Effect of Thymus haussknechtii and Origanum acutidens essential oils on the stability of cow milk butter

The aim of this study was to investigate the effects of different essential oils (from Thymus haussknechtii Velen and Origanum acutidens Hand.-Mazz. Letswaart; endemic species in Turkey) on butter stability. These essential oils were added to butter at two concentrations (0.1 and 0.2 wt-%). The antioxidant activities of the essential oils were compared with control samples (without antioxidant) and containing butylated hydroxytoluene (BHT). All samples were stored at 4 +/- 1 degrees C for 90 days and their peroxide values (PV), thiobarbituric acid (TBA) values, % titratable acidity and some microbiological properties were analyzed. As a result, the lowest PV and TBA values were determined in the samples containing BHT and 0.2% essential oils; however, TBA and PV were at the highest levels in the control samples during storage. The amount of 0.2 A of essential oils exhibited strong antioxidant activity, which was almost equal to that of BHT. T haussknechtii essential oil showed a stronger antioxidant effect as compared to O. acutidens. None of the essential oils showed remarkable antifungal activity. However, the antimicrobial activity of O. acutidens on coliform bacteria was found to be higher than that of T. haussknechtii. Sensory analysis of the butter showed that the samples containing 0.2% essential oils had lower flavor scores than those with 0.1% essential oils. The present results indicate that these essential oils can be considered as an alternative source of natural antioxidants in the manufacture of butter.