Effect of Maturation Index on Total Phenolic Content and Bitterness Index of Natural Olive Oils
Aytac Saygin Gumuskesen, Sibel Erdogan Capar
Ege University Food Engineering Department 
Izmir, Turkey

Virgin olive oil has a high resistance to oxidative deterioration due to both a triglyceride composition low in polyunsaturated fatty acids and a group of phenolic antioxidants composed mainly of polyphenols and tocopherols. Polyphenols are of greater importance to virgin olive oil stability as compared with other refined oils. Refined seed oils undergo refining processes through which elevated temperatures lead in thermal and hydrolytic breakdown of tocopherols. Therefore natural olives contain high amounts of phenolic compounds and tocopherols which give them an added nutritive value and stability. Phenolic content of olive oils strongly depend on agronomic and technological factors during maturation, harvest, storage and olive oil production.  In this study, the effect of ripening index of olive fruits as an agronomic parameter on the total polyphenol content of virgin olive oil is investigated. Maturation index is found to be effective on total phenolic content of natural olive oils. Moreover bitterness index also correlates well with total phenolic content of olive oils.