Storage Stability of Sunflower Oil with Added Natural Antioxidant Concentrate from Sesame Seed Oil

Abstract

Demand for use of natural additives such as nutraceuticals, antioxidants, coloring and flavoring matter is continuously increasing world over. It is due to nutritional awareness among the masses and belief that most of the natural products are safe for human consumption. Interest has been shown recently on the use of natural antioxidants from oil seeds. Hence, oils obtained from sesame (Sesamum indicum) had been utilized for this purpose. Oils were thermally treated (T) to enhance the sesamol content from 4,900 to 9,500 ppm. A portion of resultant oil had been extracted with ethanol in a controlled conditions to yield a concentrate (ESSO-T) with sesamol content of 28,500 ppm. Whereas another portion after silica gel column separation yielded a concentrate (SSO-TFII) with sesamol content of 27,100 ppm. Refined sunflower oil without antioxidant was mixed with ESSO-T and SSO-TFII separately at the level of 2,000, 1,000, 500 and 200 ppm and its storage stability assessed was at ambient (22-28°C) and elevated (37 °C) temperatures. Peroxide value (PV) and Free Fatty Acid content (FFA) of samples were estimated at intervals of 2 weeks for a total storage period of 12 weeks. Results indicated that ESSO-T at the level of 500 ppm had maximum protective effect on refined sunflower oil, where PV and FFA were found ranging between 2.1 to 5.9 and 0.10 to 0.15%; and 4.1 to 9.8 and 0.11 to 0.21% for samples stored at ambient and elevated conditions respectively. The storage stability of this sample was very close to the storage stability of sunflower oil containing TBHQ at 200 ppm. Comparatively in sunflower oil without antioxidant PV and FFA had gone up from 2.0 to 45.4 and 0.11 to 1.3% at ambient and 2.0 to 56.4 and 0.11 to 2.8% at elevated temperatures.