Researchers at the University of Barcelona have discovered a new environmentally friendly method for extracting polyphenols from olive leaves.
In a study recently published in Food Chemistry, the scientists detailed a novel extraction method using Natural Deep Eutectic Solvents (NaDES).
The extraction method is crucial because it influences the costs and feasibility of processing olive leaves on a large scale outside the laboratory.
Additionally, it affects the composition of the extracted substances and their potential applications.
The researchers created the NaDES from natural components, combining a glycerol-like liquid substance with choline chloride, a solid salt used in animal feed.
“When you combine these two substances, a new solvent is formed,” said Sónia Sentellas, a researcher in the university’s department of chemical engineering and analytical chemistry and co-author of the study.
“It is a natural substance that does not have toxic impacts on human health,” she told Olive Oil Times.
The first step in producing the extract is to crush the leaves into a fine powder.
“Next, we mix a specific proportion of this powder with the solvent at 80 ºC for two hours and wait for the extract to be produced,” Sentellas said.
“The entire process is similar to making tea,” she added. “The tea leaves are steeped in hot water, which acts as a solvent. After a while, you get colored water with some tea components, and then you separate the leaves from the liquid.”
The researchers found that using NaDES improved extraction efficiency while adhering to environmentally friendly practices.
The study identified several polyphenols in the olive leaf extracts, including hydroxytyrosol, luteolin and oleuropein.
These compounds, also found in extra virgin olive oil, are known for their antioxidant properties and ability to protect cardiovascular and brain health.
While researchers are still exploring potential applications, this extraction process could benefit olive oil production, food packaging and cosmetics.
Additionally, large-scale production of olive leaf extracts could significantly impact the disposal of olive leaves.
Using natural, environmentally friendly, non-toxic solvents broadens the application profile of the obtained substances. More