Essential Methods of Edible Oil Extraction – Types, Pros, and Cons

11 Mar.,2024

 

Are you confused about the different methods of edible oil extraction, unsure which one to choose, or finding the best out of many? – If yes, then you have landed in the right place.


The market for edible oils is anticipated to increase rapidly, with a predicted value of USD 268.9 billion by 2027 (up from USD 212.6 billion in 2022), representing a CAGR of 4.8% from 2022 to 2027.

Among various oil seeds production, soybeans are among the leading types of oilseeds worldwide. The below mentioned graph will help you with more information about different oil seeds productions.

Moreover the global consumption of edible oil is also significantly increasing. The chart below can justify the global consumption of different oil year by year.


Hence, with the expansion of the edible oil market globally, finding the right method to extract oil or the right edible oil plant manufacturers is crucial for non-toxic, non-flammable, and environmentally friendly oil extraction.

Thus, in this blog, we will discuss different methods of edible oil extraction, their definitions, and their pros and cons. That will help organizations choose the most suitable method for oil extraction.

Moreover, this blog will go through unique reports that will help organizations understand the importance and benefits of different oil extractions easily.

Different extraction methods for edible oils

The process of extracting triglycerides from oilseeds can be done using a variety of methods, including chemical, biochemical, and mechanical techniques. These methods play a crucial role in determining the quality, flavor, and nutritional composition of the extracted oils.

From traditional techniques to modern advancements, each extraction method offers its own unique advantages and considerations. The goal is to maximize yields while minimizing changes to the quality of the product.

Mechanical extraction

Mechanical extraction is a method of oil extraction that uses pressure to force oil out of seeds. It is one of the oldest methods of oil extraction and is still commonly used in rural areas because it is relatively inexpensive and does not require highly trained personnel to operate the machines.

However, mechanical extraction usually results in a lower oil yield than other methods, such as solvent extraction. Hence, the oil yield from mechanical extraction can be improved by heating the seeds and using a screw press. The two most common types of mechanical presses are hydraulic presses and screw presses.

Hydraulic presses use a piston to apply pressure to the seeds, while screw presses use a rotating screw to force the oil out of the seeds. The detailed information about the most common types of mechanical presses—screw presses and hydraulic presses—is mentioned below

Screw press

A mechanical press called a screw press extracts oil from seeds by forcing the oil through a rotating screw. It is among the most widely used techniques for mechanical oil extraction.

A barrel with a helical screw inside makes up the screw press. As the seeds are fed into the barrel, the rotating screw extracts the oil from the seeds and forces it through a filter. The oil is then gathered and placed in a container.

Using a screw press over a hydraulic press has the advantage of better oil extraction and the ability to be adapted for continuous processing. A study found that the optimum oil yield for tobacco seeds is 73.38% when the seeds are heated to 70°C and the screw press is rotating at 32 rpm.

This means that the screw press will be able to extract the most oil from the tobacco seeds if these criteria are satisfied.

4 key features of screw press

Continuous process

The oil is continually extracted from the seeds as they are continuously fed into the barrel in screw presses.

High oil yield

Screw presses can extract a high percentage of oil from seeds, typically between 60% and 80%. This is higher than the oil yield from other methods of mechanical oil extraction, such as hydraulic presses.

Scalable

Screw presses are scalable, enabling them to handle higher production quantities. They are therefore a viable choice for both small- and large-scale oil extraction operations.

Durable

Screw presses are capable of withstanding the wear and tear that results from constant use. For companies who intend to use them for a long time, Screw presses make them a wise investment.

Hydraulic pressing

A hydraulic press applies force to the fruits or oilseeds in order to extract a high percentage of oil. The hydraulic press uses pressure to extract oil from seeds. The seeds are placed in a chamber, and a piston is forced down, applying pressure to the seeds. This pressure forces the oil out of the seeds through a filter and then gets collected in a container.

In comparison to other mechanical oil extraction techniques, hydraulic presses have a number of benefits. They are relatively inexpensive to operate, they do not require a lot of space, and they are also relatively easy to maintain.


4 features of Hydraulic pressing

Simple and economical

Hydraulic presses are relatively straightforward machines that don't need a lot of pricey machinery. They are a good choice for small-scale oil extraction operations because of this.

Effective

Oil extraction from seeds is a task best left to hydraulic presses. They can usually extract a large proportion of oil from the seeds, which helps reduce the cost of raw materials for enterprises.

Versatile

Oil may be extracted from a wide range of seeds using hydraulic presses. They are thus a fantastic choice for companies that want to create a wide range of oils.

Durable

Hydraulic presses are comparatively strong machinery that can endure the damage caused by prolonged use. They are therefore a wise investment for companies that anticipate utilizing them frequently.

Advantages and Disadvantages of Mechanical Extraction

Advantages DisadvantagesHigh efficiency and large-scale production capability. Can damage the plant material, which can reduce the quality of the essential oilCan be used for a wide range of plant materials. The lower yield of essential oil than other extraction methodsDoes not require the use of solvents Not suitable for all types of plant materialsSimple and cost-effective Heat and pressure during extraction can degrade or alter the quality of the extracted oil.

Chemical extraction

Chemical extraction is a method of extracting oil from oilseeds or fruits using chemical solvents. By utilizing specific solvents, this technique selectively separates desired components from the solid or liquid matrix in which they are naturally found.

Chemical oil extraction is widely employed in industries such as food and beverage, pharmaceuticals, cosmetics, and essential oil production. Its advantages include high selectivity, scalability, and the ability to process large quantities of raw materials, making it a preferred method for obtaining high-quality extracts.

There are several different types of chemical oil extraction, including solvent extraction, microwave-assisted extraction, supercritical fluid extraction, and enzymatic extraction.

The most common types of chemical oil extraction are solvent extraction and microwave-assisted extraction. The detailed information about both extractions is as follows

Conventional solvent extraction

A popular technique for effectively extracting oils and precious chemicals from numerous sources is conventional solvent extraction. This procedure makes use of solvents that can successfully extract oils from seeds or other raw materials by dissolving them. The solvents that can be used for CSE include hexane, acetone, ethanol, chloroform, and propane.

However, the most commonly used solvent for CSE is hexane, the colorless, flammable liquid is considered a good solvent for oil. A study reported that n-hexane can recover 37.03% of the oil from sesame seeds, while chloroform can only recover 6.73% and acetone can only recover 4.37%.

Moreover, the study also reports, solvent extraction is a superior oil extraction process than mechanical screw press method.

The solvent oil extraction process begins with cleaning and conditioning the seeds to remove dirt and debris and adjust the moisture content to the optimal level for extraction.

The seeds are then mixed with a solvent, such as hexane, in a closed vessel. The solvent dissolves the oil from the seeds, and the mixture is heated to increase the rate of extraction.

The solvent and oil mixture is then separated by distillation, and the solvent is evaporated, leaving behind the oil. The oil is then refined to remove impurities, such as free fatty acids, waxes, and color.

3 Features of conventional solvent extraction

High oil recovery rate

Up to 98% of the oil from seeds can be recovered using conventional solvent extraction. Compared to other oil extraction techniques, this one has a high oil recovery rate.

Cost-effective

The extraction of oil using conventional solvents is an economical process. The method is rather straightforward to carry out, and the solvents used are reasonably priced.

Simple to use

The extraction of oil using conventional solvents is a reasonably simple process. The technique is rather easy, and only a few pieces of equipment are needed.

Microwave-Assisted extraction

Microwave-Assisted Extraction is a relatively new method of oil extraction that uses microwaves to heat and denature the plant material, allowing for more efficient oil extraction. MAE has several advantages over traditional methods of oil extraction, including shorter extraction times, lower solvent requirements, and higher oil yields.

Studies have shown that MAE can produce high-quality oil with a lower unsaturated fatty acid content than other extraction methods. For example, a report found that MAE produced castor oil with a yield of 44.34%, while conventional solvent extraction only produced a yield of 35.2%.

Moreover,ther report found that MAE could be used to extract shea nut butter with a yield of 31.6% in 23 minutes at 75 °C. This is much faster and uses less solvent than conventional solvent extraction, which takes 10 hours at 65 °C with a solvent/solute ratio of 10:1.

3 Features of microwave-assisted extraction

Reduced environmental impact

By using less solvent and creating oil of higher quality that is less prone to go rancid, MAE can lessen the environmental impact of oil extraction.

Flexibility

A variety of oils can be extracted using MAE from various plant materials.

Easy to use

MAE is a pretty simple technique that doesn't need the usage of specialized tools.

Advantages and Disadvantages of Chemical Extraction

Advantages DisadvantagesCan extract a wider range of compounds, including those not easily obtained through other methods. Chemical extraction uses solvents, which can be harmful to the environment.Can achieve higher extraction yields compared to other methods. The solvent residues can remain in the essential oil, which can reduce the quality of the oil.Chemical extraction can produce reproducible results, which is important for quality control. Chemical extraction can damage the plant material, which can reduce the yield of essential oil.Chemical extraction is a fast and efficient process, which can be important for commercial applications. Requires the use of solvents, which may introduce impurities into the extracted oil.

CO2 oil extraction

CO2 oil extraction, also known as supercritical fluid extraction (SFE), is a method of extracting oil from various botanical materials using carbon dioxide (CO2) as the solvent. It is considered a more advanced and specialized extraction technique.

In this process, carbon dioxide is heated and pressured during supercritical fluid extraction until it reaches a state known as supercritical fluid. A supercritical fluid has the properties of both a gas and a liquid and is able to dissolve oil like a liquid, and also has the ability to flow like a gas.

The method of CO2 oil extraction is the oilseeds are placed in a chamber and the supercritical carbon dioxide is pumped in. The carbon dioxide dissolves the oil from the oilseeds, and the mixture is then heated.

The heated mixture is then pumped out of the chamber, and the carbon dioxide is evaporated, leaving behind the oil. Various types of CO2 oil extraction include

Subcritical CO2 extraction

Subcritical carbon dioxide extraction (SFE) is a method for obtaining oil from oilseeds by using carbon dioxide as a solvent. Heat and pressure applied to the carbon dioxide remain below the gas' critical points.

Subcritical CO2 can nevertheless extract some substances, notably those which are more polar or heat-sensitive while having a decreased solvating power.

This method is typically used for extracting delicate compounds such as volatile terpenes or temperature-sensitive components, while minimizing the extraction of chlorophyll and other unwanted compounds.

Batch SFE

In this kind of SFE, the supercritical carbon dioxide is poured into a chamber with the oilseeds. The carbon dioxide is evaporated while the oil is extracted. After that, the procedure is repeated until all of the oil has been taken out.


4 Features of CO2 extraction

  • Because the subcritical carbon dioxide does not harm the oil molecules, it results in a higher-quality oil.
  • Since carbon dioxide can be easily evaporated and recycled, the process is cleaner
  • Herbs, spices, flowers, and oilseeds are just a few of the botanical materials that can be extracted using CO2.
  • Because the carbon dioxide is food-grade and non-toxic, the method is safer.
Advantages and Disadvantages CO2 oil extraction

Advantages DisadvantagesCO2 is a non-toxic gas, so it is safe to use in food applications. The equipment required for CO2 oil extraction is expensive to purchase and maintain.CO2 is a solvent, but it is not a chemical solvent. This means that the oil extracted using CO2 is free of any solvents, which can be a selling point for consumers who are looking for a healthier option. CO2 oil extraction can have a lower extraction yield than other methods, such as solvent extraction. This means that less oil is extracted from the plant material.CO2 is a naturally occurring gas, so it is not harmful to the environment. In fact, CO2 can be recycled and reused, which makes CO2 oil extraction a sustainable process. CO2 oil extraction requires high pressure and temperature, which can be a safety hazard. This is because the high pressure and temperature can create a risk of explosion or fire.

Enfleurage oil extraction

Traditional techniques like enfleurage are used to draw essential oils from delicate flowers, especially those that are too delicate to tolerate steam distillation's high temperatures. Since more effective extraction techniques are now available, this labor-intensive approach, which has been around for centuries, is becoming less popular.

Enfleurage is derived from the French verb enfleurer, which means "to fatten." The essential oils obtained by enfleurage are extremely delicate and have a strong aroma. They are frequently found in expensive perfumes.

Types of Enfleurage oil extraction

Cold Enfleurage

To make essential oils from flowers, you need a frame with a glass bottom, a fat, fresh flowers, and a clean, dry place to work. First, spread a layer of fat on the bottom of the frame. Then, place the flowers evenly on the fat, making sure they don't overlap. Cover the frame with a piece of glass or plastic wrap and let it sit for 24-48 hours.

During this time, the flowers will release their essential oils into the fat. After 24-48 hours, remove the flowers and replace them with fresh ones. Repeat steps 3-5 until the fat is saturated with the essential oils from the flowers.

Once the fat is saturated, you can extract the essential oils by dissolving the fat in alcohol. The alcohol will dissolve the essential oils, leaving behind a clear liquid. The essential oils can then be diluted with a carrier oil to make them more suitable for use.


Hot Enfleurage

This technique involves gently heating the greased plates covered with flowers to hasten the release of the flower's fragrant chemicals into the fat or oil. Fresh flowers can be used throughout this procedure until the fat or oil reaches its saturation point.


3 Features of Enfleurage oil extraction

  • It is a very gentle process that does not damage the flowers. The flowers are only laid on top of a layer of pure fat, and as time passes, the essential oils gradually permeate the fat.
  • It generates extremely pure and potent essential oils. Because they are not diluted with any other solvents, the essential oils extracted by enfleurage are extremely pure.
  • The aroma of the essential oils lingers for a while. Because they are not volatile, the essential oils obtained by enfleurage have a persistent smell. This means that they won't quickly vanish but will last.
Advantages and Disadvantages Enfleurage oil extraction

Advantages DisadvantagesEnfleurage can produce highly fragrant and true-to-nature aromatic compounds. Enfleurage is a time-consuming and labor-intensive process, making it less practical for large-scale production.It is particularly suitable for extracting fragrances from delicate flowers that cannot withstand high temperatures. The use of animal fat in traditional enfleurage raises ethical concerns, and alternatives like vegetable oils may not capture the exact aroma as effectively.Enfleurage does not use any solvents, which makes it a very environmentally friendly process. Enfleurage has a low yield of essential oils. This means that a lot of flowers need to be used to produce a small amount of essential oil.

Conclusion

The methods of edible oil extraction offer various advantages and disadvantages, depending on the desired outcome and specific considerations. Choosing one of the best methods of edible oil extraction might be challenging for you.

However, before choosing the best method, you should consider a few factors that include quality, safety, yield, cost, sustainability, flavor, and aroma. In addition, it is crucial to choose the right edible oil plant manufacturer, as they play a vital role in ensuring the efficiency and reliability of the extraction process.

A reputable manufacturer will provide high-quality equipment and technology, offer comprehensive support and service, and adhere to industry standards and regulations.

By carefully evaluating these factors, one can make an informed decision to ensure the extraction process aligns with their specific needs and priorities for obtaining high-quality edible oils that are safer and healthier for humans to consume.

Moreover, by getting in touch with the right oil refinery plant manufacturers is advisable for high-quality, non-toxic, and environmentally friendly oil extractions.

With high quality products and considerate service, we will work together with you to enhance your business and improve the efficiency. Please don't hesitate to contact us to get more details of best oil press machine.