Solar energy‐based extraction of essential oils from cloves, cinnamon, orange, lemon, eucalyptus, and cardamom: A clean energy technology for green extraction

Abstract

Conventional essential oil extraction systems cannot meet the green extraction concepts and sustainable development goals (SDGs). Therefore, there is a need to develop alternative systems based on clean energy. The present study aims to investigate the possibility of essential oil extraction using solar energy without utilizing synthetic solvents. Hence, an eco-friendly solar energy-based extraction system (SEE) was developed to extract essential oils from cloves and cinnamon barks, orange and lemon peels, eucalyptus leaves, and cardamom seeds. Essential oils were assessed in terms of yield, physical properties, and chemical composition using gas chromatography-mass spectrometry assay. Also, the process sustainability was analyzed by the green extraction evaluation approach, and results were compared with those of traditional hydro-distillation (THD). Replacing THD with SEE increased the extraction time by 0.65, 0.80, 0.41, 0.61, 0.39, and 0.45 h for processing clove, cinnamon, orange, lemon, eucalyptus, and cardamom, respectively. The optimum solar radiation for extraction was about 1000 W/m 2 . Also, oxygen compounds (96.45, 79.640, 42.98, and 83.76%) comprised the main proportion in the clove, cinnamon, eucalyptus, and cardamom essential oils, while orange and lemon essential oils had a high presence of terpenes. Furthermore, essential oils obtained by SEE had a similar yield and alcohol solubility to THD. According to green extraction process analysis, solar energy-based extraction was 23-34% greener than THD, depending on the type of plant material. Practical ApplicationsThe innovative solar-based extraction system designed and developed in this research can be used at farms and small factories to obtain essential oils using the zero-energy concept. From the energy consumption viewpoint, this technology can be regarded as "free process" which can reduce production costs. Also, the unique design of the heating section of this new system prevents overheating of the sample, making this new solar-based system suitable for the extraction of thermolabile compounds from plant materials. In this sense, obtaining a high-quality essential oil

Recent advances in the extraction, chemical composition, therapeutic potential, and delivery of cardamom phytochemicals

“…SEE when compared to traditional hydrodistillation, extraction time was increased by 0.45 h with an optimized solar radiation of about 1000 W/m 2 . Further analysis revealed that SEE was 23-34% greener than the traditional hydrodistillation based on plant material type (9).…”

“…Various extraction procedures have been used to obtain phytochemicals, and can be classified as conventional-(e.g., hydrodistillation, steam distillation and Soxhlet extraction) and advance extraction methods (e.g., enzyme-assisted-, instant controlled pressure drop-, microwave-assisted-, pressurized liquid-, solar energy-based-, sub-critical-, supercritical fluid-, and ultrasound-assisted extractions) (2,9,10,(20)(21)(22)(23)(24)(25). Conventional extraction methods have wider applicability in the extraction of phytochemicals due to ease of operation, however, they require more time and huge amount of solvents, and give less extraction yield, thus making up-scaling difficult.…”

“…To date, different extraction techniques including conventional extraction methods (e.g., hydrodistillation and Soxhlet apparatus) and advance procedures (e.g., ultrasound-assisted-, microwaveassisted-, supercritical fluid-, sub-critical-, pressurized liquid-, enzyme-assisted-, instant controlled pressure drop-, and solar energy-based extractions) have been used for the extraction of dietary phytochemicals. Among the various extraction techniques, supercritical fluid extraction (SFE) has the potential advantages of controlled operative conditions (time, temperature and pressure), less sample degradation, accelerated mass transfer, and no further sample clean-up (1,6,9,10).…”

“…Comparative analysis of black and green cardamom: plant part, oil yield (%), extraction method, and extraction solvent. Steam distillation, 2 hydrodistillation, 3 microwave-assisted hydrodistillation,4 simultaneous distillation extraction,5 supercritical fluid extraction,6 solvent extraction,7 microwave-assisted extraction, 8 enzyme-assisted hydrodistillation,9 pressurized liquid extraction, 10 ultrasound-assisted hydrodistillation, 11 controlled pressure-drop,12 solar energy-based extraction.…”

Innovative methods for extraction of essential oils from medicinal plants

“…Essential oils from different plant sources are extracted using a solar distillation system like eucalyptus leaves, peppermint leaves, clove buds, fennel seeds, basil, lavender, cumin, cardamom, orange, lemon, rosemary, citrus, Cymbopogon, etc. (Table 8) (Al-Hilphy et al, 2022;Radwan et al, 2020;Afzal et al, 2017;Yen and Lin, 2017). Antioxidant and antimicrobial activity (Afzal et al, 2017;Schmidt et al, 2009;Mimica-Dukić et al, 2003) Pinus (Roxburghii) α-Pinene (Afzal et al, 2017) Lavandula angustifolia; Lamiaceae (Flowers) Lavender β-Pinene, β-phellandrene, borneol, camphor, linalool, terpineol, linalyl acetate, terpineol-4-ol, cymene and 1,8-cineole Antimicrobial, anti-inflammatory, and antioxidant activity (Radwan et al, 2020;Lakušić et al, 2014;Danh et al, 2012;Wells et al, 2018) Cymbopogon citratus (DC) Stapf..; Poaceae (Leaves)…”