Monday, December 22, 2014

Looking for virgin olive oil? Here is a tool for easy testing

Olive oil is a much valued "healthy" vegetable oil in great demand through out the world. Whether it is for its health benefits or for its characteristic flavor olive oil is widely prefered as compared to other liquid oils. All edible oils are made of a mixture of fatty acids and glycerol and the ultimate fluidity will depend on the extent of unsaturated fatty acids present in a given oil. As a thumb rule more fluid an oil is, higher can be contents of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA). Both MUFA and PUFA are highly regarded for their influence on heart health and other benefits for human beings. Good things some time come with a rider and olive oil is no exception. Because of unsaturated fatty acids, its shelf life is some what restricted as it gets rancid due to oxidation at ambient conditions. Also it attracts hordes of fraudsters to tamper with it by mixing with cheap oils. Incidentally olive oil is the costliest edible oil, the prices being 100-500% more than other vegetable oils. Extra virgin olive oil is a much coveted product made under mild processing conditions so that the rancidity level is practically undetectable and it fetches higher price compared to other grades of olive oils. Recent announcement that a simple device has been designed to confirm whether samples of olive oil are really virgin is being welcomed by the organized industry which has a stake in protecting the USP of virgin olive oil. Here is a take on this new development.

"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. "I think their project has great potential," said David Garci-Aguirre, production manager at Corto Olive Co. in Lodi. "A biosensor that provides an easy, affordable way to help ensure the quality of our olive oil could prove an incredibly useful tool for us, for retailers and especially for consumers. I see this kind of innovation really helping to get good oils into the hands of those who are trying to buy good oils."

The claim by the scholars who worked on this device needs to be independently verified because many a time scholarly research runs into problems when commercially applied.  As a biosensor is used for measuring rancidity in the oil and subsequent computation requiring electronic computing system, the claim that it could be useful to consumers may be some what far fetched and rightly the innovators admit about this limitation. It is good that they are looking further to develop a thermometer sized device amenable for use by consumers is encouraging. Rancidity is usually measured by parameters like peroxide values and other chemical paradigms which can give an approximate indication of the quality of the product but requires laboratory facilities to carry them out. Sensory tests also can differentiate between virgin olive oil and other grades but these tests are some what subjective requiring highly trained taste panelists. The above efforts in evolving a new simple and inexpensive tool for confirming the grade of olive oil are timely and relevant.


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