Olives contain a range of phenolic compounds such as tyrosol, hydroxytyrosol or oleuropein which are responsible for many of the health benefits associated with virgin olive oil. In addition to these properties, phenolics protect the oil against oxidation. Phenolics are characteristic of virgin oil as they are lost during refining.
Phenolic supplementation of native virgin oil cannot be achieved by simply mixing the oil with high concentrations of the phenols due to the hydrophilic nature of the olive phenolics. These compounds need to be emulsified in order to be dispersed in the oil. Suárez and co-workers, University of Lleida, Spain, studied two emulsifiers for this purpose, lecithin and monoacylglycerols.
Lecithin was the more effective emulsifier of the two and the enriched oil displayed high oxidative stability, high phenol content, improved antioxidant capacity, and acceptable bitterness index — this is an additional advantage of using the emulsifier which “masks” the bitter taste of the phenols.
- Stability of a phenol-enriched olive oil during storage
M. Suárez, M.-P. Romero, T. Ramo, M.-J. Motilva,
Eur. J. Lipid Sci. Technol. 2011, 113, 894-903.