Antioxidant Activity, Physico-Chemical and Fatty Acid Composition of Oleaster (Elaeagnus angustifolia L.) Varieties Naturally Grown in Western Mediterranean Region of Turkey

Elaeagnus angustifolia L. belongs to the family of Elaeagnaceae, and its fruits are consumed as an appetizer. Mesocarp tissue of Elaeagnus fruits contains mainly carbohydrates while endocarp part (kernel) is rich in lipids. In this study, fatty acid profiles and nitrogen contents of the endocarp tissues of four different Elaeagnus angustifolia varieties naturally grown in the Western Mediterranean Region of Turkey were determined as well as the total phenolic and flavonoid contents and antioxidant activity of their mesocarp and exocarp tissues. The crude fat content of endocarp tissues of Elaeagnus fruits ranged from 24.45 to 30.13%, and the highest nitrogen content (0.205%) was in the Native variety. The dominant fatty acid in endocarp tissue lipids was linoleic acid (ca. 48%), and the content of mono- and polyunsaturated fatty acids in this tissue was about 90%. Varietal differences were found in the total phenolic and flavonoid contents and antioxidant activities of mesocarp and exocarp tissues. The mesocarp tissues of Sugar variety had the highest total phenolic content (161.9 mg GAE 100/g dry matter (dm)) and antioxidant activity (118.3 µmol Trolox® equivalent (TE) g dm) while the highest total flavonoid content (216.5 mg catechin equivalent (CE) 100 g dm) was in the exocarp tissue of Native variety. Results indicated that endocarp tissue lipids can be a good source of polyunsaturated fatty acids for human consumption in food, feed and cosmetics industries.