This study was aimed to bleach olive and sunflower oils by using conventional and ultrasonic methods. The qualitative and quantities characteristics of the bleached oils were compared. The used ultrasonic bath (150 W, 20 kHz) was set at two levels of temperatures (45 and 60C). Series of tests including of chlorophyll and carotenoid, color, peroxide value, acidity measurements and free fatty acid (FFA) determination were carried out. By application of conventional bleaching a considerable reduction in chlorophyll and carotenoid contents of olive and sunflower oils were observed, while better removal of the pigments was obtained after ultrasonic treatment for 20 and 30 min at 45 and 60C without any significant negative effect on the fatty acid composition. It might be concluded that the ultrasonic bleaching process can be considered as an alternative method for conventional bleaching method since it could decline the time and temperature of bleaching process. PRACTICAL APPLICATIONSTechnical information related to the possible effects of application of ultrasonic bleaching on some of quality parameters of olive and sunflower oils was provided by current study. Ultrasonic waves could improve the bleaching process without any destructive effect on the fatty acids profiles. The suggested method can be used in oil refining industry as alternative to current conventional producer due to reduction of the time and temperature of bleaching process.

Degumming is an essential process in refining of the vegetable oils. In current study application of the ultrasonic waves in combination of the phosphoric acid to reduce the temperature and duration of degumming process was investigated, therefore obtained results were compared with the conventional methods. Hence, crude soybean and sunflower seed oils were degummed in the presence of acid in the ultrasonic bath (150 W, 20 kHz). The oils were also degummed by the conventional method at 60C for 30 min. Some quality factors such as phosphorus content, peroxide value, acidity, resistance to the oxidation and also the fatty acid profile were determined. According to findings the required temperature and process time has been decreased when ultrasonic waves were used. In addition the introduced method did not have significant effect on the fatty acid composition of oils and might be used as an alternative method for degumming of the vegetable oils. Practical Applications The application of ultrasonic waves is known as a safe and moderate method in different industries. As it has been shown in this study ultrasonic waves can improve the degumming process. The results of this study can be used in oil refining industry and ultrasonic degumming as a good alternative method to the other methods of degumming such as conventional degumming which needs a long time and high temperature.