Effect of Lavender and Thyme incorporation in sunflower seed oil on its resistance to frying temperatures

Extending the frying life of oil is of commercial and economic importance. Therefore, improving the thermal stability of cooking oils could provide considerable savings to the food processors. In this study, three different frying temperatures i.e., 150, 180, 200 degrees C, were applied to refined sunflower seed oil before and after addition of two kinds of natural herbs. A number of official methods were used to evaluate chemical and physical changes in all samples during heating. Quality parameters of sunflower seed oil were improved by treatment with either Lavender or Thyme. In fact, the statistical analysis of results proved the existence of a significant difference between untreated and treated oil samples. However, no difference was found between sunflower oil with lavender and sunflower oil with thyme, whenever the same temperatures were applied. Thyme and Lavender exhibited a high ability in reducing free fatty acids content (FFA), peroxide value (PV), and Viscosity. The incorporation of Lavender and/or Thyme in sunflower seed oil helped to improve its thermal stability and, consequently, to extend its frying life. (c) 2006 Elsevier Ltd. All rights reserved.