Effects of Different Manufacturing Processes on Thermal and Photo-oxidative Stability of Sesame Oil.

The roasting process of sesame oil is expected to alter its internal composition and stability under oxidation condition. Presumably, the effect of roasting may differ with oxidation conditions (i.e., thermal and photo-oxidation), but such studies have not been undertaken. To further evaluate this notion, several type of sesame oils (raw and refined as unroasted oil, and roasted oil) and rapeseed oils as comparison were subjected to thermal oxidation (120℃) and photo-oxidation (50,000 lx) for 5 and 10 hours. The result revealed that the roasting sesame oil exhibited good stability under thermal oxidation, possibly due to the change on antioxidant agents such as sesamol and Maillard products during the roasting process. In contrast, the refined sesame oil (unroasted) demonstrated high stability under photo-oxidation, indicating that the refining process has a more significant impact on the oxidative stability in sesame oil compared to the alterations in its components caused by the roasting process. Taken together, this study is the first to show that the roasting and refining processes of sesame oil alter its internal composition and show different variations in sesame oils' oxidative stability under thermal and photo-oxidation, which holds significance considering its global consumption.