About 70% of avocado oil is rancid or impure

"...there are still issues with purity in avocado oil and these issues extend significantly into private label oils," Selina Wang says. (Credit: Getty Images)

Nearly 70% of private label avocado oil is rancid or mixed with other oils, tests reveal.

Avocado oil has heart-healthy benefits and versatility in cooking, but not all avocado oil products on store shelves are created equal. Some products are labeled as “pure” avocado oil when they contain other oils or additives. No enforceable standards defining the chemical and physical characteristics of avocado oil exist yet.

Researchers analyzed samples of 36 private label avocado oil products and graded them based on quality and purity. Private label products are made by a third-party processor and sold under a grocery store or retailer brand label.

Their findings, published in the journal Food Control, show that 31% of the samples tested were pure, and 36% were of advertised quality. Quality refers to whether the oil is fresh or has gone bad due to aging, heat, or light exposure. For purity, researchers measured fatty acids, sterols, and other components that differentiate avocado oil from other oils.

The study included oils purchased from 19 retailers in the United States and Canada with various prices. They found that lower-priced oils were more likely to be tainted with other oils.

“We found that low-cost products indicate a higher probability for adulteration, but high cost didn’t guarantee purity or quality,” says Selina Wang, associate professor of Cooperative Extension in the food science and technology department. She and Hilary Green, a postdoctoral researcher at UC Davis, are coauthors of the paper.

Researchers also identified certain chemical markers in avocado oil that professional retail buyers can use to make more informed decisions when it comes to choosing suppliers. This way, consumers can feel confident about the products they buy.

This is the second comprehensive study conducted by UC Davis researchers on the quality of avocado oil sold in the US. The first study released in 2020 found that many of the test samples were of poor quality, mislabeled, or adulterated with other oils.

“This study demonstrates that although progress is being made in standard development since our first market study in 2020, there are still issues with purity in avocado oil and these issues extend significantly into private label oils,” Wang says.

Since the release of that first study, Wang says there’s been a coordinated effort by researchers, industry leaders, and government agencies to establish enforceable standards. The Avocado Oil Expert Group was formed in collaboration with the American Oil Chemists’ Society to discuss potential standards and future research projects.

Wang’s research group has been studying how natural factors like different types of avocados, harvest times, geographic origins, and processing methods could affect the chemical composition of avocado oil. They want to create standards that will accommodate natural variations while detecting any adulterations.

Wang hopes that the study’s findings will contribute to the establishment of standards that benefit both consumers and avocado oil producers who want to compete in a fair market.

“I’m very optimistic for the future of the avocado oil industry,” Wang says. “It’s a high-value product with high consumer demand, similar to what I saw with olive oil 10 years ago. Olive oil quality and purity have improved significantly, which is where I see avocado oil going, if we can establish fair standards and eliminate fraudulent products.”

Source: Tiffany Dobbyn for UC Davis