The Wild West of edible oils

By Stacy Kish

In This Section

April 2023

Avocadoes are having a moment. The nutritional benefits promote heart health and reduce inflammation, blood pressure, and cholesterol. Not to mention the popularity of avocado toast.

  • Avocado oil has become a very popular cooking oil due to its mild flavor, high smoke point, and nutritional profile, but a 2020 study found that the majority of avocado oil on store shelves is oxidized, mislabeled, or adulterated with lower-quality vegetable oils.
  • The Codex Committee on Fats and Oils (CCFO), an international organization that sets standards for oils and fats, began the process of determining a standard for avocado oil in 2017.
  • A team of researchers in California found that avocado oil can be differentiated from other high oleic vegetable oils using the profile of specific fatty acids ((C18:1 (n-7) and C18:1 (n-9)) and sterols (stigmasterol, clerosterol, and beta sitosterol).

Despite the rise in consumer interest, there are no standards to define the chemical and physical characteristics of avocado oil. Without an internationally defined standard, consumers are left vulnerable to adulterated or fraudulent avocado oil in the marketplace.

"Currently selling and buying avocado oil is like playing a boardgame with no rules," said Selina Wang, department vice-chair and associate professor of Cooperative Extension in the Department of Food Science and Technology at the University of California, Davis. "With no enforceable standards in place, cheaters win and honest players get taken advantage of."


An avocado’s fleshy green fruit is rich with lipids. Past research has shown that the level of fatty acids remains fairly constant as the fruit matures. The oil is typically pressed from either the pulpy, green flesh or the entire avocado ( In the United States, the Hass cultivar is the most common variety grown to eat and for oil.

Past work has shown that the maturity of the fruit and temperature during pressing influence the amount of oil obtained. The fresh-pressed oil is a pale green color and has a buttery, grassy flavor that is reminiscent of mushrooms. Often, avocados destined for oil production have been rejected from fresh fruit sales, but over ripened fruit can lead to discolored oil. Producers walk a fine line when deciding what fruit to press.

a figure paste made from avocado flesh in a lab scale malaxer where the oil droplets start to coalescence before oil extractionOpen photo in lightbox
FIG. 1. Paste made from avocado flesh in a lab-scale malaxer where the oil droplets start to coalescence before oil extraction. Credit: John Almazan

Since avocados contain chlorophyll, which is photosensitive, the oil is particularly vulnerable to light that can catalyze oxidation. For this reason, it is commonly stored in clean, dark-colored glass bottles or stainless steel containers.

Avocado oil is popular for cooking, because it has a mild flavor and a high smoke point. It has a similar fat profile to olive oil (∼20% saturated fat, ∼70% monounsaturated fatty acids, and ∼10% polyunsaturated fatty acid) and is a common addition to the Mediterranean diet. The oil is high in omega-9 fatty acid, which is one of the polyunsaturated fatty acids associated with heart health and is rich in alpha-tocopherol, a powerful antioxidant that prevents the formation of damaging free radicals in the body. It is rich in the antioxidant lutein, which supports eye health and reduces inflammation associated with arthritis. Avocado oil also helps the body absorb fat-soluble vitamins, like A, D, E, and K.

With all of these health benefits, it is no wonder that consumer demand for this oil is on the rise. The question of the moment is: What is actually in the bottles on the store shelves?

a figure avocado paste after malaxing containing a mixture of free oil and vegetationOpen photo in lightbox
FIG. 2. Avocado paste after malaxing, containing a mixture of free oil and vegetation, water and solids. Credit: John Almazan

"Our results show that there is a problem that needs attention," says Wang. "Consumers seeking the health benefits of avocado oil deserve to get what they think they are buying."


The Consumer Protection Act (Act 68 of 2008) states that consumers have a right to high-quality products that are not falsely marketed or misrepresented. In 2017, the CODEX Committee on Fats and Oils (CCFO), an international organization that develops worldwide standards, codes of practices, and guidelines for fats and oils of animal, vegetable, and marine origin, began the process of standardizing the definition of avocado oil ( This change is necessary because a recent study shows that much of the avocado oil currently on the market is not from the pulpy, green fruit.

In 2020, Wang led a team of researchers at UC Davis on the first large-scale examination of commercially available avocado oil. The study consisted of 22 samples obtained from six stores and two online outlets ( They compared the samples to the proposed standards from CODEX and researchers in New Zealand to evaluate quality and purity. Their results set off a ripple across the industry.

The team found that the majority (82%) of the avocado oil in the study was stale or adulterated with other vegetable oils. Of the 22 samples collected, 15 were oxidized, which robs the oil of its flavor and health benefits. Some bottles labeled ‘pure’ or ‘extra virgin’ avocado oil were in fact mixtures of the less expensive, yet healthful soybean, safflower, and sunflower oils.

These findings illustrate the need for standards to protect consumers and the growing industry from fraudulent products. Most producers can agree that standards are essential, but how to draw those standards is the looming question.

"Based on our ten years of experience working on olive oil, a fair standard would be important for the avocado industry so it can continue to grow," Wang said. "Working together with the industry, we can establish standards and make sure customers are getting high-quality, authentic avocado oil and the companies are competing on a level playing field."


The CCFO defines a standard by finding a range of chemical and physical characteristics—like the amount of fatty acids, sterols, and tocopherols—to establish parameters for authentic oil from the avocados collected from member countries interested in participating. According to Wang, it will be difficult to establish a standard for avocado oil without a representative sampling of fruit from across the growing regions of the world. She worries that no matter how well thought out and meaningful, without a proper representation of samples any established standard could be excluding authentic avocado oil.

a figure box and whisker plot showing the percent cis vaccenic acidOpen photo in lightbox
FIG. 3. Box and whisker plot showing the percent cis-vaccenic acid (C18:1 n-7) in avocado oil compared to other potential adulterant oils. HO = high oleic. Source: Green, H.S. and Wang, S.C., Food Chem Advances, 1, 100107, 2022.

"It keeps me up at night," says Wang. "To establish limits, a good standard has to be inclusive of all of the natural variation that results from climate, the avocado cultivar, and the region where it was grown."

Wang and her team began the process of evaluating the proposed CODEX purity standards for avocado oil in a paper published in January ( She included data obtained from five avocado growing regions to evaluate the natural range of chemical compounds in avocado oil. The fatty acids in avocado oil include saturated fatty acids (palmitic (16:0) and stearic acids (18:0)), monounsaturated fatty acids (palmitoleic (16:1) and oleic acids (18:1)), and polyunsaturated fatty acids (linolenic (18:2) and linoleic acids (18:3)). Triglycerides increase as the fruit matures. To find the right range for each fatty acid in avocado oil to differentiate it from high oleic oils, the team focused on the sum of oleic acid (C18:1 (n-9)) and its isomer (C18:1 (n-7)) ( Existing analytical methods can quickly determine the concentration of these fatty acids in a sample.

The data from Wang’s lab show the concentration of the oleic acid isomer is commonly between 5.5 and 7 for avocado oil. This concentration falls below 4 for other high oleic oils, like safflower, sunflower, canola, and soybean oil. Comparing the ratio of oleic acid to its isomer (n-9/n-7), pure avocado oil produces values between 5.7 and 13, vegetable oils are closer to 100. To help characterize levels of adulteration, Wang suggests setting the proposed acceptable n-9/n-7 range to between 6 and 11.5 for avocado oil to ensure 75% of the sample is pure. This range may change slightly with more authentic samples from other regions to accommodate natural variances.

In addition to the fatty acid profile, Wang and her team examined two other chemical compounds to fingerprint avocado oil. The analytical technique to identify sterols, a type of lipid that helps maintain the plant’s cell membrane, is complex but provides valuable information to identify adulteration. Stigmasterol is practically non-existent in pure avocado oil, but it is a common sterol in adulterating vegetable oils. Conversely, clerosterol and beta sitosterol occur at low concentrations in other vegetable oils but are enriched in avocado oil (clerosterol ∼1.47 to 3.49% of total sterols and beta sitosterol ∼ 81.71–85.87% of total sterols).

Tocopherols, which are antioxidants naturally occurring in avocado oil, provide an additional path to verify avocado oil purity. The draft CCFO avocado oil standard proposed a range from 50 to 450 mg/kg for alpha tocopherol, 10 to 20 mg/kg for gamma tocopherol, and non-detectable to 10 mg/kg for delta tocopherol. Wang’s team found oil pressed directly from the fleshy, green fruit fell below 200 mg/kg for alpha tocopherol and were non-detectable for the remaining tocopherol varieties. For oil pressed from the whole fruit, the values obtained were close to the top values proposed by CCFO.

Past studies on olive oil suggest that the process of refining an oil can remove tocopherols from the composition. This factor along with how the fruit was pressed can affect the overall concentration of tocopherols, which may require additional scrutiny when developing a tocopherol range for defining avocado oil purity.


Many countries are in the avocado oil market, including Mexico, South Africa, Kenya, Brazil, Peru, New Zealand, and the United States. Most oil sold in the US is refined, or processed with heat or chemicals to remove flaws. Other countries, like New Zealand, only sell virgin or extra virgin oils, which are pressed from healthy fruit without heat or solvent.

While virgin and extra virgin oils contain a higher concentration of antioxidants that boost the health benefits (, the draft standard for avocado oil is only being defined for the refined variety. Establishing a separate standard for virgin and extra virgin avocado oil is currently an issue under discussion.

Navigating avocado oil as a consumer

It is safe to say that with no standard in place, purchasing a bottle of avocado oil at the super market has turned into a game of roulette. For this reason, Wang has a few tips that consumers can follow as they browse the store shelves.

She recommends that consumers check the date of harvest on the bottle’s label to ensure maximum freshness. If the harvest date is not available, Wang suggests selecting an oil that has the longest time before the ‘best before’ date. Remember, all oil, regardless of quality, will oxidize over time. During rancidification, avocado oil takes on an odor similar to Play-Doh™. To preserve the oil, purchase a bottle that will be finished by the ‘best before’ date and store the bottle away from light and heat. In other words, do not keep your oil next to the stove top. Wang also suggests buying avocado oil packaged in dark glass rather than clear plastic to reduce the impact from oxidation.

navigating avocado oil as a consumerOpen photo in lightbox

"We need quality criteria to differentiate virgin, refined and crude avocado oil," says Wang. "But to eliminate adulterations, we need purity criteria such as fatty acids and sterols composition which is very similar among different types of avocado oil."

The standards are not codified and are meant to be revised and updated when changes occur. The CCFO agreed to approve the draft revision to include avocado oil at the meeting in 2021, and forwarded it to the CODEX Alimentarius Commission, which accepted the new draft standard with the exception of several provisions that the committee continues to work through. The CCFO is currently collecting more data to update those provisions, which will be further evaluated for their inclusion in the revision at the next meeting in 2023.

According to Wang, the avocado industry could address the purity question by taking a page from their olive oil counterparts and begin the process of developing practices for self-regulation. This step in unity can regain and maintain the trust of their customer base. Through self-regulation, the avocado oil producers can agree on certain verifiable characteristics and third-party testing can be used to ensure purity and quality of their product while the world awaits the final CCFO standard. A certified seal on an avocado oil’s label would confirm third-party verification and amplify consumer confidence.

"Let’s make sure avocado oil is made from avocados," Wang says. "Honest producers want their customers to know they care about quality and authenticity, and they have a brand that they can trust."

Wang and her team will continue to develop the techniques and refine the limits in the standards that validate the quality and purity of avocado oil, but she stresses the need for more research to understand how fruit characteristics, such as cultivar, harvest time, and post-harvest processing affect oil yield, chemical composition, and shelf life for oil produced around the world. Wang also welcomes suggestions from and collaborations with oil chemists, especially when it comes to developing rapid and reliable techniques to check for adulteration.

About the Author

Stacy Kish is a science writer for INFORM and other media outlets. She can be contacted at

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