How different amounts of leaves added during the extraction process affect the biochemical composition of Chemlali olive oil cultivar?

Olive leaves are rich in antioxidant compounds. During harvest, they reached about 10% of the total weight which can affect the olive oil quality. So, this work aimed to study the effect of adding different amounts of leaves (1, 2, 5, 10 and 20%) during the olive oil extraction of cv. Chemlali. Changes in physico-chemical indices, oil stability, fatty acid composition, antioxidant contents and volatile composition were evaluated. The obtained olive oils with the addition of less than 10% leaves were classified as Extra Virgin Olive Oil (EVOO). Polyphenols and bitterness index were the highest for treatments with addition of less than 10% leaves. Twenty-nine volatile compounds were identified. Total aldehydes and C6 compounds, responsible of the positive attributes, were the most abundant and were strongly affected by the addition of leaves. Olive oils with 2 and 5% added leaves were rich with aldehydes responsible of green and fruity flavor and in polyphenols.