When you pour extra virgin olive oil (EVOO) into a dish, the experience begins before the first taste. Freshly cut grass, green apple, tomato leaf, almond, artichoke - these aromas define the personality of high-quality olive oil. They are the reason chefs, producers, and consumers treasure it.... but what happens to that aroma after the bottle is opened?

A study from the University of Naples provides a fascinating answer: polyphenols - best known for their health benefits - also play a crucial role in protecting olive oil’s aroma during storage and household use.

Aroma: The Soul of Extra Virgin Olive Oil

Extra virgin olive oil contains dozens of volatile aromatic compounds. These are delicate molecules responsible for the sensory notes associated with fresh olives and Mediterranean landscapes.

Key aroma descriptors commonly found in EVOO include:

Green olive

Basil

Freshly Cut Grass

Tomato Plant

Artichoke

Green Apple

Almond

Fennel

Rosemary

                    Citrus Notes

These volatile compounds are fragile. Exposure to oxygen, light, and temperature fluctuations can degrade them, leading to flatter sensory profiles and eventual oxidative defects.

The Study: How EVOO Aroma Changes Over Time

Researchers Genovese A., Caporaso N., and colleagues investigated how EVOO aroma changes over time under controlled conditions designed to simulate household storage. Their work, published in Food Research International (2015), focused on: 

Overtime Changes in Virgin Olive Oil Volatile Components in Model Systems Mimicking Home Consumption: The Role of Biophenols

Experimental Design

To simulate real-world consumption:

• Twelve volatile aromatic compounds typical of EVOO were added to refined olive oil (a model system).
• Some samples were enriched with polyphenols.
  
• Samples were stored in darkness at 10°C for seven days.
• Volatile compounds were quantified using PME-GC/MS (Gas Chromatography–Mass Spectrometry).
  

It is important to note that this was a controlled model system, not freshly pressed EVOO, but it allowed precise measurement of volatile stability.

The Results: Polyphenols Preserve Aroma

The findings:

• Volatile aroma compounds decreased over time in all samples.
• Samples containing polyphenols experienced 17–44% less loss of volatile compounds compared to those without added phenolics.

What Does This Mean

In practical terms, oils richer in phenolic compounds are more resistant to oxidative deterioration.

Why Polyphenols Matter Beyond Health

Practical Implications for Consumers and Producers

For Consumers

• Choose freshly produced EVOO. 
• Store oil in a cool, dark place. 
• Keep bottles tightly sealed to minimise oxygen exposure. 
• Robust, early-harvest oils often (though not always) contain higher phenolic levels.

For Producers

• Optimise extraction practices to preserve phenolic content. 
• Minimise oxygen exposure during processing and packaging. 
• Use protective packaging such as dark glass or tins. 
• Emphasise phenolic content as both a health and quality parameter.

The Takeaway

This study demonstrates that polyphenols slow oxidative degradation and reduce the loss of volatile aroma compounds by up to 44% under controlled storage conditions.

They are not simply “health compounds.” 

They are stability compounds.

They help preserve the character, complexity, and personality of high-quality extra virgin olive oil.

When you open a bottle and inhale its vibrant green notes, those polyphenols are working quietly in the background - helping that aroma last longer.

References

• Based on research by Genovese A., Caporaso N., et al., Food Research International (2015).