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Students Build High-Tech Olive Oil Sensor

A team of UC Davis students built a bio-sensor machine that can detect rancid or fraudulent olive oil. From left are: James Lucas, Sarah Ritz, Simon Staley, Yeonju Song, Brian Tamsut and Lucas Murray. (Karin Higgins/UC Davis)A student team composed of some of the best and brightest young minds at the University of California, Davis, today took the grand prize in the finals of the global iGEM (International Genetically Engineered Machines) competition in Boston. The team also won the Best Policy and Practices Advanced Presentation Award.

The competition, which this year featured 245 teams from Asia, Europe, Latin America and North America, annually challenges student teams to design and build biological systems or machines and present their inventions in the international competition.

Why is this important olive oil news, you may ask? Well, it’s because this team spent several months building a high-tech, palm-sized biosensor to quickly evaluate the chemical profile of olive oil! Their creation provides a prototype for quickly and accurately detecting low-grade or adulterated olive oil and is intended to mimic the taste buds of humans and the parallel (or exceed) the human assessment process of olive oil.

Extra-virgin olive oil is flavorful and healthy, which could explain why sales of high-quality olive oil have tripled in America in the last two decades. But when you buy a bottle of extra-virgin olive oil, can you be sure the oil inside is, indeed, “extra virgin”?

Unfortunately, the answer is “no”. In fact, as much as two-thirds of the extra-virgin olive oil sold in the United States is actually much lower-grade oil, lacking the antioxidants, omega-3 fatty acids, and flavor found in true extra-virgin olive oil. So, what’s a poor consumer to do?

The team of of UC Davis students built a biosensor designed 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.

“It’s a lot of work, but it’s rewarding,” said Brian Tamsut, a sophomore majoring in biotechnology, surrounded by his teammates in the UC Davis Genome Center where their palm-sized biosensor was taking shape. “It’s especially rewarding knowing our project is practical and will solve a real, tangible problem.”

Ensuring olive oil quality is, indeed, a real concern for consumers and people throughout the olive oil industry. Shoppers pay more for extra-virgin olive oil and want to get their money’s worth. Honest olive oil producers want to keep fraudsters from passing off sub-par olive oil as the real deal, and retailers, distributors and producers want a quick, easy way to ensure olive oil quality. And it’s not just a question of fraud. 

“Even good oil can go bad,” explained Dan Flynn, executive director of the UC Davis Olive Center. “Extra-virgin olive oil has a shelf life.”

Extra virgin is the highest grade of olive oil, produced by crushing fresh olives and extracting the oil. True extra-virgin olive oil has a fruity flavor and no defects such as rancidity, the most common olive oil defect.

Rancidity is that stale taste and smell that you get when oil oxidizes over time or is exposed to too much light, heat or air. Lower-grade olive oils, produced using heat or solvents to extract the oil, lack the health benefits and flavor of high-grade olive oil.

There are olive oil standards set by the International Olive Council and the USDA, but they are voluntary. Importers, especially, can get away with mislabeling and selling a sub-par product because it’s hard to trace where and how imported olive oil is produced. Little Angel is proud to be a 100% pure Greek extra virgin olive oil that can stand up to any test of authenticity and purity!

Trained sensory scientists can distinguish fresh and high-quality from defective olive oil, but there’s no user-friendly machine that can quickly assess olive oil quality.

What does rancid olive oil look like, chemically speaking, and how do you build a device that can quickly, easily and inexpensively test for those signature chemical compounds? That was the daunting task facing the six iGEM team members, the best and brightest of the hundreds who applied to be part of the 2014 UC Davis team.

“It’s extremely complicated,” said Selina Wang, research director for the UC Davis Olive Center and one of four advisers to the 2014 iGEM team. “The chemical methods we have available now are either too crude and don’t correlate with sensory traits, or are too time-consuming and require expensive instruments. The students’ goal was to generate an affordable device to detect a comprehensive profile of signature rancidity compounds that match what we smell.”

They’re really close. Their electrochemical biosensor — shaped liked an oversized thermometer — comes complete with the computer hardware and software necessary to read rancidity levels in a single drop of oil.

“It’s not perfect, but we’re getting there,” said Aaron Cohen, a junior majoring in biomedical engineering.

Their biosensor will be best suited for producers, buyers and retailers because it’s probably too complicated in its current form to easily test olive oil quality at home. But Wang sees a day when a future generation of this technology could be built into every bottle of extra-virgin olive oil to guarantee freshness.

“That way, consumers can see at a glance whether their olive oil is starting to turn rancid,” Wang said.

In the meantime, people throughout the olive oil industry, here and abroad, could benefit from the new biosensor, which the team predicts will retail for about $125.

“UC Davis provides world-class agricultural research,” said Simon Staley, a sophomore majoring in biosystems engineering. “So it’s fitting for us to seek solutions to food quality and safety concerns.”

The UC Davis team is composed of undergraduate students Lucas Murray, Brian Tamsut, James Lucas, Sarah Ritz, Aaron Cohen and Simon Staley, with student Yeonju Song serving as an alternate or “shadow” team member.

Adapted from

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