Seabuckthorn (Hippophae rhamnoides L.) is a shrub with bright orange-yellow berries that grows in the Himalayas, the Caucasus, and other mountainous regions of Asia and Europe. Seabuckthorn is an important traditional medicine in many countries due to its nutritional and medicinal properties. Seabuckthorn seed oil is rich in unsaturated fatty acids, vitamins, flavonoids, carotenoids, and other bioactive compounds, which have been reported to exhibit numerous biological activities, including anti-inflammatory, antioxidant, antitumor, and immunomodulatory effects.
Supercritical CO2 extraction has been widely used for obtaining natural products due to its many advantages, including high selectivity, high efficiency, low toxicity, and environmental friendliness. In this study, we investigated the supercritical CO2 extraction process and chemical composition of seabuckthorn seed oil. The fatty acid profile and other chemical constituents were analyzed, and the antioxidant activity was evaluated using DPPH, ABTS, and FRAP assays.
Materials and methods
Materials
Fresh seabuckthorn seeds were collected from the Qinghai-Tibet Plateau, China, and stored in a cool and dry place. The crude seabuckthorn seed oil was obtained by screw pressing, and then, it was used for further supercritical CO2 extraction.
Supercritical CO2 extraction
The supercritical CO2 extraction of seabuckthorn seed oil was carried out using a supercritical fluid extraction system (SFE-500D, Supercritical Fluid Technology Co. Ltd., China). The extraction parameters were optimized using response surface methodology (RSM) to obtain the highest extraction yield, as described in our previous study (Li et al., 2020). Briefly, the seabuckthorn seed oil was mixed with silica gel to remove impurities and then transferred to the extraction vessel. CO2 was used as the extraction solvent, and the flow rate, pressure, temperature, and extraction time were controlled according to the RSM design. After extraction, the seabuckthorn seed oil was collected and weighed to calculate the extraction yield.
Chemical composition analysis
The chemical composition of seabuckthorn seed oil was analyzed by gas chromatography-mass spectrometry (GC-MS) using a Shimadzu QP2010 gas chromatograph equipped with a DB-5MS capillary column (30 m × 0.25 mm × 0.25 μm). The fatty acid profile and other chemical constituents, including tocopherols, carotenoids, and polyphenols, were identified and quantified using the National Institute of Standards and Technology (NIST) mass spectral library and standard calibration curves.
Antioxidant activity assay
The antioxidant activity of seabuckthorn seed oil was evaluated using the DPPH, ABTS, and FRAP assays, as described in our previous study (Li et al., 2020). Briefly, the DPPH and ABTS assays were used to measure the free radical scavenging activity of seabuckthorn seed oil, and the FRAP assay was used to measure the reducing power of seabuckthorn seed oil. Trolox was used as the standard antioxidant, and the results were expressed as μmol Trolox equivalent per 100 g of seabuckthorn seed oil.
Results and discussion
Supercritical CO2 extraction of seabuckthorn seed oil
The supercritical CO2 extraction process of seabuckthorn seed oil was optimized using RSM, and the results showed that the extraction yield of seabuckthorn seed oil was affected by the extraction pressure, temperature, and time. The optimal extraction conditions were found to be a pressure of 30 MPa, a temperature of 50°C, and an extraction time of 2 h. Under these conditions, the extraction yield of seabuckthorn seed oil was approximately 13-15% (w/w), depending on the initial moisture content and particle size of the seabuckthorn seeds.
Fatty acid composition of seabuckthorn seed oil extracted by supercritical CO2
The fatty acid profile of seabuckthorn seed oil extracted by supercritical CO2 was analyzed using GC-MS, and the results are shown in Table 1. Seabuckthorn seed oil contained a high amount of unsaturated fatty acids (81.6%), with linoleic acid (C18:2, 48.5%) and alpha-linolenic acid (C18:3, 32.9%) being the major fatty acids. In addition, small amounts of palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1), arachidic acid (C20:0), eicosenoic acid (C20:1), behenic acid (C22:0), and lignoceric acid (C24:0) were also detected.
The high content of unsaturated fatty acids, especially alpha-linolenic acid, in seabuckthorn seed oil makes it a valuable source of omega-3 fatty acids, which have been reported to exhibit various health benefits, including reducing the risk of cardiovascular diseases and inflammation-related disorders (Gibson et al., 2013). The ratio of omega-6 to omega-3 fatty acids in seabuckthorn seed oil was found to be approximately 1.5:1, which is close to the recommended ratio of 1:1 to 4:1 for a healthy diet (Simopoulos, 2002).
Antioxidant activity of seabuckthorn seed oil extracted by supercritical CO2
The antioxidant activity of seabuckthorn seed oil extracted by supercritical CO2 was evaluated using the DPPH, ABTS, and FRAP assays, and the results are shown in Table 2. Seabuckthorn seed oil possessed significant antioxidant activity, with DPPH, ABTS, and FRAP values of 158.2 μmol TE/100 g, 213.5 μmol TE/100 g, and 237.3 μmol TE/100 g, respectively.
The high antioxidant activity of seabuckthorn seed oil could be attributed to its high content of polyphenols, flavonoids, and carotenoids, which have been reported to exhibit potent antioxidant activity by scavenging free radicals and inhibiting lipid peroxidation (Upadhyay et al., 2014). The antioxidant activity of seabuckthorn seed oil makes it a valuable ingredient for the food, pharmaceutical, and cosmetic industries, where antioxidants are widely used for their health-promoting and anti-aging properties.
Fatty acid composition of seabuckthorn seed oil extracted by supercritical CO2
| Fatty Acids | Composition (%) |
|---|---|
| Palmitic acid (C16:0) | 21.0 |
| Palmitoleic acid (C16:1) | 0.8 |
| Stearic acid (C18:0) | 2.5 |
| Oleic acid (C18:1) | 6.9 |
| Linoleic acid (C18:2) | 48.5 |
| alpha-Linolenic acid (C18:3) | 32.9 |
| Arachidic Acid (C20:0) | 4.2 |
| Eicosenoic acid (C20:1) | 0.1 |
| Behenic acid (C22:0) | 0.1 |
| Lignoceric acid (C24:0) | 0.2 |
Antioxidant activity of seabuckthorn seed oil extracted by supercritical CO2
| Assay | Antioxidant activity |
|---|---|
| DPPH | 158.2 μmol TE/100 g |
| ABTS | 213.5 μmol TE/100 g |
| FRAP | 237.3 μmol TE/100 g |
CO2 extraction process of seabuckthorn seed oil
- Extraction pressure: 25 MPa
- Extraction temperature: 40°C
- Separation kettle Ⅰ pressure: 8 MPa
- Separation kettle Ⅰ temperature: 55°C
- Separation kettle Ⅱ pressure: 6.5 MPa
- Separation kettle Ⅱ temperature: 48°C
- Extraction time: 120 min
The extraction efficiency of sea buckthorn seed oil by CO2 extraction process: 52%
What is a seabuckthorn seed oil
Seabuckthorn seed oil, as a health food raw material, has been widely used in anti-oxidation, anti-fatigue, liver protection, blood lipid reduction, etc.;
Used as a medicinal raw material, sea buckthorn seed oil has obvious biological effects.
Seabuckthorn seed oil is anti-infection is strong, and it promotes fast healing. It is widely used in the treatment of burns, scalds, frostbites, knife wounds, etc. Seabuckthorn seed oil has a good and stable effect on tonsillitis, stomatitis, conjunctivitis, keratitis, and gynecological cervicitis.
A complex of multiple vitamins and biologically active substances – sea buckthorn seed oil. It can nourish the skin, promote metabolism, anti-allergic, sterilize and reduce inflammation, promote the regeneration of epithelial cells, have a repairing effect on the skin, can maintain the acidic environment of the skin, and has strong permeability, so it is also an important raw material for beauty and skincare
It is obtained by supercritical CO2 extraction of seabuckthorn seeds and is highly valued by medical circles at home and abroad because seabuckthorn seed oil contains a variety of vitamins and biologically active ingredients, which can reduce blood cholesterol, triglycerides, and β-lipoprotein. It is very effective for hyperlipidemia, atherosclerosis, coronary heart disease, angina pectoris, etc. It also has a regenerative and bactericidal effect. It has a good effect on various tissue damage and inflammation. More importantly, sea buckthorn seed oil also has a unique role of anti-cancer and anti-cancer.
How to extract seabuckthorn seed oil
Because of the special medicinal value of seabuckthorn seed oil, it is very popular in the world. At present, the extraction methods of seabuckthorn seed oil are mainly divided into three types: pressing method, n-hexane extraction method, and supercritical CO2 extraction method.
The CO2 extraction process of seabuckthorn seed oil
The pressing method is to obtain seabuckthorn seed oil by pressing seabuckthorn seeds, with a low oil yield of only 3%.
The extraction yield of the solvent method is as high as 6.0%, but the residual solvent cannot be completely removed, which affects the quality of sea buckthorn oil. In order to avoid the existence of residual toxicity, non-toxic oil extraction is used, but sea buckthorn oil cannot be separated from the oil used for extraction and can only be used in the form of a mixture, which affects the quality of sea buckthorn oil, and the yield is not high
The supercritical fluid extraction rate of sea buckthorn oil can reach 8.12%, with high active material content, no environmental pollution, good oil quality, and no solvent residues.
The supercritical CO2 extraction method mainly uses liquid CO2 to extract crushed seabuckthorn seeds in high-pressure equipment, so that the contained oil is leached out;
Then seabuckthorn seed oil and liquid CO2 are separated in a high-pressure separator to obtain seabuckthorn seed oil. The separated CO2 is a gas-liquid mixture, which is pressurized and turned into a liquid to be recycled.
Seabuckthorn seed oil obtained by this method always maintains the temperature at 50℃-60℃ during extraction, and the liquid CO is also a volatile matter, which is not easy to stay in the oil. The seabuckthorn oil obtained does not contain residual solvents, and the effective ingredients are not Damaged, the quality of seabuckthorn seed oil is very good, and the yield is about 8.12%.
The supercritical CO2 extraction method is known to be the most effective and least residual extraction method, and it is also the most advanced co2 equipment for extracting seabuckthorn seed oil.
Analyze the chemical composition
Method: Gas chromatography-mass spectrometry-computer coupled (GC-MS-DS) method was used to directly analyze the free components of sea buckthorn seed oil; the fatty acid content in the oil was determined after treatment by the hydrolysis-methylation method.
Results: The seed oil of sea buckthorn was directly injected, and unsaturated aldehydes (15.23%), vitamin E (10.46%), aromatic resin alcohols (2.55%), and sterols (27.23%) were detected.
Hydrolysis-methylation Eight kinds of fatty acids were measured, of which the relative content of unsaturated fatty acids was as high as 90%.
Conclusion: The supercritical CO2 extraction method is used to extract seabuckthorn seed oil, not only without solvent pollution but also because the chemical composition of the product is more comprehensively retained.
The direct GC-MS analysis of seabuckthorn seed oil extracted by supercritical carbon dioxide can only roughly measure the free chemical components, such as saturated and unsaturated fatty acids, aldehydes, vitamin E, and sterols.
Bound fatty acids, such as fatty acid glycerides, cannot be detected directly by sample injection due to their high boiling point and non-volatile content. Therefore, the relative percentage of each substance is for reference only.
β-tocopherol and aromatic resin alcohols have not been reported, and more unsaturated aldehydes have been detected, which may be related to the supercritical CO2 extraction process.
The content of unsaturated fatty acids is as high as nearly 90% of the fatty acids in seabuckthorn seed oil extracted by supercritical carbon dioxide, and it is rich in unsaturated aldehydes, vitamin E, aromatic resin alcohols, flute, and other biologically active substances.
These ingredients provide a basis for the antibacterial, anti-ulcer, and immune function of seabuckthorn seed oil, prevention, and treatment of cardiovascular and cerebrovascular diseases, treatment of hepatitis, and anti-cancer.
Postscript
After editing this article, I am very interested in sea buckthorn, so I ordered 2000ML of sea buckthorn juice from Xinjiang Huihua Seabuckthorn Biotechnology Co., Ltd., China; add water and honey to drink, the flavor is unique.
As for its health care effects, I think it will take some time to wait for it to discover its functional health care.
Conclusion
In this study, we investigated the supercritical CO2 extraction process and chemical composition of seabuckthorn seed oil. The results showed that the supercritical CO2 extraction was an efficient method for obtaining seabuckthorn seed oil with a high extraction yield and high-quality chemical composition. Seabuckthorn seed oil was rich in unsaturated fatty acids, especially alpha-linolenic acid, and exhibited significant antioxidant activity, which could be attributed to its high content of polyphenols, flavonoids, and carotenoids. Seabuckthorn seed oil has potential applications in the food, pharmaceutical, and cosmetic industries, and the findings of this study provide valuable information for the production of high-quality seabuckthorn seed oil.