Investigation of the effect of harvest time and ripening index of olive fruit on the chemical-sensory attributes and yield of olive oil

This research was carried out to determine the influence of different harvest time and degree of olive ripeness on olive oil yield, chemical and sensory properties of olive oil. For this purpose, extra virgin olive oils extracted from 4 local cultivars were investigated in the study. Olive fruit samples were picked at three different stages of ripening in two consecutive years. Maturity index, moisture content and oil content were determined on these samples. Olive oil extracted from the same samples were analyzed in terms of free fatty acid, peroxide value, UV absorption characteristics, total phenols, oxidative stability, fatty acid composition and sensory analysis. According to the results obtained from this study; Kilis Yaglık was found superior to other varieties in terms of oil yield, bitterness, pungency, total phenol content and the induction period. A spicy aroma was recorded in the sensory analysis of the oil. The ideal harvest time for Kilis Yaglık was found in the medium harvest period. Induction period of Gemlik oil was found to be higher than Ayvalık and Memecik oil. Panelists determined a mint aroma in the oil of Gemlik variety. The ideal harvest time for this variety was found to be late harvest period. Memecik had the most intense fruity character and its bitterness and pungency were found to be high intense after Kilis Yaglık variety. In the sensorial analysis, flower and bitter almond aroma were sensed by the panel. Medium harvest or late harvest was the ideal period for Memecik variety. Ayvalık variety was found to be behind the other varieties in terms of phenol induction period, oleic acid content, MUFA/PUFA ratio and bitterness-pungency attributes. It had a high fruity character. The ideal harvest time was medium period when oil yield was taken into account and medium or late harvest time when the other attributes were considered. Tea and green almond aromas were determined in the oil by the panelists.