The Use of Olive Leaves in Buza Olive Cultivar Oil Production: Exploring the Impact on Oil Yield and Chemical Composition

The effect of the addition of different amounts of olive leaf (1, 2.5, and 5%, m/m) during Buza olive cv. oil production on the quantitative production parameters, composition, and sensory characteristics of the obtained oils were investigated in this study. The addition of leaf during oil extraction increased oil yield and extractability index by 97% compared to the control oil. The addition of leaf during extraction increased the concentration of pigments in oils, and the oil positive sensory attributes intensities, such as fruitiness and green grass/leaf notes. The influence on oil phenolic composition was dependent on the amount of leaf added. When 1% leaf was added, most of the phenolic compounds were preserved, while the addition of leaf at 5% decreased the concentration of the majority of phenols, especially secoiridoids by 45% compared to the control oil. The addition of leaf slightly increased the concentration of fatty acid ethyl esters and waxes in the oils. The obtained results indicate that particular importance should be given to the amount of olive leaf present in olive paste during oil extraction, since it apparently can increase the extractability of oil, but can also have negative effects on phenolic composition when added in excess.