What Makes Olive Oil Peppery?
The unique peppery sensation of high-quality olive oil is a question mark that’s been lingering in my brain for some time. Not due to its peppery character, rather, the way in which it seems to evade detection on the tongue and walls of the mouth. The pepperiness of olive oil can feel like someone hurling black peppercorns directly at the back of one’s throat.
So today we shall be diving into not just what makes olive oil peppery, but also why olive oil’s peppery character feels unique amongst other spicy and pungent oral sensations. The discoveries offer fascinating insights into not just olive oil, but also how we experience the mouth sensations of other food and drinks – even whisky and wine.
What Makes Olive Oil Peppery?
The secret sting of olive oil lies in a single phenolic compound called oleocanthal, a natural anti‑inflammatory agent that gives extra‑virgin olive oil (EVOO) its aforementioned characteristic peppery sensation at the back of the throat. While most people think of olive oil simply as a heart‑healthy-tasty fat, scientific investigations have revealed that oleocanthal has remarkable characteristics.
Anti-inflammatory:
Oleocanthal acts similarly to the drug ibuprofen in how it inhibits inflammation pathways (specifically COX-1 and COX-2 enzymes).
Antioxidant:
It helps neutralize harmful free radicals.
Potential Health Benefits:
Research links oleocanthal with reduced inflammation, potential protection against neurodegenerative diseases, and anti-cancer effects — though human clinical evidence is still developing.
Indicator of Fresh, High-Quality EVOO:
The more noticeable the peppery “burn,” the more oleocanthal the oil likely contains.
Oleocanthal is present in freshly pressed EVOO at concentrations that vary with cultivar and processing, typically ranging from 18 to 154 mg kg⁻¹. Early anecdotal reports described a stinging sensation felt only at the back of the throat after tasting certain oils. Cicerale et al (2009) quantified this irritation using a general Labeled Magnitude Scale (gLMS), a psychophysical tool used primarily in sensory and taste research to measure the perceived intensity of a stimulus. They found that participants perceived peak irritation fifteen seconds after exposure, with the sensation persisting for more than three minutes.
Why Does Olive Oil Burn My Throat?
The peppery irritation of EVOO has been localised to the oropharynx (the part of the throat behind the mouth and nasal cavity) and has shown far less intensity in the anterior (front) oral cavity. In a further study, Peyrot‑des Gachons et al. (2011) demonstrated that oleocanthal selectively activates the TRPA1 channel in both rat trigeminal neurons and human embryonic kidney cells engineered to express human TRPA1. These receptors are also sensitive to a mustard oil compound called AITC.
In contrast, it has negligible effects on other TRP channels such as TRPV1, TRPV2, TRPV3, and TRPV4. TRPV1 receptors, aka trip-vee-one, are the ones we commonly associate with pungency. They are activated by capsaicin (chilli peppers), piperine (peppercorns), along with other burning sensations such as ginger and cloves. It would be natural to assume that the peppery effect of oleocanthal works through the same pathways as these, but as it seems, it’s quite different.
Analysis has revealed a dense population of TRPA1 receptors in the layer of cells that line the pharynx (pharyngeal epithelium) but virtually none in the fungiform papillae of the front two-thirds of the tongue, which contain taste buds. This anatomical distribution explains why the irritation is felt almost exclusively in the throat.
Two complementary mechanisms account for the spatial restriction of oleocanthal’s tingle. First, the limited expression of TRPA1 in the front of the tongue means that even if the compound reaches that region, there are few receptors to trigger a sensation.
Second, oleocanthal activates TRPA1 receptors through a mechanism that does not depend on the normal pathway. Most irritants (like the mustard oil compound AITC) activate TRPA1 by chemically modifying certain amino acids at the binding site called cysteines. These cysteines act like the receptor’s activation buttons. When the researchers mutated these cysteines, AITC from mustard oil could no longer activate the TRPA1 receptors. But oleocanthal still activated TRPA1 strongly, meaning it must bind somewhere else and through a different pathway.
What Are The Wider Ramifications?
The fact that oleocanthal’s chemesthetic signal is amplified where TRPA1 receptors are abundant, while remaining muted elsewhere, is important for understanding the unique properties of olive oil. However, such knowledge has meaning beyond high quality oils because as it turns out, TRPA1 receptors are activated by a wide range of agonists.
I have already mentioned allyl isothiocyanate (AITC), present in mustard oil and wasabi too. But also there are cinnamaldehyde (cinnamon), allicin (garlic), acrolein (cigarette smoke), and interestingly ibuprofen too (Beauchamp et al, 2005). Plus a host of endogenous agonists which are produced inside the body during inflammation, oxidative stress, or ischemia (insufficient blood flow to a tissue, organ, or part of the body) (Bessac et al, 2008).
For those in the drinks trade, it raises an interesting question around how drinks or samples are assessed. For obvious practical reasons, it’s commonplace to spit a sample following swilling or ‘chewing’ in the mouth. But this may leave certain sensory properties such as TRPA1 activation undetected, potentially missing oral sensations that will be detected by the end user when the product is consumed.
The Next Chapter
Such research highlights how much more there is to understand when it comes to flavour perception. It demonstrates how little we actually know about the most important everyday experiences.
Looking ahead, further research may uncover additional compounds that activate TRPA1 receptors. This has implications for botanicals, distilling, wine-making, brewing, gastronomy, and micro‑encapsulation techniques for controlled release. Plus also for the increasing number of no-and-low products, many of which attempt to replicate burning and pungent mouthfeel sensations in the absence of alcohol. Until then, at least you now understand what makes olive oil peppery, and why it hits you in the back of the throat.
References
Cicerale, S., Breslin, P. A. S., Beauchamp, G. K., & Keast, R. S. J. (2009). Sensory Characterization of the Irritant Properties of Oleocanthal, a Natural Anti‑Inflammatory Agent in Extra Virgin Olive Oils. Chemical Senses. DOI:10.1093/chemse/bjp006.
Beauchamp, G. K., Keast, R. S., Morel, D., Lin, J., Pika, J., Han, Q., Lee, C. H., & Smith, A. B. (2005). Phytochemistry: ibuprofen‑like activity in extra‑virgin olive oil. Nature. https://www.nature.com/articles/437045a
Peyrot‑des Gachons, C., Uchida, K., Bryant, B., Shima, A., Sperry, J. B., et al. (2011). Unusual Pungency from Extra‑Virgin Olive Oil Is Attributable to Restricted Spatial Expression of the Receptor of Oleocanthal. Journal of Neuroscience, 31(3), 999‑1009. DOI:10.1523/JNEUROSCI.1374‑10.2011.
Bessac, B. F., & Jordt, S.-E. (2008). The transient receptor potential channel TRPA1: From gene to pathophysiology. Journal of General Physiology. https://doi.org/10.1085/jgp.200709906