Effect of Roasting and Vacuum Microwave Treatments on Physicochemical and Antioxidant Properties of Oil Extracted from Black Sesame Seeds

Unroasted, roasted (at roasting temperatures of 100, 150 and 200 degrees C and roasting times of 10, 20 and 30 min) and vacuum microwaved (at microwave watt powers of 800, 1440, 2400 and 3600 watts/kg black sesame seeds, for heating times of 10, 20 and 30 min) black sesame seeds were processed to extract oil using a single screw press at a constant pressing temperature of 50 degrees C. The results revealed that different heat pre-treatments significantly affected yield and physiochemical and antioxidant properties of extracted oils. The extracted oil samples exhibited significantly different levels of total phenolic compounds, sesamin, sesamolin, and DPPH center dot and ABTS(center dot+) scavenging activity. Additionally, it was found that these values of roasted and vacuum microwaved black sesame seed oils were significantly higher than those of unroasted oil. Sesamin, sesamolin, total content of phenolic compounds, and DPPH center dot and ABTS(center dot+) scavenging activity of extracted black sesame oils increased when the roasting temperature and watt power increased. Black sesame oil obtained from unroasted, roasted and vacuum microwaved dried black sesame seeds contained linoleic and oleic acids as major fatty acids. Black sesame oil extracted from roasting and vacuum microwave treatments for 10 min at higher roasting temperature and microwave watt power had higher total phenolic content leading to a reduction of peroxide value and elevated stability of soybean oil when it was added during storage time at temperature of 65 degrees C.