Chemists Offer 5-Minute Video on Why Olive Oil is 'Awesome'

A video tells us how the molecules and antioxidants in olive oil help keep you healthy, how to recognize differences between oil varieties, how to use the oil, and how to store it.

By Maja Dezulovic
Jul. 6, 2017 07:48 UTC

The American Chemical Society’s Reactions YouTube chan­nel has released a video explain­ing the chem­istry behind olive oil and why it is a good kitchen sta­ple. The video goes into how mol­e­cules and antiox­i­dants in the oil help keep you healthy, the dif­fer­ence between oil vari­eties, how to use the oil, and how to store it.

There are hun­dreds of vari­eties of olive oil, and it takes over a thou­sand olives for one liter of high-qual­ity olive oil, the video states. Olives har­vested at dif­fer­ent points in the sea­son also pro­duce dif­fer­ent fla­vors. Lower qual­ity oils are extracted using chem­i­cal sol­vents like hexane, but the best oils (like vir­gin and extra vir­gin oil) are cold pressed using only mechan­i­cal processes. Extra vir­gin olive oil has to meet high-qual­ity taste stan­dards, and have no defects due to oxi­da­tion or fer­men­ta­tion. It is the most fla­vor­ful, but also the most expen­sive of olive oil vari­eties.

Oleic acid is a major com­po­nent of olive oil which shows up as part of a larger mol­e­cule called a triglyc­eride. Sloppy har­vest­ing and extrac­tion tech­niques can lead to triglyc­erides break­ing up to form free fatty acids, which means a higher acid­ity and a lower score on the qual­ity scale.

Olive oil is also rich in monoun­sat­u­rated fatty acids, which pump up the rate at which cells pull bad cho­les­terol out of the blood­stream. It is also rich in antiox­i­dants, called plant phe­nols (like hydrox­y­ty­rosol) and vit­a­min E. The body uses these antiox­i­dants to keep free rad­i­cals (which cause cell dam­age) in check. The antiox­i­dants give olive oil its pep­pery taste.

Olive oil enhances the fla­vor of foods. Some of the taste and antiox­i­dants are lost in high tem­per­a­tures, but you can safely use olive oil in fry­ing, saute­ing and bak­ing (up to 400 degrees Fahrenheit). Extra vir­gin olive oil shines the most in cold dishes where you get more from its taste.

How the oil is stored is impor­tant. This is because olive oil does not age well. Light and heat degrade the oil over time and make it ran­cid due to increased oxi­da­tion with its con­tin­ual expo­sure to the air. This breaks down the fatty acids in the oil into per­ox­ides that decom­pose into alde­hy­des and ketones, which are respon­si­ble for unpleas­ant fla­vors and odors.

The antiox­i­dant con­tent is also reduced over time. To keep the qual­ity of the olive oil for longer, it can be pro­tected by stor­age in a dark bot­tle or stor­ing the bot­tle in a cool, dark space. Looking for a har­vest date on the bot­tle can also help to ensure fresh­ness. It is advised to use up the oil in six weeks after open­ing.

Dan Flynn from the UC Davis Olive Center says: A really good oil should have a fla­vor rem­i­nis­cent of some­thing that’s grown out in a grove, and it should have this grassy or maybe a fruity fla­vor. An oil that’s not very good would remind you more of some­thing that you’ve stored in your garage for a long time.” Flynn rec­om­mends buy­ing olive oil accord­ing to fresh­ness rather than the price tag.


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