Optimization of Roasting Process of Sesame Seed to Produce High Quality Sesame Oil

Sesame oil because of having lignans such as sesamin and sesamolin has greater resistance against oxidative degradation as compared to other edible oils. Roasting process can make a tremendous positive impact on the oxidative resistance of the oil. The aim of this work was to evaluate the roasting conditions of sesame in terms of temperature and time using response surface methodology regarding the highest rate of oxidative resistance and best color of roasted sesame oil. In order to evaluate the roasting conditions, the two factors of temperature (200, 215 and 230 °C) and time (15, 25 and 35 min) were used in 3 levels. The total number of tests for each sample was 12 and oxidative resistance and color (XE and L index) were considered as responses. After data analysis by the software, statistical analysis of the models related to the stability and color (XE and L index) were evaluated. The results indicated that the temperature was more effective than the time in oil oxidative resistance changes and by increasing the temperature and time, the oxidative resistance and XE index increased while L index decreased. The optimal condition of roasting for brown sesame seeds was at the temperature of 216.86°C and time of 19.32 minutes while for the white type, the temperature of 220.47°C and the time of 15 minutes were considered as the optimum condition.