Abstract: The microencapsulation of functional lipids was optimized using one-factor-at-a-time and orthogonal array design methods. Sodium alginate was used as the wall material, and calcium chloride solution as the curing agent. The voltage was 2 000 V and the curing process lasted for 30 min at a stirring rate of 50%. The response variable was microencapsulation efficiency. A sodium alginate concentration of 1.6%, a frequency of 620 Hz, a CaCl2 concentration of 1.5% and a feeding rate of 4.0 mL/min were found to be the optimal conditions to obtain a higher microencapsulation efficiency of (88.32 ± 0.28)%. The microcapsules under scanning electron microscope (SEM) showed a uniform spherical shape with smooth surface. The microcapsules were yellowish in color and had a mononuclear structure under stereomicroscope. Fourier transform infrared spectroscopy showed that the microcapsules contained the characteristic peaks of lipids and the chemical structure of the core did not change. Thermogravimetric analysis showed that the microcapsules had good thermal stability at below 250 ℃. Moreover, the microcapsules significantly increased the oxidative stability of the core material under the accelerated storage conditions.

Key words: sodium alginate, microcapsules, microencapsulation efficiency, functional lipids