M.A. Thesis:

effect of temperature and extraction time on some quality characteristics of sesame oil extracted by ultrasonic process

Sesame oil because of the polyunsaturated fatty acids and also due to its constituents,reduce blood pressure and cholesterol in humans. In this study, sesame, after the initial test, grinding, and was combined with hexane a ratio of 1 to 5 and In temperatures of 35, 45, 55 ° C in the ultrasound bathroom, were heated at the time 30,60 and 90 minutes and At the same time exposed to ultrasonic waves at a fixed frequency of 50 Hertz (Hz) and 100% power (350 watts) were used. Then the oil was extracted from the seeds, and the properties of extraction efficiency, saponification index, iodine index, peroxide value, acidity, color Lavyband method, refractive index and oxidative stability was measured. According to the results of this research, produced oils by increasing the duration and increase the temperature of ultrasound, yield of oil extraction increased. The fatty acid profile, saponification and iodine value, refractive index and colorimetric parameters were not affected by temperature and time of ultrasound. Acidity, increased with increasing temperature and time, peroxide at temperatures of 35 and 45 with increased time, increased, and at 55 ° C decreased with increasing time. Thermal stability also had the highest rate at 35 to 30 minutes. According to the results 60 minutes at 35 ° C was selected the best treatment of ultrasound for the extraction of oil from sesame.

Keywords: oil, sesame, thermal stability, gas chromatography