Adding Water During Olive Oil Production Lowers Quality

Arbequina extra virgin olive oil produced without added water had higher levels of polyphenol and better oxidative stability than oils produced with added water. New research published in Food Chemistry has confirmed that adding water during the olive oil extraction process can profoundly affect extra virgin olive quality.

A team of Portuguese scientists evaluated what happens when water is added to the olive oil production process using Arbequina olives, one of the most widely grown olive tree cultivars in the Iberian peninsula.

They found significant differences in the water-added extra virgin olive oil compared to the same batch of olives processed with no water addition. The olives transformed without adding water had higher levels of polyphenols in the resulting oil and were far more resilient to oxidation.

The researchers analyzed the chemical and sensory profile of Arbequina olive oil extraction in several settings: from no water added during the production process to a maximum of 6.2% of water added for every kilogram of processed olives.

In all cases, with or without water, the resulting olive oils were classified as extra virgin olive oil, according to the International Olive Council standard.

“Despite the extra virgin olive oil classification, compared with the water incorporation… extraction without water addition resulted in [olive] oils that showed less primary oxidation (lower peroxide values and K232), greater total phenolic content (+12 to 22%) and higher oxidative stability (+22 to 31%),” the researchers wrote.

Additionally, olive oil produced without added water had a 5 to 13% higher secoiridoid content, mainly comprising oleacein, a powerful antioxidant.

As a result, olives transformed without any added water produced an oil with a more intense ripe fruity sensation.

The researchers concluded that olive oil production without adding water results in higher-quality Arbequina extra virgin olive oil with higher polyphenol counts. More