Changes occurring in chemical composition and oxidative stability of virgin olive oil during storage

Abstract

In present study, “Saurani” Turkish olive monocultivar extra virgin olive oil (EVOO) was extracted by using Mobile Olive Oil Processing Unit (MOOPU)” (TEM Oliomio 500-2GV, Italy). Free fatty acid content, peroxide value, moisture content and UV absorbance value, minor and major components and quality characteristics changes were surveyed during a year storage. “Saurani” olive oil samples weren’t categorized as EVOO according to the trade standards of International Olive Council (IOC) based on peroxide value, UV absorbance values after five and two months of storing, respectively. Free fatty acid content of VOO samples increased during 12 months’ storage, but it was under the IOC limitation for extra virgin olive oil (< 0.8%). According to the results, color values of VOO changed from green to yellow while UV absorbance values altered during storage. Total phenol content decreased from 342.95 to 252.42 ppm in EVOO samples during a year storage time. Luteolin was the most abundant phenolic compound and its decrement was 10%. Tyrosol content of VOO samples increased from 2.80 to 8.81 ppm. Except tyrosol, other phenolic compounds’ concentration decreased after a year storage time. α-tocopherol contents of VOO sample were 324.60 ppm. After 12 months of storage, about 20.48% of α-tocopherol content was destroyed. Amounts of phenolic and tocopherol isomers decreased during storage as expected. Results of this study showed that chemical composition and oxidative stability of VOO samples changed significantly.

Keywords

• olive oil
• saurani
• phenolic compounds
• tocopherol
• storage