What Are Herbal Extracts? [9 Methods and Uses]
As a gardener, I love drying herbs and using them as my daily routine. They give nutrients; however, I found out that there are better ways of extracting nutrients from herbs apart from drying.
Herbal extracts are liquid substances made by extracting parts of herbal raw materials with an aid of solvents. It is widely used in the cosmetics, food, and medicinal industries. Several extracting methods can be done to achieve a good quality of herbal extracts.
Let us dig further into the information below to know which extraction method suits your needs.
Steps in Herbal Processing
The practice of processing natural products is very important. Planting and harvesting stages must be considered in the entire process to acquire the desired quality of extracts.
Every plant matures in different cycles. This suggests that when you want to extract the botanical essentials of your plants, the harvesting stage must be optimized. The leaves, stems, and roots are primary parts of the herbal plants that provide optimal results when doing the extraction process. The guidelines below will help you in the harvesting stage.
|Parts of the Plants||Harvesting Stage|
|Whole plant or aerial||Initial ﬂowering|
|Roots or rhizomes||Full maturity. The maturity stage of the species must be ﬁrst determined.|
|Leaves||Fully developed leaves|
|Stems or bark||At the beginning of the rainy season. The maturity stage of the species must ﬁrst be determined.|
|Wood||Toward the end of the rainy season.|
|Flowers||At the beginning of the blooming period.|
|Seeds||Fully matured fruit.|
Before processing the harvested herbal plants, they must be protected from rain, direct sunlight, moisture, and other factors that might cause mold growth, aflatoxin formation, fermentation, and thermal degradation. They must be stored in containers that are well ventilated and be protected from insects, livestock, domestic animals, and pests.
5 Primary Steps in Herbal Processing
The primary steps in herbal processing are 1) sorting 2) washing 3) parboiling (blanching) 4) leaching and 5) drying
Like any food, especially raw products, we always do the necessary preparations from cleaning until it will be served on the table. The same thing will happen if we extract botanical essentials from our herbal plants. Below are the primary steps that we should follow:
- Parboiling (Blanching)
Sorting is the first step to ensure the cleanliness of the herbal plant materials by removing the unwanted parts that are not useful in the extraction process.
After gathering the raw plant materials, you should remove unwanted dirt like soil, dust, mud, and stones. Remove the insects, rotten parts, and residuals of non-useful parts from the herbal plant. Separating the medicinal parts of the herbs from the non-medicinal part is highly important to achieve high-quality results. This will also give you the assurance that the herbs you are using are free from harmful micro-bacterial organisms.
This process involves hand operation processes such as peeling, sieving, trimming, and singeing. There are possible accidents that might happen in this process, such as cuts, insect bites or stings, and allergic reactions. So, I would recommend protecting yourself with some basic tools such as gloves, dust masks, and other gardening tools which you can buy on Amazon.
The raw plant materials, especially the roots, rhizomes, and tubers, must be washed with clean water and dried right after the harvest.
You might need to scrape or brush some parts in this process, especially the roots. Change the water frequently and be mindful that it is highly not recommended to soak the plant in the water.
3. Parboiling (Blanching)
Parboiling or blanching is the process in which some raw plant materials are put into boiling water for less than a minute or more, depending on the material without being fully cooked.
This heating procedure improves the storage life of your processed herbal materials by gelatinizing, and it prevents the contamination of molds and insects. However, you must be extra cautious of not over boiling the raw materials because it will damage tissue cells and there will be nutrient denaturation due to the heat treatment. Therefore, you have to blanch them between 55℃-75℃ to tone down quality problems.
This is the process of removing some impurities from the raw plant materials over running water.
After blanching your plant raw materials, you may see some particles that float in hot water. Some impurities have been removed, but some are with your herbal materials. To remove the remaining impurities, you have to wash the plant materials over running water for 10 to 20 seconds. Supposing that you will not control the length of leaching, there will be an excessive loss of other nutrients from the plants, which you need to avoid.
Drying is the final stage in the primary steps of herbal processing. All plant materials must be dried after sorting, washing, blanching, and leaching.
If you do not dry your plant materials after going through several steps of cleaning them, they will be damaged by mold growth and other microbial infestations. Drying will avoid the plant’s deterioration of tissue and phytochemical alteration caused by the actions of harmful organisms. Drying will also help grinding and milling, which converts the herbal materials into a more convenient form for the next processing series.
Proper drying of raw plant materials involves three key aspects: temperature, humidity, and airflow. This will affect the quality of the desired herbal materials.
You have to choose the appropriate drying condition for the type of plant material that will undergo the extraction process. If they are dried in the wrong method, their valuable botanical essentials will be wasted, and so with your effort. Let us check which three drying processes are suitable for your herbal materials.
- Drying by Artificial Heat
Sun-drying is the process of exposing plant materials in the open air and under direct sunlight.
If you dry your herbal plant materials, they should be evenly spread out in thin layers on the drying frame and must be kept away from contaminants such as smoke coming from vehicles, heavy dust, rain, and insects. The drying frames must be at least 15cm above the ground.
You have to exert effort to turn the herbal materials every hour to avoid mold growth and achieve uniform drying. Once the plant materials are dry, transfer them in a container or indoor to avoid loss of botanical essential components due to evaporation. You can use this herb drying rack on Amazon.
Shade-drying is the process of drying herbs indoors or in the shade to avoid direct sunlight exposure.
I use this drying method in my moringa and oregano at home. This process is slow, but I prefer this drying to maintain the color of the leaves and the essential nutrients for my tea. I also make sure that I place the drying frames in a room with a temperature between 20℃ and 22℃ with the aid of an electric fan for airflow circulation.
Drying by Artificial Heat
Drying by artificial heat is a drying process that is faster than open-air drying. It is highly recommended during rainy seasons and in places where humidity is high.
If you prefer this method, you may use an oven, stove, and other heating devices or open fires. When using open fires, the area must have good ventilation. However, if you can avoid using open fire, you have to do so because combustion residues might contaminate the herbal materials.
The recommended temperature for artificial-heat drying is below 65°C for barks and roots while below 40°C for leaves, herbs, and flowers.
3 Secondary Steps in Herbal Processing
Secondary steps in herbal processing are used to process some herbal materials that require specific processing to improve the purity and quality of the final product.
When herbal plant materials undergo organic processing, we always believe them to be healthier compared to those chemically processed plant materials. However, not all herbal extracts can be achieved using the primary steps. Let us find out below the other steps in processing your herbs at home.
- Cutting, Sectioning, and Comminution
Cutting, Sectioning, and Comminution
When the herbal materials are thoroughly dried, they are processed by cutting and sectioning into specific shapes and sizes or decoction slices for further processing until the desired product is achieved.
Do you take herbal food supplements in a capsule? Are you not wondering how they are made? Finally, I discovered that this method answers this question. The cut herbal pieces are comminuted or pulverized, placed inside a capsule and there we have the finished herbal products.
The best examples are the white or red ginseng products that we see in the market presented as roots pieces, slices, and powder. They are the finished products derived from this process.
Aging and Sweating
Aging and sweating are processes of drying for a longer period to prepare the herbs for further processing.
Let us continue reading to know their differences.
Aging (wilting) is the process that stores herbal materials under the sun or in the shade for up to 1 year after harvest. The excessive water content of the herb is evaporated and enzymatic reactions may occur to change the chemical composition of the herb.
For example, cascara (frangula purshiana) bark must be aged for a year before using it in any medicinal preparations. If this process is not properly done, the person may experience vomiting and stomach ache.
Sweating is the process of keeping the herbal materials at 45-65°C temperature for a week up to a couple of months to oxidize or hydrolyze some chemical composition of the herb.
For example, vanilla beans are known to undergo repeated sweating between woolen blankets under the sun during the day and packed in wool-covered boxes at night for two months. According to WHO the vanilla pods will lose 80% of their weight and take the color and odor of the commercial drug.
Stir-frying is the process of putting and stirring or tossing herbal materials in a pot or frying pan under low heat until the material is carbonized or its color changes or charred.
Depending on the kind of herbal plant materials, adjuvants (solvents) such as wine, vinegar, honey, saline, and ginger juice may be added in this process. For example, the roots of licorice (glycyrrhiza glabra), rhizome, and Astragakus mongolicus are mostly stir-fried with honey. Salvia miltiorrhiza roots are stir-fried wine while ginger and fresh ginger are stir-fried with sand until the color turns brown. In some instances, ginger can be stir-fried over an intense fire until carbonized for decoction.
4 Major Herbal Extraction Procedures
Comminution is the process of drying the herbal plant materials and reducing them to small pieces.
If you are using fresh materials, it is essential to do the extraction immediately to prevent deterioration and microbial infestation. Powdering or pulverizing your herbal plant materials ruptures their cell tissues and structures, exposing and preparing their chemical composition to the extraction solvent.
What happens when your communition is overdone?
Excessive grinding will lessen the botanical essentials of your herbal materials because of the mechanical heating from the equipment. Moreover, extremely fine powder will block the extraction filter, preventing or slowing down the filtration process.
Extraction is carrying out the botanical essentials with the aid of selected solvent at a specific temperature depending on the herbal plant materials.
The common solvents that you can use in the extraction process are hexane, dichloromethane, ethyl acetate, methanol (or ethanol), vinegar, glycerine, carbon dioxide, and water. However, it would help if you were extra careful in choosing which solvents to prevent serious health injuries.
Filtration is obtaining the extracted liquid and separating it from the marc through a filter cloth or paper to remove the insoluble residues.
In this process, you may use decantation, centrifugation, or straining depending on the matrix and extraction method you want to use.
Concentration is removing excess solvent produced after the filtration process is done. This involves evaporation under reduced pressure, freeze-drying, or spray-dying.
The extracts in a liquid form will flow through a pipeline directly into a concentration system. The liquid slowly condenses at low-temperature evaporation, which preserves the potency of the herbal extract. Too much exposure of extracts at high temperatures will damage their quality.
9 Herbal Extraction Methods
The type of extraction process can greatly affect the nutrients of the final product.
There are different processing and methods in herbal extraction.
- Supercritical Fluid Extraction (SFE)
- Microwave-Assisted Extraction (MAE)
- Sonication Extraction
- Soxhlet Extraction
- Hydro-distillation Extraction
- Steam-distillation Extraction
- Ultra-high Pressure Extraction
- Accelerated Solvent Extraction (ASE)
- Hot Water Extraction
1. Supercritical Fluid Extraction (SFE)
Supercritical fluid extraction It is the process of separating a plant component from another using carbon dioxide CO₂ at an elevated temperature of 31℃ and critical pressure of 74 bar to extract soluble compounds from raw materials.
Using the SFE method on herbs gives us the highest quality of extracts with a high concentration free from residual solvents. We are guaranteed fresh flavor, active pharmaceutical ingredients (API), and the purest fragrance for everything in the food, beverage, pharmaceutical, and cosmetics industries. It also increases the shelf life of the extracts and oils.
Below are the procedures of how SFE works.
- Place the raw plant material into the extractor.
- Inject the Carbon Dioxide CO₂ through the pipe by pressuring it. The CO₂ is superheated before it is pushed through the extraction bin.
- CO₂ liquid is forced into the plant material diluting the plant’s flavor, aroma, color, and active pharmaceutical ingredient (API).
- The extracts are directed through a separator and the CO₂ is recycled into the buffer tank to await the next cycle of extraction.
Advantages of Supercritical Fluid Extraction (SFE)
- CO₂ is non-toxic, non-flammable, odorless, tasteless, inert, and inexpensive.
- CO₂ is known to be perfectly adapted in food, aromas, essential oils, and nutraceutical industries.
- Recycling CO₂ can be achieved for all methods.
- Pure extraction yield can be attained.
Disadvantages of Supercritical Fluid Extraction (SFE)
- Loss of desired compounds with improper solvent selection.
- Specialized equipment is required.
2. Microwave-Assisted Extraction (MAE)
Microwave-assisted extraction (MAE) is a process of extracting active ingredients from herbs by using a liquid (solvent) such as alcohol and water.
This method is innovative, economical, and environmentally friendly because there are no harmful by-products added to the raw material. Moreover, we can save time in this method since we can extract the essential botanicals in minutes instead of hours.
The process of (MAE) is as follows.
- Heat the raw material in the microwave.
- The microwave energy will heat the herbal particle which is inside the cell of the raw material.
- The cell will explode and will produce all the bioactive compounds of the raw material which will be extracted.
Advantages of Microwave-Assisted Extraction (MAE)
- Applicable for both industrial and laboratory scales.
- Less time-consuming than conventional methods.
- Can provide high returns on capital investment.
Disadvantages of Microwave-Assisted Extraction (MAE)
- Efﬁciency of microwaves is very poor for nonpolar target compounds or solvents or for extremely viscous solvents.
- Not appropriate for heat-sensitive compounds.
- Expensive equipment and difﬁcult to operate.
3. Sonication Extraction
Sonication extraction is the process of using ultrasonic equipment to facilitate the extraction of herbal plant material.
The time and conditions in this process are similar to MAE. Sonication Extraction uses ultrasonic equipment while MAE uses a microwave. The solvent extraction of herbal plant materials in sonication is optimized through the ultrasound process’s mechanical effects. This results in improved solvent penetration into the cellular materials within the herbal cess, leading to the release of herbal oils.
Advantages of Sonication Extraction
- Efﬁcient tool for large-scale commercial applications.
- Reduced working time and easy to handle.
- Increased yield, reduced solvent consumption, and high extract quality.
Advantages of Sonication Extraction
- The active part of ultrasound is only the vicinity of the ultrasonic emitter.
- The presence of a dispersed phase contributes to the ultrasound wave attenuation.
- Weak effect on the extraction of oil.
4. Soxhlet Extraction
Soxhlet extraction is an inexpensive technique for extracting herbal phytochemicals using a soxhlet apparatus. This is also used to compare the newer extraction techniques done in the plant materials.
- Place the sample in a thimble holder and gradually fill it with fresh solvent using a distillation flask.
- When the liquid reaches the overflow level, a siphon aspirates the solute from the thimble holder, moving the aliquot back into the distillation flask carrying the extracted analytes into the bulk liquid.
- This process continues until the extraction process is completed.
Advantages of Soxhlet Extraction
- It is a very simple and inexpensive method.
- The temperature in the extraction system can be maintained.
Disadvantages of Soxhlet Extraction
- It requires excessive extraction times.
- It uses large amounts of extractants (solvent).
- No agitation can accelerate the process.
- There is thermal decomposition of heat-sensitive compounds.
5. Hydro-distillation Extraction
Hydro-distillation is the process of boiling the mixture of solvent and plant raw materials to get the extract.
- Place the sample and solvent in the retort.
- Apply heat to vaporize the mixture.
- The steam transports the extracted oil in the vapor phase into the condenser, where the condensate liquid mixture forms.
- The liquid mixture then ﬂows into a separator where water and the essential oil are separated by density difference.
- The water-rich phase, which contains some plant essence, is called “hydrosol.”
Advantage of Hydro-distillation Extraction
- Inexpensive method because no organic solvent is required.
Disadvantages of Hydro-distillation Extraction
- A prolonged time period is necessary to separate water from the product.
- No agitation to accelerate the process.
- Risk of thermal degradationEnergy consuming.
6. Steam-distillation Extraction
Steam-distillation is the process of supplying steam to the mixture of solvent and plant raw materials using a steam generation apparatus.
- Fill the bottom flask with distilled water.
- Above the bottom flask is an alembic chamber, where you place the plant material called biomass which contains essential oil.
- When the water boils, the steam passes up into the chamber and the plant material. The steam temperature causes the tiny sacs to burst and releases essential oil.
- The essential oil rises up with the steam back into the liquid which drops out of the tube.
- The liquid is collected in a new reservoir where the water and oil are separated naturally.
- The water called hydrosol is left at the bottom while the oil rises to the top.
- Collect the oil and place it in a clean container.
Essential oils and hydrosols are good products used for skincare regimens, health supplements, and even home cleaning. To see the entire process and experience the entire benefits of these extracts, you must buy this Home Distilling Kit on Amazon.
Advantage of Steam-distillation Extraction
- Can extract water-insoluble compounds.
Disadvantage of Steam-distillation Extraction
- No agitation is needed to accelerate the process.
7. Ultra-high Pressure Extraction
High pressure in this type of extraction method refers to cold, isostatic ultra-high hydraulic pressure.
- Mix raw herbs and solvent together in a polyethylene bag and seal after removing the bubbles.
- Place the bag in a pressure vessel equipped with a temperature controller and pressure valve to release excess pressure.
- Fluid was used to apply pressure to the vessel using an ultra-high pressure booster pump.
- Extraction was carried out at high pressure (100 MPa to 1,000 MPa) and at room temperature for a speciﬁed duration (5 to 15 minutes).
- After the extraction process, the mixture undergoes filtration and concentration stage using a rotary evaporator.
Advantage Ultra-high Pressure Extraction
- Short extraction time
Disadvantage Ultra-high Pressure Extraction
- Compound impurity issue
8. Accelerated Solvent Extraction
Accelerated Solvent Extraction is a process that is performed at temperatures (50 to 200℃) and at pressures between 10 and 15 MPa maintaining the solvent in liquid form. This process enhances the solvent diffusivity and accelerates the extraction process.
- The sample, together with the solvent is placed in the closed container inside the pressure vessel.
- The container is connected to a thermocouple to detect temperature change in the sample container.
- If temperature change occurs, the heating and cooling jacket (surrounding the sample container) will operate in order to keep constant the temperature inside the sample container. The pressure, on the other hand, is controlled by the pressure relief valve.
- When the pressure increases, the pressure relief valve will be opened to prevent pressure from building up.
- When the pressure decreases, the pressurization system will apply pressure to the vessel. Note that, pressure is only created when the pressure inside the vessel drops below the set pressure, thereby saving the pressurization energy during the extraction process.
Advantages of Accelerated Solvent Extraction
- A potential alternative technique to SFE for the extraction of polar compounds.
- Reduce solvent consumption and extraction time.
Disadvantages of Accelerated Solvent Extraction
- Only suitable for the extraction of a high-temperature stable compound
9. Hot Water Extraction (HWE)
Hot water extraction (HWE) belongs to the same category as the ASE process. The HWE however uses hot water for extraction instead of an organic solvent.
Advantages of Hot Water Extraction
- Inexpensive method because no organic solvent is required.
- Extract essential oil with high oxygenated components.
- Substantial saving of both energy and investment costs.
Advantages of Hot Water Extraction
- Not suitable for heat-sensitive compounds.
How to Produce Herbal Extract at Home
Producing herbal extract with the aid of a machine requires a lot of resources and can be dangerous to someone who is not an expert.
You don’t need to buy expensive extracting machines to achieve the desired quality of your herbal extract. It would be very impractical if you are not going to maximize the use of the equipment after trying. If that is the case, you would probably ask how to produce herbal extract at home. By following the procedure below, you will enjoy your herbal extract.
- Measuring Container
- Glass Jar with Cap
- Dried Herbal Plant Material
- 600 grams vegetable glycerin
- 200 grams potable water
- Prepare all the materials needed.
- Mix the 600 grams glycerin and 200 grams of water in a container until the color of the mixture is clear.
- Pour the dried herbal plant material inside the glass jar until ⅔ of the container is filled.
- Pour the glycerin and water mixture into the glass jar until full.
- Cover the container and label the herbal plant material and the date.
- Store it for six weeks, but you have to mix it by shaking the container thrice a day.
- After six weeks, you can enjoy your herbal extracts.
You may use fresh herbal plant material but dry them for about 20 minutes to lessen the water content of the plant. When there are lots of water in the mixture, fungi and other bacteria will grow. You have to note that the life shelf of an extract is 1 to 2 years.
Many people are now using organic products for several reasons. Continue reading to know the benefits of using herbal extracts.
Benefits of Herbal Extract Use
Herbal extracts are widely used as 1) organic health supplements and immunity booster 2) spice and herbs in cooking 3) organic treatment in maintaining and enhancing body appearance.
In general, people use herbal extracts because of the following.
- Herbal extracts have concentrated medicinal properties that provide nutrients to our bodies and boost our immune system. The presence of active components is easily absorbed by our body which leads to a quicker desired result rather than consuming the whole herbs.
- Herbal extracts are frequently used as food additives because it contains bioactive compounds such as polyphenols and carotenoids that help in antimicrobial and antioxidant activity. Apart from enhancing the food’s flavor and aroma, they also increase the shelf life of the food and improve its color. Their organic compounds of herbal extracts are the best alternative for ingredients rich in synthetic compounds that have harmful toxins and carcinogens.
- Herbal extracts are commonly used in beauty regimens. Many herbs are rich in antioxidants that help in repairing damaged skin and hair cells, reduce early aging, and make your skin glow. They also whiten the teeth and fight tooth decay.
Now that we learn a lot about herbal extracts from processing to their uses, let us find out the difference between herbal extracts from other forms of preparation for extractions.
Herbal Extract vs Tincture?
All tinctures are extracts, but not all extracts are tinctures. The tincture is the ethanol extract of plant material while the herbal extract is the phytochemical composition of a plant material
Both herbal extracts and tinctures may come from the same plants, but they only differ in the level of concentration.
Herbal extracts have a 1:1 ratio of herbal material to the solvent resulting in a highly concentrated finish product. It undergoes a complicated extraction process which loses some essential oils due to long storage periods. It is easy to store and has a longer shelf life than tinctures.
Tinctures have a 1:6 or 1:8 ratio of the raw material to the solvent resulting in a less concentrated finish product. They undergo easy extraction procedures in which the starting point of the process begins from the point of harvest. Tinctures can be used or mixed in foods and drinks such as smoothies, soups, and salad dressings. They are mostly preferred by people because they only contain 7 calories per milliliter compared to other baked pastries that contain 100-200 calories.
Herbal Extract vs Essential Oil?
The herbal extract is the phytochemical composition of the herbal plant while the essential oil is the oil (hydrophobic liquid) of the plant which contains the aroma and essential characteristics of the plant.
Essential oils are taken from aromatic parts of the plants such as roots, flowers, and leaves through distillation. They are commonly used for massage and other aromatherapy sessions which give you a relaxing experience. Moreover, essential oils are effective in beauty for your daily beauty routines. They are rich in antioxidants which help in repairing damaged hair and skin cells, and reduce or slow down aging. This will help you look younger and healthier.
Herbal extracts as described above are phytochemical components of an herb in the form of a liquid. They are best for cooking as they contain organic compounds that will boost our immune system protect our body from the usual eating of foods rich in synthetic compounds
In general, whole herbs, tinctures, and essential oils are all good as they are organic in nature. Choosing the best among the three depends on the condition and your preference. If you want a faster effect, use herbal extracts as they are well concentrated. If the extraction process is the problem, you can opt for tinctures as they can be easily processed without the aid of costly machines. If you want to use it for beauty enhancement, use essential oils as they are good for external use. Your skin pores and hair follicles can easily absorb the nutrients they need.
Summary of What are Herbal Extracts
- Herbal extracts are liquid substances made from the extraction process with the aid of solvents.
- There are different extraction methods that you can choose from depending on the condition of the herbal plant material and your desired finished products.
- Herbal extracts can be used in aromatherapy sessions, treat different diseases, and health supplements.
- Herbal extracts are more concentrated, effective, and potent than tinctures and whole herbs.
“Herbal Processing and Extraction Technologies” by S.N. Azmin et al. in Separation & Puriﬁcation Reviews
“Herbal Extracts and Phytochemicals: Plant Secondary Metabolites and the Enhancement of Human Brain Function” by D.O. Kennedy et al. in Oxford Academic
“WHO Guidelines on Good Herbal Processing Practices (GHPP) for Herbal Medicines” in World Health Organization
“A Guide to Common Medicinal Herbs” in Health Encyclopedia
“Supercritical Fluid Extraction” by G.N. Sapkale et al. in Sadguru Publications
“The Benefits of Plant Extracts for Human Health” by Charalampos Proestos in NCBI
“Microwave-Assisted Extraction” by Thomas Michael in Natural Product Extraction
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