Simultaneous Recovery of High Quality Black Sesame Oil and Defatted Meal by a New Aqueous Method: Optimization and Comparison with Other Methods.

A method able to simultaneously obtain oil and defatted meal (rich in proteins) with high quality is preferable to others for processing black sesame seeds, which should also be green, healthy, highly efficient and sustainable. Methods including solvent extraction and hot-pressing currently available for the commercial production of oils are not able to meet all criteria just mentioned above. Therefore, development of new aqueous method of extracting black sesame oil has been promoted. In our study, we developed a new aqueous method using 1.95:10 aqueous salt solution-to-ground black sesame seed ratio which simultaneously recovered 96.54% black sesame oils and defatted meal with only 3.89% residual oils and 50.1% proteins (on dry weight basis). The oil produced had low acid value at 0.43 mgKOH/kg and peroxide value 3.37 mmol/kg and good other quality indexes. We found that proper amount of water added was essential for efficiently recover black sesame oils while other factors including temperature and time of baking raw materials to deactivate lipase activity, pore size of the sieve for ground black sesame seeds to pass through, addition of salt as well as temperature and time of agitating significantly affected the recovery efficiency. As compared with other methods, the new aqueous method had higher oil recovery rate or quality and was more environmentally friendly. No waste water was discharged during separation of oils. The experimental data can be applied to guide the design and manufacture of production line of black sesame oilseeds on a pilot or commercial scale.