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Ethanol, steam, and co2 extraction process of black pepper oil

Black pepper essential oil

Black pepper, a vine, belongs to the Piperaceae family. It is dried and processed from the spherical berries of the Piperaceae plant. Those with a black peel are called black pepper. Its fruity and spicy flavor is one of the earliest and most widely used spices. Medicine is also commonly used as carminative and chronic indigestion medicine. Black pepper is often used as a spice and seasoning in the food industry because its essential oil has good antiseptic and antioxidant effects, and it can also be used as a natural preservative and antioxidant for pickled foods.

Black pepper essential oil is colorless to a light amber clear liquid, with a soft pepper characteristic aroma, a rich, mellow, natural, and fresh flavor, and together with other volatile components, it imparts a fresh and spicy flavor to black pepper. Black pepper essential oil can be used as spice raw materials, pharmaceutical raw materials, etc., and has high medicinal value and edible value.

Main ingredient

Black pepper essential oil contains mainly monoterpenes and sesquiterpenes.
Thirty-seven chemical constituents were isolated and determined from the volatile oil of black pepper, accounting for 99.37% of the total detected amount, including 20 terpenoids, accounting for 29.89% of the total detected amount; 8 sesquiterpenoids, accounting for 29.89% of the total detected amount. 44.62% of the total detected amount; two sesquiterpene oxides accounted for 4.41% of the total detected amount. The most abundant components were carane (12.43%), limonene (8.05%), caryophyllene (31.66%), β-pinene (4.14%), and copaene (4.89%).


Black pepper has an effect on both medicine and food. It is not only an indispensable spice and condiment on people’s tables, but also can be used as a raw material for essence and medicine. Therefore, it has a very wide range of applications in the food, chemical, and pharmaceutical industries. Because of its unique sensory properties and numerous uses, it has a broad consumer market in the world.

3 extraction processes of black pepper essential oil

The popular extraction methods of black pepper essential oil include ethanol extraction, distillation, and CO2 supercritical extraction.

Ethanol extraction

Like all spices, black pepper contains volatile essential oils. However, this black pepper essential oil cannot simply be melted or washed away in the water. After all, oil and water don’t mix. Solvents are required to separate essential oils from plant matter.
Solvent extraction is based on the principle of similar compatibility of substances. Ethanol, butane, and propane are the most commonly used solvents for professional extractors. These solvents can be used to extract essential oils from black pepper berries. However, not all solvents and extraction methods are created equal.
However, not all solvents and extraction methods are created equal. Some, like ethanol and carbon dioxide, are safer for consumers and processors. However, even these two processes can produce very different products.

What is ethanol extraction?

The ethanol extraction method refers to the method of separating and purifying substances using ethanol as a solvent by utilizing the solubility of ethanol. It is widely used in chemical experiments, chemical purification, chemical pharmacy, and the preparation of traditional Chinese medicine.
Simply put, ethanol is alcohol. In ethanol extraction, ethanol is used as a solvent. Unlike other solvents such as butane, ethanol is considered a safe, clean solvent with little risk of toxicity. In addition to solvent-free extraction, ethanol is considered one of the safest solvents in consumer products. While all commercial extracts must be laboratory tested to ensure there are no unsafe levels of residual solvents, ethanol evaporates easily and poses little risk to human health.
As a solvent, ethanol is highly efficient. Alcohols are polar in nature, allowing ethanol to form bonds with water- and fat-soluble plant compounds. Unlike other solvents, ethanol is not so picky about what is extracted from plant material, and specialized equipment allows the extractor to further purify its ethanol concentrate.

Extraction of pepper oleoresin by ethanol method

The ethanol method was used to extract pepper oleoresin, and the optimization conditions were obtained: ethanol volume fraction 85%, raw material particle size 80 mesh, material-liquid ratio 1:10, leaching time 3.5h, leaching temperature 65 ℃ process conditions, black pepper Oleoresin has a maximum extraction rate of 10.32%.

Distillation extraction

Distillation is the main method for extracting essential oils from plants.
Distillation methods can rupture the cell walls of plant cells and release the essence stored in the cells in the state of steam. The vapors of these greases are mixed with water vapor, go into a cooling tube, return to a liquid state, and are finally collected in a larger bottle. Water vapor condenses into water, and essence condenses into essential oils. Essential oils are lighter than water, so they can be easily separated and collected from the aqueous layer.

Most black pepper oil is extracted by steam distillation. A popular method, steam distillation involves forcing pressurized steam through the fruit. The temperature of the hot steam must be high enough to release the essential oils, but not so high that it damages the plants. The steam with the essential oils then passes through a cooling system where the steam condenses into a liquid of essential oils and water. The oil will float to the top because it is lighter than water and can then be separated from the water.

CO2 extraction

CO2 extraction is a modern extraction process for extracting essential oils from plants.
Since CO2 extraction takes place at lower temperatures in so-called “cold separation”, CO2 extraction is rapidly replacing steam distillation as the true botanical properties of plant material are better preserved.

CO2 extraction, also known as “supercritical CO2 extraction,” involves the use of high-pressure carbon dioxide to extract essential oils from plant matter, a method that is faster, more energy-efficient, and better than other extraction methods.

How does CO2 extraction work?

CO2 extraction is similar to steam extraction, with some key differences. Read on to learn about the steps associated with this extraction method:

Fill the tank. The plant matter is placed in a storage tank pumped with high-pressure carbon dioxide.
Towards “supercritical”. When CO2 is sufficiently pressurized, it becomes “supercritical” and remains gaseous, while still exhibiting some of the properties of liquid CO2.
act as a solvent. Supercritical carbon dioxide acts as a solvent to extract essential oils without causing damage to plants.

CO2 Extraction vs. Steam Extraction

Some of the benefits associated with carbon dioxide that make it a better extraction option include:

a better result. Carbon dioxide extraction provides results that retain more plant-related odors and colors than extraction using steam-based methods.
No solvent. CO2 extraction reduces contamination by not using harmful solvents such as hexane, which are commonly used in extraction processes.
longer-lasting results. Essential oils extracted using this method retain their fragrance and have a longer shelf life.

Ethanol extraction vs co2 extraction

Which extraction method is better for consumers and producers? There is not an easy answer. In fact, there is no optimization method overall. Ultimately, it depends on what the producer needs to create. Here, we cover the most important factors to consider when making the choice between ethanol vs. CO2 extraction.


Out of all the methods available to producers, carbon dioxide is by far the most expensive method in terms of upfront costs. Processors must pay a steep price for a CO2 extraction system compared to lower-priced, entry-level ethanol and hydrocarbon units.

In terms of operating costs, there are a few variables to consider for each method. Ethanol extractions can include high variable costs and overhead due to the solvent price, ethanol losses, insurance premiums, hazardous waste disposal, and lower recovery. CO2 has low variable costs.

Food-grade ethanol is relatively safe and can reduce the likelihood of chemical contamination but it comes at a higher price. Denatured ethanol solvents are more affordable but include a wide range of non-food grade solvents. In comparison, CO2 has a low price per kilogram.

Ethanol as a solvent requires additional infrastructure investment due to the limits on ethanol storage, requirements for alarm lights, deflagration alarms, detectors, and a complete alarm system for gas detection. CO2 does not require any of these additional expenditures since there is no limit on the amount of CO2 that a facility can store on site.

Overall, CO2 extractions may cost more initially but can have lower operating costs that may pay for themselves in the long run. In the battle between ethanol extraction vs. CO2 extraction, it is hard to choose the optimization method in terms of cost.


For operators looking to make high-potency distillate, ethanol extraction is the way to go. Ethanol can extract a high amount of active compounds quickly to create a high-quality extract. For processors that want to create full-spectrum extracts featuring high concentrations of terpenes and cannabinoids as well as flavonoids and carotenoids, CO2 extraction may work for them. This method can help them produce a product that more closely resembles the plant material.

For many producers and consumers, CO2 extractions may reduce the risk of the carbon dioxide ending up in the final product compared to other methods that may leave behind residual solvents. When processors want to create pharmaceutical-grade products, CO2 may be a viable option.


Ethanol extraction is flammable, but not nearly as much as light hydrocarbons such as butane and propane.

However, for those that want peace of mind, CO2 can offer more safety than other extraction methods since carbon dioxide is not flammable and less toxic than ethanol. In addition, there is a lower risk of ending up with residual solvents in the end product.

Ethanol extraction can run the risk of leaving behind chemical contaminants that can increase the health risk for consumers (medical and recreational), especially when using denatured ethanol that includes non-food-grade chemicals.

While the process occurs at high pressure, peer-reviewed systems are designed to handle any risks associated with the high-pressure process.

However, CO2 is not entirely risk-free. If there is a leak in the room, it could replace the oxygen and suffocate operators. An adequate alarm system and sensors to detect leaks can offset these dangers.

In terms of solvent recovery, ethanol extraction requires more investments in the recovery process. Generally, CO2 extractions do not need to recover the solvent. However, they may want to recycle the carbon dioxide within a run or batch due to the affordability of CO2.

In terms of its effect on the environment, ethanol has a higher carbon footprint. The higher footprint comes from the production of the ethanol solvents, the high amount of energy needed to cool the system down to cool temperatures, and the environmental costs of disposing of the hazardous biomass waste.

CO2 extraction uses CO2, a byproduct of many industrial operations that is currently in the atmosphere. CO2 is non-toxic, renewable, and able to be recycled for use.

Efficiency and throughput

Ethanol extraction can process thousands of pounds of biomass per day with a single unit. Essentially, a processor’s efficiency and scale depend on the size of the unit.

Compared to ethanol, CO2 extraction is a lot slower. CO2 can perform considerably fewer runs per day compared to other extraction methods.

On the other hand, ethanol’s polarity as a polar solvent is also capable of dissolving water-soluble components in the material, which may require additional clarification steps to remove.

Biomass that has been processed by CO2 is cleaner and a good source of food-grade essential amino acids. Unlike ethanol, its transportation is not regulated.