. [Efficiency of using heat pumps in convective drying processes]. [Scientific Proceedings of ONAFT], 2007. S. 30. V.1. P. 185–189. (in Rus.)

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How to Cite
Sniezhkin, Y., Dabizha, N., & Malashchuk, N. (2021). ENERGY RESOURCE SAVING TECHNOLOGIES OF DEHYDRATION OF MEDICINAL AND AROMATIC PLANTS. Thermophysics and Thermal Power Engineering, 43(4), 7-16.
Heat and Mass Transfer Processes and Equipment, Theory and Practice of Drying