Influence of the olive ripening and nonthermal plasma process on aroma-active, phenolic compounds and other quality parameters of virgin olive oil

In this research, extra-virgin olive oils obtained from Nizip Yaglik olive variety, one of the important olive varieties of Turkey, during the different olive ripening stages (about 2.5, 3.5 and 4.5 maturity index values), were used to investigate aroma profıle and phenolic compounds by instrumental, biotechnological, sensory and chemometric methods. Aroma profile in the olive oils obtained at diverse fruit ripening periods and their aroma-active compounds that characterized these oils were first time determined by GC-MS-O techniques. The extraction of the aroma compounds were made by solvent-assisted flavor evaporation (SAFE) method which was applied in olive oil for the first time. Additionally, phenolic compounds by using LC-MS-MS technique and other quality parameters of olive oils were investigated in details. The olive oil obtained from the optimal maturity stage (3.5 maturity index) according to the sensory analysis was treated by the cold-plasma technology for the first time to investigate the quality changes such as aroma profile, phenolic compounds, antioxidant capacity and lipoxygenase enzyme activity. In the results of analysis, the type and number of aroma and aroma-active compounds of olive oils exhibited significant differences with respect to the maturation indexes of olives. Moreover, the type and number of aroma, phenolic compounds didn't show any differences in oils after non-thermal plasma treatment, however, their concentrations mildly changed. Key Words: Olive oil, Maturation index, Cold plasma treatment, Phenolic compounds, Aroma profile, Aroma-active compounds, Olfactometry