Posts Tagged: Olive oil

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

New findings on benefits of “biofactors” in food

Can what we eat help fix what ails us? Research increasingly suggests the answer is “yes.” Many foods contain biofactors — biologically active compounds — that may prevent and treat illnesses including asthma, diabetes and heart disease, according to new studies from the UC Davis Center for Health and Nutrition Research (CHNR).

The upcoming July-September California Agriculture journal (to be posted by July 11) reports UC research into plant compounds (phytochemicals) that can help prevent or treat disease. The findings stem from pilot projects at the center, as well as other UC research. Articles focus on how micronutrients, biofactors and phytochemicals (plant compounds) can help reduce the risk of chronic diseases.

Biofactors are compounds in our food that affect us at the biochemical level and may ultimately benefit our health. For example, the omega-3 fatty acids in foods such as walnuts, flax seeds, kale and salmon may protect against a range of diseases associated with inflammation, including asthma and the hypertension-related inflammation that can damage kidneys. CHNR research suggests that omega-3 fatty acids could reduce asthma symptoms as well as kidney damage.

Phytochemicals and health. Epidemiological studies link particular diets to less risk of chronic diseases. Notably, the traditional Mediterranean diet — mostly vegetables, fruits and whole grains, with moderate amounts of nuts, olive oil and red wine — is associated with lower rates of heart disease, cancer, and Parkinson's and Alzheimer's diseases. However, it has yet to be firmly established that specific phytochemicals in our diets can protect against diseases. Nutritionists therefore advise eating a wide variety of plant-based foods rather than taking supplements.

That said, a number of phytochemicals do show promise in protecting against and even treating chronic diseases. For example, research shows that soybeans contain estrogen-like compounds called isoflavones that may protect against heart disease, and that compounds in olive oil and red wine may protect against heart disease and diabetes.

Mitochondrial nutrients and aging. The Mediterranean diet is rich in plant compounds that boost mitochondria (organelles in our cells that convert glucose and other nutrients into energy) and so are known as mitochondrial nutrients. When mitochondria are scarce or have genetic defects that keep them from working properly, this can generate toxic metabolites and damaging free radicals.

“Mitochondria are central to aging,” says UC Irvine aging expert Edward Sharman. “Improving their function may modulate or delay the onset of diseases related to aging, such as type 2 diabetes and age-related macular degeneration.” Mitochondrial dysfunction also plays a key role in chronic illnesses such as heart disease, type 2 diabetes and inflammatory diseases such as arthritis.

One of the most promising mitochondrial nutrients is hydroxytyrosol, which is abundant in the extra-virgin olive oil that provides most of the fat in the traditional Mediterranean diet. Moreover, the red wine that is integral to the Mediterranean diet also induces the body to produce more hydroxytyrosol.

A new essential nutrient? Another promising mitochondrial nutrient is pyrroloquinoline quinone (PQQ), which was first found in nitrogen-fixing soil bacteria and is now known to be ubiquitous.

“We’re exposed to PQQ all the time at low levels,” says CHNR co-director Robert Rucker, a UC Davis nutrition professor. “It can be derived from amino acids found in stellar dust, and stellar dust is what the earth is made of.”

While Escherichia coli and other common gut bacteria do not make PQQ, the soil bacteria provide it to the plants in our diet. Good sources include fermented soybeans, wine, tea and cocoa.

Animal studies show that PQQ affects health markedly. Rucker and his colleagues found that depriving rats of PQQ compromised their immune systems, and retarded their growth and reproductive rates. In contrast, restoring PQQ to their diets reversed these effects and returned them to good health. Moreover, PQQ stimulated nerve growth and counteracted aging in cultured cells.

Rucker and his colleagues found that, like hydroxytyrosol, PQQ increases the number of mitochondria in cells. “It’s also an extremely good antioxidant and anti-inflammatory agent,” he says.

Personalized medicine. Understanding what biofactors do in our bodies could ultimately lead to personalized medicine, where nutrition-based treatments are tailored to the particulars of each person’s biochemistry. This individual variation at the biochemical level may help explain the inconsistent outcomes of research on omega-3 fatty acids and inflammation.

“The studies are mixed,” says UC Davis pulmonologist Nicolas Kenyon. “Some have shown little effect and others have shown that omega-3 fatty acids can reduce arthritis and inflammation in blood vessels.”

Asthma can be caused by multiple biochemical pathways, which are series of chemical reactions in our cells that metabolize compounds into other products. One pathway leading to asthma may be counteracted by the omega-3 fatty acids in fish oil, and this pathway may be more active in some patients than in others. To identify those likely to benefit from omega-3 fatty acid treatment, Kenyon and his collaborators are genotyping asthma patients.

This genotyping is targeted to DNA sequences associated with asthma and so is not comprehensive.

“Some people are nervous about genome-wide analysis, which is scary because none of us is perfect,” Kenyon says. “But people are more interested when the focus is specific screening that could increase their chances of treatment.”

Last call for olio nuovo

I’m slow on the artisan EVOO wave. In December, after proofreading the new issue of California Agriculture - Growing Bigger, Better: Artisan Olive Oil Comes of Age, I purchased a bottle for my partner and the next day heard a TV comedian joke about people buying $60 bottles of olive oil for holidays gifts. (Then I felt cheap — I hadn’t spent that much!)

But the tall thin black bottle of December’s New Oil from Katz and Company, near Napa, was so fabulous I decided to start learning the extra virgin olive oil (EVOO) lexicon. Did I know for sure whether it was grassy, buttery, peppery or pungent? It certainly was green. Albert Katz this week told me why: “That’s the chlorophyll in the oil; it’s at its height in olio nuovo,” he said.

When the earliest still-green olives are crushed in November, a strong odor of fresh green fills the mill, he explained. The crush smells like fresh artichoke, even parsley, but most predominantly like grass. Katz has been in the business so long that when he catches a whiff of mown grass he looks around to see whether someone is crushing olives nearby.

Darn it, though, Katz sells their olio nuovo only in December, so it’s over. The limited production and short window of sales for olio nuovo, celebrating the first crush, is a tradition in all the major olive-growing regions of the world, including northern Italy, where the name originates. The oil is always unfiltered, cloudy, and as bold as it’s ever going to be. Katz calls it “the pungency of youth.”

This week sees the very end of the season. McEvoy Ranch has bottles of their olio nuovo for sale at their San Francisco Ferry Building store and online through this weekend (February 6). The McEvoy olio nuovo is green, robust, and peppery — peppery means it has a little burn in the throat, which is a desirable quality. (Bitter is a different matter; it’s tasted on the tongue.) Like all olio nuovo, the McEvoy new oil has sediment in the bottom of the bottle, and it has an unctuous quality, a little pleasantly thick and earthy in the mouth.

With the end of the olio nuovo season comes the release of the oils that have been stored for two months; they are already changing — more mellow, more golden — and the sediment will stay in the storage tanks. As they age through spring and summer, they’ll taste more buttery.

Climate affects the taste of oil. “Terroir” is what the environmental factors are called, explain Paul Vossen and Alexandra Kicenik Devarenne in the California Agriculture article on sensory qualities of olive oils.  Katz tastes some roundness and softness in his oil this year, from the cool summer and late harvest.

Different varieties of olive trees produce markedly different aroma compounds. Tuscan varieties, grown by both Katz and McEvoy Ranch, have robust aroma profiles (full-bodied, pungent, complex). A few stores down from McEvoy at the San Francisco Ferry Building, Stonehouse sells its milder EVOO, pressed from Spanish olive oil varieties Mission, Manzanillo, Sevillano, Ascolano and Arbequina. The Stonehouse oil isn’t spicy; it doesn’t burn the throat.

Last week, Katz released its main oils for 2011: Chef’s Pick Organic Extra Virgin and Rock Hill Ranch Extra Virgin. Rock Hill doesn’t taste like the olio nuovo, because a significant proportion of the olives in it are Taggiasca, and they weren’t harvested until after the olio nuovo was made. Chef’s Pick, though, has the same profile, Katz says. Now I know a little of the language, I think I’m going to investigate further and buy a bottle before it sells out. If I wait until summer, I’m told the green will be gone and the grassiness turned more herbal.

For more information on tasting olive oils, check out the UC Davis Olive Center; in August, they have introductory and advanced seminars on sensory evaluation of olive oil.

Paul Vossen is a UC Cooperative Extension farm advisor and expert on olive oil processing tasting; watch his video on tasting here.

Alexandra Kicenik Devarenne showed Sacramento Bee reporter Gina Kim in this video how to taste oil and recognize fustiness.

The California Olive Oil Council website lists farm tours and tasting rooms.

The Olive Oil Times has an archive of articles on tasting, including one on recognizing rancidity.

'Extra virgin' olive oil: What is it and why does it matter?

Dipping fresh bread into olive oil has become a popular alternative to coating it with butter. Olive oil consists of 85 percent unsaturated fats, and when substituted for saturated fat in the diet can promote ”good” cholesterol (high density lipoprotein or HDL), reducing risk of coronary artery disease.

Some olive oils are more beneficial than others. "Extra virgin" olive oil (EVOO), for instance, is extracted from the olive fruit without using heat or chemical solvents. This mechanical process retains the highest amount of natural “phenolic compounds” — antioxidants and anti-inflammatory agents. Such compounds both retard oxidation in the olive oil (keeping it fresh and preventing rancidity) and confer health benefits.

Miller's diagram (above) depicts the fatty acid content of olive oil. PUFA is polyunsaturated fatty acids.

 

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"Antioxidants combat cell and tissue damage due to oxidation, and anti-inflammatory agents reduce inflammation throughout the body. Inflammation can lead to an array of diseases (arthritis, coronary artery disease and more),” said Amy Myrdal Miller, registered dietitian and a program director at The Culinary Institute of America.

When oils are 'refined,' heat or chemical solvents strip away phenolic compounds; the result is often a bland flavor. Mechanically extracted "extra-virgin" oils retain aromatic components.  Pungent, peppery and sometimes bitter notes signal that an oil contains phenolics.

The growth of premium olive oil production in California has its roots in 1997, when UC Cooperative Extension Sonoma County Advisor Paul Vossen started the first olive oil taste panel in California to help producers improve oil quality using sensory analysis. (See the January 2011 California Agriculture.)

When it comes to detecting positive and negative attributes of olive oil, human tasters are superior to current chemical analytical methods. Standards to define "extra-virgin" and other grades of oil include both sensory and laboratory measures. The International Olive Council's (IOC) narrow definition specifies that EVOO must show no evidence of heat or chemical solvents. It must have zero median "defects" (as judged by trained taste panels) and more than zero median fruitiness. It must meet requirements for low levels of free fatty acids (too many of these signal degradation) and peroxide levels (a sign of oxidation).

This definition has been adopted by the U.S. Department of Agriculture (USDA) and the states of California, Connecticut and Oregon. Beginning on Oct. 24 of 2010, it became part of new USDA standards for olive oil labeling, which also define "U.S. Virgin,"  "U.S. Refined" and other grades.  Although the standards are voluntary, any manufacturer using this terminology on its label could be held to truth-in-labeling laws.

While the ultimate impact of the new USDA standards will take time, consumers can learn to identify flavor attributes of California olive oils by participating in tastings at vendors that feature artisan products. Also, the

California Olive Oil Council awards an extra-virgin certification seal to member oils that are defect-free.

However, the array of olive oils now available at supermarkets can be daunting, and "extra virgin" on the label can be misleading. The UC Davis Olive Center reported in July 2010 that their samples from Sacramento, San Francisco and Los Angeles supermarkets revealed 69 percent of imported EVOO and 10 percent of California olive oil samples labeled as EVOO failed to meet International Olive Council (IOC)/USDA sensory standards for extra virgin olive oil.

Once you identify your favorite olive oil, it should be stored in a cool, dark environment, like a kitchen cabinet removed from the stove, according to Alexandra Vicenik Devarenne, freelance olive oil consultant in Sonoma County. Fluctuations in temperature and light affect the integrity of the health-promoting phenols in extra virgin olive oil.

“When people find out about phenolics and the effects of heat on olive oil, they may question whether it is safe and okay to cook with extra virgin olive oil,” she says. “The heat will destroy some of the health-promoting phenols in the oil, which will change the flavor. The longer the oil is exposed to heat, and the higher the heat, the more phenols will be destroyed.

“However, sautéing in extra virgin olive oil for 5 to 10 minutes over medium heat will have minimal effects on phenols and flavor.”

 

See more tips on storing and cooking with olive oil.

 

 

 

 

 

 

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