Oxidative Stability of Virgin Olive Oil Supplemented withZataria multifloraBoiss. andRosmarinus officinalisL. Essential Oils During Accelerated Storage

The aim of this study was to investigate the effects of Zataria multiflora Boiss. and Rosmarinus officinalis L. essential oils (EOs) on oxidative stability of virgin olive oil (VOO). Antioxidant activity indices (peroxide, p-anisidine, K232 and K268 values) of EOs were compared with those of BHT and β-carotene. As a result, the lowest peroxide value, p-anisidine value, K232 and K268 values were determined in samples containing BHT and Z. multiflora EO. The R. officinalis EO significantly reduced VOO oxidation with an induction period extension of 17.73%. Comparatively, BHT and Z. multiflora EO were more effective in reducing VOO oxidation, with an induction period extension of 63.72 and 48.90%, respectively. The β-carotene exhibited pro-oxidative effects toward primary and secondary oxidation products and reduced the induction period of VOO by 3.29%. It can be concluded that Z. multiflora and R. officinalis EOs can be used to extend the shelf life of VOO. Practical Applications VOO is one of the few oils being consumed without any refining treatment. One of its most important quality problems is oxidative rancidity. Synthetic antioxidants such as BHA and BHT are used extensively to prevent oxidation. However, synthetic antioxidants are not permitted to be incorporated into olive oil. The current study investigated the effect of Zataria multiflora and Rosmarinus officinalis EOs as sources of natural antioxidants on the oxidation of VOO. The present results indicate that Z. multiflora and R. officinalis EOs can serve as natural antioxidants for improving the oxidative stability of VOO.