Application of extracts and essential oils with antioxidative properties to stabilize edible oils is a usual approach. However, this needs extraction of essential oils and extracts which is time consuming and costly. A new method is using herbs with oilseeds during the oil extraction by press. In this study, rosemary leaf at 0 (control sample), 2.5, 5, 7.5 and 10% (w/w) was added to black cumin seeds (BS) and oil then extracted by screw press. Extracted oil qualitative properties were determined in production day and every 30 days during 90 days of storage. Obtained results showed that level of essential oil increased (from 0.1 to 0.77%) by increasing the level of RL. Peroxide value of the extracted oils was decreased from 20 to 8.8 (meqO2/Kg oil) by increasing the RL with higher oxidative stability during storage. Acidity was increased in the oil samples extracted from the BS with RL higher than 5%. Chlorophyll and carotenoids contents were increased from 52 to 204 (mg/kg oil) and 5.2 to 13.7 mg/kg oil, respectively, but their content decreased due to decomposition about by half during storage.  In conclusion, obtained results showed that new method of pressing BS incorporated with RL an herb with antioxidative properties is possible and could give a new product and an oil with higher oxidative stability.

Keywords: Oxidation, oxidative stability, quality, medicinal herbs

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