Posts Tagged: oil

Nearly 70% of private label avocado oil rancid or mixed with other oils

Researchers identify key markers to help professional retail buyers choose authentic products

Avocado oil has become a popular choice for many people in recent years because of its heart-healthy benefits and versatility in cooking. However, 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 at the University of California, Davis, 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 U.S. and Canada with various price points. 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,” said Selina Wang, associate professor of Cooperative Extension in the Department of Food Science and Technology. She and Hilary Green, a postdoctoral researcher at UC Davis, co-authored 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 U.S. 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 said.

Avocado oil standards

Since the release of the first UC Davis study, Wang said 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 said. “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.”

Food bloggers see innovative olive oil production system in Capay Valley

More than 400 food writers have converged in Sacramento for the first International Food Bloggers Conference to be held in the California capital. The event began with an excursion for about 45 of the foodies to Capay Valley Ranches, where the focus was on production of premium extra virgin olive oil.

The writers heard about innovations in olive oil production that have allowed California producers to minimize labor costs and maximize yield and quality by establishing super-high-density orchards. Farm manager Joe Armstrong led a farm tour, explaining amendments that had to be added to the soil before planting, the configuration of the trees in hedgerows and an irrigation system that permits application of water to the trees exactly when it is needed.

A graduate of California Polytechnic State University, San Luis Obispo, Armstrong said he choose a career in agriculture precisely because of the new technologies that make the field more efficient and productive.

"That's why I have a passion for farming," Armstrong said.

Ranch owner Chris Steele, who has farmed in Capay Valley his entire life, recognized how such innovations are brought to the farm.

"We couldn't do this without the UC system," he said.

UC Cooperative Extension advisors and specialists have worked alongside farmers to adapt the new super-high-density orchard systems. The idea was conceived in Spain and introduced into California in the 1990s. Successful use of high-density olive farming requires careful variety selection; finessed pruning, fertilization and irrigation practices; and understanding the cost-and-return for adept decision-making. This month, UCCE scientists released a new cost-and-return study specifically for farmers to use when planning new olive orchards under the super-high-density planting configuration.

Students' olive-oil fraud buster wins international prize

A student team composed of some of the best and brightest young minds at UC Davis took the grand prize last week in an international competition for the high-tech biosensor they created to detect low-grade or adulterated olive oil.

The award was presented to the Aggie inventors during the finals of the three-day global iGEM (International Genetically Engineered Machines) competition in Boston. The competition, this year featuring 245 teams from Asia, Europe, Latin America and North America, challenges student teams to design and build biological systems or machines and present their inventions in the international competition.

The students had spent several months designing and building the palm-sized biosensor, which they dubbed OliView. The biosensor is equipped to quickly and easily evaluate the chemical profile of oil, providing producers, distributors, retailers and ultimately consumers with an effective, inexpensive way to ensure olive oil quality.

Verifying olive oil quality is a concern for consumers – many of whom are willing to pay higher prices for the health benefits and flavor of true, extra-virgin olive oil. And honest olive oil producers want to prevent other producers from passing off sub-par olive oil as the real deal, while retailers, distributors and producers want a quick, easy way to ensure olive oil quality.

In addition helping detect fraudulent olive oil, the students' new biosensor will also monitor for good oil that may have gone rancid with age. 

The team of undergraduate students included Lucas Murray, Brian Tamsut, James Lucas, Sarah Ritz, Aaron Cohen and Simon Staley, with Yeonju Song serving as the “shadow” or alternate team member. You can tune into Aaron Cohen's recent Nov. 6 Science Friday interview during a discussion of synthetic biology.

The full story and a brief video about the new olive-oil biosensor and this stellar team of young inventors are available at: http://news.ucdavis.edu/search/news_detail.lasso?id=11076.

Reports on olive-oil quality are available at the web site of the UC Davis Olive Center at: http://olivecenter.ucdavis.edu/research/reports.

Consumers need more information on olive oil

Olive oil is repeatedly in the news these days, but the stories often raise as many questions as they anwer:

• It’s touted as the “healthy oil." Does that hold true for cooking and eating raw?
• It adds a range of flavors to food. Just what is EVOO and should you pay more for it?
• You can choose “grassy” or “peppery” olive oil. But what does that mean?
• How can you tell if olive oils are adulterated with lesser-grade oils, or oils from entirely different plants?

A new survey, spearheaded by Dr. Selina Wang at the Olive Center at UC Davis, shows that consumers need more information about olive oil in order to make informed decisions. Consumers were asked a number of questions about olive oil. Surprisingly — or maybe not — consumers thought they know more about olive oil than they actually do. Many consumers aren’t savvy about cooking with olive oil or assessing its tastes and qualities.

Results of the survey indicate that “there are opportunities for producers to modify marketing practices to assist consumers in making better informed olive oil purchasing decisions.”

Reading the survey results will provide consumers with a lot of information about olive oil’s attributes and will help consumers make better purchasing choices.

More information about the survey:

• Read the UC Davis press release about the survey
• Read the full survey results
• UC Davis Olive Center

Other recent olive oil news stories:

• Olive oil ‘fridge test’ doesn’t reliably detect fraud, March 2013
• New olive oil testing program aims to boost quality and reliability, January 2013

How waste becomes gourmet food

I attended the Fancy Food Show in San Francisco in January and I was delighted with the offerings from local companies near UC Davis. Since I attended this vast international exhibit, I have purchased several local products that I discovered at the show. The exhibit was so large, I was only able to see half of it in a day. I met Matthieu Kohlmeyer, the French CEO and General Manager of La Tourangelle, whose walnut oils are processed 15 minutes away in Woodland.

I was also impressed with Mezzetta pasta sauces from Napa. I have purchased their olives and fire-roasted peppers for years, so why did I fail to notice their pasta sauce among the endless brands on the shelves? Unfortunately, my favorite in their line, Puttanesca, was not on the shelf at my grocer, but I found the spicy Arrabbiata, my second favorite tasting at the show. 

As I looked for the locals I looked in vain for a local grape seed oil. The Italians were selling grape seed oil at wholesale prices that were surprisingly low.  Meanwhile, I knew that grape seeds in our nearby wine regions are still largely treated as waste, just as UC Davis olives were treated before our former grounds manager Sal Genito partnered with a local olive oil company to launch a gourmet brand of oil at UC Davis.  

To my delight, Sacramento Bee Food & Wine writer Chris Macias featured WholeVine grape seed oil on the March 14 food page. Its parent company is a successful local start-up, SonomaCeuticals, Santa Rosa, who developed the process to extract the oil from local grapes.

Not surprisingly, UC Davis was involved. Sharon Shoemaker, director of the UC Davis' California Institute of Food and Agricultural Research (CIFAR), was interviewed about her role in helping SonomaCeuticals tap into campus expertise. WholeVine grape seed oil is cold pressed, allowing it to retain the natural flavors of chardonnay, zinfandel, reisling and other winegrape seeds. The flavor provides an added bonus to a naturally high smoke point and health benefits. This commands a higher price than imported oils and allows the firm to compete in this market.

Shoemaker and her program CIFAR (see-far) are champions of campus research. Since 1992, her dynamic energy has been sustained through private enterprises that pay for her business-friendly conferences and services to benefit small and large concerns. Rarely does the public see how often executives drop in to tap into UC Davis resources. This happens behind the scenes with little fanfare, except this time, when the nuances of a new product triumph came to light on the food page. All of us can now enjoy the benefits.  

Read more