When we talk about extra virgin olive oil, much of the conversation naturally centers on its fat.
And for good reason.
Olive oil is primarily composed of triglycerides, and its fatty-acid profile is naturally high in oleic acid, a monounsaturated fatty acid that contributes to olive oil's stability and nutritional characteristics.
But there's another, much smaller part of EVOO that researchers find particularly fascinating.
These are often called minor compounds because they make up only a small percentage of the oil.
“Minor,” however, doesn't mean unimportant.
These compounds can influence an EVOO's flavor, aroma, bitterness, pungency, oxidative stability and biological activity.
Biophenols
Biophenols are probably the best-known group of minor compounds in extra virgin olive oil.
Rather than being one substance, the term describes a family of naturally occurring phenolic compounds.
These include compounds such as:
- Hydroxytyrosol
- Tyrosol
- Oleocanthal
- Oleacein
- Compounds derived from oleuropein and ligstroside
Researchers study these compounds extensively because of their antioxidant properties and their potential effects on inflammation, oxidative stress and other biological processes.
Biophenols also matter before EVOO ever reaches your plate.
They help protect the oil itself against oxidation.
And if you've ever tasted a fresh EVOO with noticeable bitterness or a peppery sensation in the back of your throat, you've experienced some of the sensory characteristics associated with these compounds.
That bitterness and pungency aren't defects.
In a well-made EVOO, they're considered positive sensory attributes.
Tocopherols — Including Vitamin E
Extra virgin olive oil also naturally contains tocopherols, a family of fat-soluble compounds with antioxidant activity.
The most prominent is alpha-tocopherol, the biologically active form of vitamin E.
Tocopherols help protect lipids against oxidation, which makes them relevant both nutritionally and to the stability of the oil itself.
This is where that old standalone article on alpha-tocopherol fits much better.
Vitamin E is interesting—but it makes more sense as one component of EVOO's larger chemistry story than as an entire article by itself.
Squalene
Another fascinating minor component is squalene.
Squalene is a naturally occurring hydrocarbon found in plants, animals and humans, but olive oil is particularly notable among common dietary oils for its squalene content.
Researchers continue to investigate squalene for a variety of potential biological activities.
One area of research we've discussed separately involves its interaction with immune cells associated with inflammation and tissue repair.
Again, that doesn't mean consuming olive oil has been proven to heal wounds or treat inflammatory disease.
It means scientists have identified another naturally occurring component of virgin olive oil that warrants further investigation.
Sterols
Olive oil also contains plant sterols, or phytosterols.
One of the primary sterols found in olive oil is β-sitosterol.
Phytosterols are structurally similar to cholesterol and have been widely studied because they can interfere with cholesterol absorption in the digestive system.
Sterol composition is interesting for another reason, too.
The particular sterol profile of an olive oil can provide information useful in authenticating the oil and detecting adulteration.
So some of these compounds aren't only interesting from a nutritional perspective—they can also help scientists determine whether what's in the bottle is actually olive oil.
Pigments
The beautiful colors we see in olive oil come partly from naturally occurring pigments.
These include chlorophylls and carotenoids, such as β-carotene.
But here's an important olive-oil lesson:
Color is not an indication of quality.
Extra virgin olive oil can range from brilliant green to golden yellow depending on olive variety, ripeness, growing conditions and other factors.
That's one reason professional olive-oil tasting is traditionally performed using colored tasting glasses that prevent the taster from judging the oil based on appearance.
Other Minor Compounds
And we're still not finished.
Virgin olive oil contains numerous additional compounds in relatively small quantities, including:
- Triterpenic acids
- Triterpenic alcohols
- Phospholipids
- Diglycerides
- Volatile compounds
Some contribute to flavor and aroma.
Others provide information about the oil's chemistry, condition or processing.
And many remain subjects of ongoing research.
Why Does Extra Virgin Matter?
This is an important distinction.
Refining changes olive oil.
Extra virgin olive oil is produced through mechanical methods without the refining processes used to produce refined olive oil.
Because of that minimal processing, EVOO retains far more of the naturally occurring compounds responsible for its distinctive flavors, aromas and other characteristics.
That's one reason extra virgin olive oil isn't simply another source of monounsaturated fat.
Its fatty-acid composition is important—but it isn't the whole story.
Why We Look at Biophenols
When you look at the chemistry information for our EVOOs, you'll see a Biophenol value.
That number gives us information about the total concentration of a broad group of phenolic compounds in the oil.
It doesn't tell us exactly how much oleocanthal, tyrosol, hydroxytyrosol or every other individual compound is present.
And a higher number doesn't automatically mean an oil is “better.”
Olive variety, growing conditions, harvest timing and many other factors influence an EVOO's chemistry and flavor.
That's why we look at the complete picture.
More Than One Number
This is really the larger lesson of olive-oil chemistry.
It's tempting to find one impressive number and use it to judge an EVOO.
Biophenols. Oleic Acid. FFA.
But no single measurement tells you everything about an oil.
That's why the chemistry information we provide includes:
Biophenols, FFA, Oleic Acid, Peroxide Value, PPP and DAGs.
Each measurement tells us something different.
And beyond those measurements are dozens of naturally occurring minor compounds that researchers continue to investigate.
The Takeaway
Extra virgin olive oil is primarily fat—but calling it simply a “healthy fat” leaves out a fascinating part of the story.
EVOO also contains naturally occurring biophenols, tocopherols, squalene, sterols, pigments and numerous other minor compounds.
They may exist in relatively small quantities, but they help shape an oil's flavor, aroma, stability and chemistry.
And they're one of the reasons scientists continue to study extra virgin olive oil as something much more complex than a bottle of monounsaturated fat.
Sometimes the smallest components are among the most interesting.
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