Supercritical Fluid CO2 Extraction of Essential Oil from Spearmint Leaves Dried by Vacuum Drying with a Desiccant


Tokpayev R. Ibraimov Z. Tamina K. Bukenov B. Zhaksybay B. Abdullanova A. Chshendrygina Y. Kishibayev K. Fiori L.
January 2026Multidisciplinary Digital Publishing Institute (MDPI)

Foods
2026#15Issue 2

The essential oil (EO) of Mentha spicata L. (spearmint) exhibits pronounced biological activity, making it valuable for applications in agrochemistry as an insecticidal agent, in perfumery and cosmetics, and as a natural preservative in the food industry. However, maintaining the integrity and yield of EO during post-harvest processing and extraction remains a key technological challenge. This study aimed to enhance the vacuum-drying (VD) process of spearmint using calcium chloride as a desiccant and to optimize the conditions of supercritical CO2 extraction (SC-CO2), including EO separation and the evaluation of its solubility under dynamic extraction conditions. The incorporation of calcium chloride into the VD process reduced drying duration by 21.1% and processing costs by 31.0%, while increasing EO yield by 11%. A decrease in separator pressure from 70 to 10 bar during SC-CO2 extraction resulted in nearly a threefold increase in EO yield by minimizing the loss of volatile constituents. The solubility of spearmint EO in supercritical CO2 was successfully described by the Chrastil model and correlated with carvone solubility. The maximum total phenolic content (72.3 ± 2.2 mg gallic acid equivalent per gram) was observed at a CO2 density of 353.91 kg/m3. The solubility of EO was studied directly using the plant matrix under dynamic conditions.

carvone , desiccant , essential oil , spearmint , supercritical CO2 extraction , vacuum drying

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Center of Physical and Chemical Methods of Research and Analysis, al-Farabi Kazakh National University, 96A, Tole bi, Almaty, 050012, Kazakhstan
Department of Civil Environmental and Mechanical Engineering, University of Trento, via Mesiano 77, Trento, 38123, Italy

Center of Physical and Chemical Methods of Research and Analysis
Department of Civil Environmental and Mechanical Engineering

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