Optimization of microencapsulation of seed oil by response surface methodology

Abstract

The response surface methodology (RSM) was employed to optimize the microencapsulation condition of sunflower oil (SO) as a typical seed oil. The microencapsulation efficiency (MEE) of microencapsulated sunflower oil (MESO) was investigated with respect to four variables including SO concentration ( X 1), proportion of milk protein isolates (MPI) to coating wall ( X 2), soy lecithin concentration ( X 3), and homogenizing pressure ( X 4). As a result, a polynomial regression model equation was fitted as follows: MEE ( % ) = 4.137772 + 3.524183 X 1 + 3.475205 X 2 + 2.914167 X 3 - 0.074532 X 1 2 - 0.067482 X 2 2 . Effect of homogenizing pressure was negligible. The optimal conditions for microencapsulation of SO were 23.6% SO, 19.0% MPI, 2.5% soy lecithin, and 54.8% dextrin, respectively. MESO under the optimized conditions gave rise to the highest MEE, approaching 96.6% of MEE. Compared to MESO showing a low MEE (70.2%), the peroxide value (POV) of the total oil from the MESO under the optimized conditions was significantly lowed even under the accelerated storage conditions at 60 ± 1 °C after 30 days, which indicates a promising feature of RSM-mediated microencapsulation process of seed oil.