Impact of olive leaves powder addition on extra virgin olive oil: Sensory, quality, nutritional and volatile compounds implications

Olive leaves currently represent a waste from olive oil industry that can be reused as source of polyphenols and other compounds. The objective of this study was to test whether incorporation of olive leaf powder directly in olive oils can enhance and modify its chemical-sensory quality. Thus, leaves from cultivar "Koroneiki" were washed, sanitized, dried (37-40 degrees C for 48 h) and milled until obtaining a powder that was added to "Arbequina" and "Koroneiki" extra virgin olive oils, at 1% and 3%. The oils were stored in dark conditions at room temperature and samples were checked after 0, 3, 6 and 12 months. The quality parameters, sensory properties, and nutrition quality (total phenolics, antioxidant, oleuropein and alpha-tocopherol) were evaluated. The olive leaves affected quality and chemical composition, mainly increasing resistance to oxidation, which was not verified in samples without leaves addition. The incorporation of leaves powder significantly increased the contents of C6-C5 alcohols/aldehydes, intensity of the green fruity and bitter, also artichoke, herbs, tomato leaf, olive leaves and banana peels sensations.