Changes in volatile compounds of Ayvalik (Edremit) and Uslu olive oils depending on conditions and time of storage

Introduction. Volatile aromatic compounds present in olive oils extracted from Turkish olive cultivars including Edremit (Ayvalik) and Uslu were determined qualitatively. Materials and methods. The olives were harvested from Akhisar/Manisa region, which is one of most important Turkish olive-growing locations, at almost the same maturity stage by hand. Harvested olives were put in case and nylon sacks and were stored under the same conditions until they analyzed. Determination of the volatile aroma compounds were done with the aim of Headspace Solid-Phase Microextraction (HS-SPME) and Gas Chromatography-Mass Spectrometry (GC-MS). Results and discussion. 46 different volatile compounds were identified. The inappropriate storage conditions of olives had a negative impact on the aroma profiles of oils. The most abundant compounds were hexanal, alpha-farnesene, dimethylpalmitamine, and alpha-Farnesene, 2-hexanal, hexanal in olive oils extracted from Edremit (Ayvalik) and Uslu varieties, respectively.1-Hexanol was mostly increased compound in Edremit olive oils extracted from olives stored at nylon sacks during 14 days. The increase of concentration of 2-hexanal during holding periods could be explained by the activity of the fungal enzymes in Lipoxygenase pathway of olive fruits. While 5-Hepten-2-one 6-methyl and 1-Butanol 3-methyl were not detected in Edremit and Uslu olive oils at initial day, they formed during both sack and box holding due to the microbial activity in olives. Three principal components (PCs) were extracted representing 81.27% of the total variance of olive oil samples extracted from Uslu cultivar and 80.14 % of the total variance of olive oil samples extracted from Edremit cultivar. The first PCs, PC1, PC2 and PC3 represented 45.15 and 41.31%, 21.90 and 21.39%, 14.21 and 17.43%, for Uslu and Edremit varieties, respectively. Conclusions. It is recommended to store olives at 5 degrees C in air conditioning boxes for at least 30 days to reduce fungal development and to maintain the desired aroma.