HPLC analysis is one of the most important tools for documenting polyphenols in olive oil. It gives a measured value in mg/kg and makes it possible to connect a specific number to a specific batch.
For a premium oil, it is not enough to say "high polyphenol content". The value needs to be traceable to a sample, a method and a laboratory.
What is HPLC?
HPLC stands for High-Performance Liquid Chromatography. It is a laboratory method that separates, identifies and quantifies chemical compounds in a sample.
In olive oil, HPLC is used to analyse different phenolic compounds and their derivatives. These may include hydroxytyrosol, tyrosol, oleocanthal, oleuropein and other compounds that together form the oil's polyphenol profile.
The method is not a taste panel and not a health test. It is a chemical analysis.
How an HPLC analysis works
An oil sample is mixed with solvents to extract the polyphenols from the fat. The extract is then injected into an HPLC instrument, where the compounds are separated and measured.
In simplified terms, the analysis has three parts:
The column. The sample passes through a column packed with material that makes different compounds move through the system at different speeds.
The solvent flow. A controlled mixture of solvents drives the sample through the column with high precision.
The detector. When a compound passes the detector, a signal is recorded. The strength of the signal is used to calculate the amount of the compound.
The result is a chromatogram: a graph with peaks corresponding to different compounds. The peaks are compared with reference substances and used to calculate concentration.
What a mg/kg value actually represents
The result is often expressed in milligrams per kilogram of oil, mg/kg. It describes how much of the analysed phenolic compounds are present in the sample at the time of analysis.
A value such as 1,004 mg/kg is therefore not a feeling, an index or an estimate. It is a measured quantity in a specific sample, analysed with a specified method at a specified laboratory.
Vala Selection's reference batch 2025-VL-MIR-001 was analysed at the University of Split and measured at 1,004 mg/kg. That number describes the analysed batch, not a general promise that every future harvest will have exactly the same value.
Why HPLC values can differ between laboratories
Even when two laboratories use HPLC, results can differ. That does not automatically mean one analysis is wrong. It means the method needs to be understood.
Common differences include:
- Extraction method. Different solvents and procedures capture polyphenols with different efficiency.
- Column and solvent flow. Separation affects which compounds are clearly identified.
- Calibration. Quantification depends on reference substances and calibration.
- Which compounds are included. A broader or narrower selection affects the total.
This is why serious communication about polyphenol content should state batch, method and laboratory. A number without context is weaker than a number that can be traced.
What HPLC does not measure
HPLC measures chemical composition. It does not measure how the oil tastes, how long it will keep in your kitchen or what biological effect it has in the body.
That means the HPLC number should be used precisely. It can support that a batch contains a certain amount of analysed polyphenols. It should not be used as a standalone medical claim.
The EU-authorised health claim for olive oil polyphenols concerns protection of blood lipids from oxidative stress and is linked to a threshold per 20 g of olive oil. Read more on the page about polyphenols and oxidative stress.
Why HPLC matters for Vala Selection
Vala Selection works with small batches, clear origin and documented polyphenol content. HPLC analysis is part of that transparency.
It helps us:
- connect polyphenol content to a specific batch
- follow variation between harvest years
- communicate quality without exaggerated health claims
- show the difference between ordinary olive oil, premium oil and high-polyphenolic olive oil
This is also why we are careful with how numbers are presented. A high value is relevant only when it is traceable.
Further reading
On polyphenols as a group: polyphenols in olive oil.
On the EFSA claim and the threshold requirement: polyphenols and oxidative stress.
On individual compounds: oleocanthal and oleuropein.
Sources: HPLC analysis performed at the University of Split. IOC Trade Standard COI/T.15/NC No 3/Rev. 16. Batch 2025-VL-MIR-001.
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