Improving oxidative stability of sunflower oil by infusion of antioxidant-rich herbs

Abstract

Vegetable oils are oils extracted from nature fruits and seeds. They are used everywhere in the daily life, mostly in foods, in cosmetics, in pharmaceutical products, as biodiesel fuel and many other applications. When exposed to light, heat, and air, they become unhealthy by undergoing oxidation. In this project, the focus was done on sunflower oil. The target was looking for a way to improve the quality of this oil. Nine herbs were selected (basil, rosemary, cinnamon, thyme, oregano, red pepper, sage, green tea and bay leaf), that contain an amount of antioxidants which may slower or even inhibit the oxidation of oil. These herbs were left to infuse in the oil for eight days. The polyphenol content and oxidative stability were then assessed. Among these oils, sage- and rosemary-infused oils were found to contain the highest amount of polyphenolic compounds. Sage antioxidants were found to be able to preserve their effect during frying and contribute to the highest oxidative stability of oil.