Clove essential oil is a powerful and popular essential oil derived from the dried flower buds of the clove tree. It is widely used in the food, cosmetic, and pharmaceutical industries, as well as in aromatherapy and natural medicine. In this article, we will discuss the various extraction methods of clove essential oil, with a focus on CO2 extraction.
3 Extraction Methods of Clove Essential Oil
The three main methods of extracting clove essential oil are steam distillation, solvent extraction, and CO2 extraction. Each method has its own advantages and disadvantages.
Steam distillation is the traditional method of extracting essential oils from plant materials. In this method, steam is passed through the clove buds, causing the oil-containing glands to burst and release the essential oil. The steam and essential oil are then condensed and separated.
The advantages of steam distillation are that it is a simple and inexpensive method and can produce a high-quality essential oil with a rich and warm aroma. However, the yield of essential oil is relatively low, and the process can take a long time.
Solvent extraction is a method of extracting essential oils using organic solvents such as hexane, ethanol, or acetone. The clove buds are first treated with the solvent, which extracts the essential oil. The solvent and essential oil are then separated, and the solvent is evaporated to obtain the essential oil.
The advantages of solvent extraction are that it can produce a high yield of essential oil and is a relatively fast process. However, the solvent residue may leave behind toxic substances and affect the quality of the essential oil.
CO2 extraction is a modern and advanced method of extracting essential oils that uses supercritical carbon dioxide as a solvent. In this method, the clove buds are placed in a high-pressure chamber with carbon dioxide. The carbon dioxide becomes supercritical, which means it has the properties of both a gas and a liquid, and can dissolve the essential oil. The essential oil is then separated from the carbon dioxide by reducing the pressure.
The advantages of CO2 extraction are that it is a safe and eco-friendly method that can produce a high-quality essential oil with a high yield. Additionally, it can extract both the volatile and non-volatile components of the clove buds, which can provide a more complete and complex aroma and flavor profile.
CO2 Extraction of Clove Essential Oil
The CO2 extraction of clove essential oil is a complex process that requires careful control of the parameters, including pressure, temperature, and time. The optimal extraction conditions may vary depending on the equipment and the type of clove buds used.
In a study by Wang et al. (2019), the optimal conditions for CO2 extraction of clove essential oil were found to be a pressure of 30 MPa, a temperature of 40°C, and an extraction time of 120 min. Under these conditions, the yield of clove essential oil was 10.56%.
Effects of CO2 Extraction Parameters on the Yield of Clove Essential Oil
|Extraction Time (min)
|Yield of Clove Essential Oil (%)
In addition to the optimal conditions, the quality of the clove essential oil obtained by CO2 extraction can also be affected by the freshness, maturity, and origin of the clove buds. It is important to select high-quality raw materials and carefully control the process to ensure the purity and stability of the essential oil.
Benefits and Applications of Clove Essential Oil
- Relieves pain and inflammation
- Stimulates circulation and metabolism
- Enhances respiratory function and relieves coughs and colds
- Boosts immune system and fights infections
- Improves dental health and freshens breath
- Used in aromatherapy, massage therapy, and the food and beverage industry
It is the volatile oil obtained by distilling the dried flower buds (syringa) of the Myrtle family plant clove (in ancient times, it was mostly the oil extracted from the mother clove). It is light yellow or colorless and is a clear oily substance with the special aroma of cloves. When clove oil is left in the air or stored for a long time, it will gradually thicken and become yellowish in color. Insoluble in water, easily soluble in alcohol, ether or glacial acetic acid.
Light Golden Yellow
Clove oil is antiseptic and found to be good for throat, arthritis, rheumatism, sinus, cataracts and toothaches. It raises the blood pressure and is effective in impotency.
clovebuds, cloves, clove powder
Strength of Aroma
Medium to Strong
Rosemary, Peppermint, grapefruit, citronella, orange, lemon, rose and other spice based oils.
Clove Bud essential oil has a strong rich spicy scent.
In the 16th and 17th centuries Cloves and nutmeg were among the most valuable in Europe than gold.
Clove Bud essential oil can cause sensitization in some cases and should be used in dilution. It is to be avoided during pregnancy.
- Properties: Clove oil is a light yellow or colorless, clear oily substance, with the special aroma of cloves, sweet and spicy, and hot in nature; when exposed to the air or stored for a long time, it will become thicker and brownish in color.
- Main ingredient: Eugenol
- Content: 85%
- Relative density: 1.030-1.050
- Refraction: 1.530-1.540
Lilac, evergreen tree, up to 10 meters high. The leaves are opposite; the petioles are obvious; the leaves are oblong ovoid or oblong obovate, 5-10cm long, 2.5-5cm wide, apex acuminate or sharp, narrow base and often spread out into a stalk, entire.
- The flowers are fragrant and form a terminal cyme with a flower diameter of about 6mm;
- Calyx is thick, turn purple after green, long tubular, apex 4-lobed, lobes triangular;
- Corolla white, slightly purple, short tube flat, 4-lobed;
- Many stamens, anthers split longitudinally;
- The ovary is inferior, connate with the calyx tube, the style is thick, and the stigma is not obvious.
- The berry is reddish brown, oblong oval, 1-1.5cm long, 5-8mm in diameter, and persistent sepals at the apex.
- The seeds are rectangular.
How to extract clove oil
Supercritical CO2 extraction of clove oil
The cloves were crushed into coarse powder and placed in a CO2 supercritical extraction equipment. According to the process conditions used by Chen Gengfu (2002), the pressure was 10MPa, the temperature was 40°C, and the CO2 flow rate was 22L/h for 4 hours. The pressure was 7.0 MPa and the temperature was 45°C for analysis to obtain clove oil.
Extraction of clove oil by steam distillation
Crush the processed cloves with a small grain grinder. Accurately weigh a certain amount of dry clove powder and place it in a distillation flask, add a certain amount of water in proportion, connect the condenser tube, and start the distillation. After the distillation is completed, transfer the obtained oil-water mixture to the separatory funnel and let it stand still. After stratification, the crude clove oil was separated.
Add a certain amount of anhydrous ether to the crude clove oil, separate the water in a separatory funnel, and then treat with anhydrous sodium sulfate to remove the ether in the clove oil under reduced pressure to obtain refined clove oil. The extraction rate of clove oil is 9.94%. The volatile oils are all light yellow oily liquids with the unique fragrance of cloves.
The cloves are crushed, weighed accurately, wrapped in dried filter paper, placed in a triangular flask, a certain amount of organic solvent is added in proportion, sealed, placed in a constant temperature water bath, and placed in a constant temperature for different periods of time, and then taken out Filter paper bag and recover organic solvent to obtain clove oleoresin. Clove oleoresin is more viscous, and the smell is not as strong as that of clove volatile oil.
Supercritical CO2 extraction is a widely used method to extract Pomegranate seed oil. Pomegranate seed oil is derived from the seeds of the Pomegranate fruit (Punica granatum) and is known for its numerous health benefits and applications in the cosmetic and food industries. Here is an overview of the process of supercritical CO2 extraction of Pomegranate seed oil:
- Material Preparation: Pomegranate seeds are carefully collected and dried to remove excess moisture. This helps maintain the quality and integrity of the seeds during the extraction process.
- Supercritical CO2 Extraction Setup: The supercritical CO2 extraction system consists of a high-pressure extraction vessel, a CO2 supply system, a heat exchanger, and a separator. The extraction vessel is designed to withstand the high pressures required for creating the supercritical state of CO2.
- Adjustment of Parameters: The extraction parameters, such as temperature, pressure, and flow rate, are carefully controlled to optimize the extraction process. These parameters are specific to the Pomegranate seeds and the desired composition of the oil.
- Loading the Material: The prepared Pomegranate seeds are loaded into the extraction vessel. The vessel is then sealed, and CO2 is introduced to pressurize the system.
- Extraction: The CO2 is brought to its supercritical state by increasing the temperature and pressure. In this state, CO2 acts as a highly efficient solvent, penetrating the seeds and dissolving the oil components.
- Separation: After the extraction is complete, the mixture of CO2 and dissolved Pomegranate seed oil is directed to the separator. Here, the pressure is reduced, causing the CO2 to revert to its gaseous state, leaving behind the extracted Pomegranate seed oil.
- Collection and Storage: The Pomegranate seed oil is collected and stored in appropriate containers, ensuring proper labeling and storage conditions to preserve its quality.
Supercritical CO2 extraction offers several advantages for extracting Pomegranate seed oil. It allows for the selective extraction of valuable components, such as punicic acid and other bioactive compounds, while minimizing the extraction of undesirable components. The process operates at relatively low temperatures, preserving the delicate nutritional profile of the seeds and preventing thermal degradation of the oil. Additionally, the use of CO2 as the solvent eliminates the need for toxic solvents, making it a safer and more environmentally friendly method.
The extracted Pomegranate seed oil finds applications in various industries. In the cosmetic industry, it is used in skincare products, hair care formulations, and anti-aging products due to its antioxidant properties and potential benefits for skin health. In the food industry, Pomegranate seed oil is utilized as a culinary oil, salad dressing ingredient, or added to beverages for its unique flavor and potential health benefits.
Supercritical CO2 extraction of Pomegranate seed oil provides a reliable and efficient method to obtain high-quality oil with its distinct nutritional profile and potential health benefits. Its application extends to various industries, where the unique properties of Pomegranate seed oil find diverse uses.
Clove essential oil is a highly valued and versatile essential oil with many health benefits and applications. The extraction methods of clove essential oil include steam distillation, solvent extraction, and CO2 extraction. Among them, CO2 extraction is the most advanced and efficient method that can produce a high-quality and complex essential oil. The CO2 extraction of clove essential oil requires careful control of the parameters and selection of high-quality raw materials to ensure the purity and stability of the final product.