Co-encapsulation of Lactobacillus acidophilus (La-5) and omega-3 rich oil through complex coacervation

Co-encapsulation of Lactobacillus acidophilus and Tuna oil rich in omega-3 fatty acids using Soy protein isolate (SPI) and Arabic gum (GA) as wall materials was studied through the complex coacervation method. The microcapsules were dried separately by freeze and spray drying. The optimal conditions for the coacervation between soybean protein isolate and gum Arabic as functions of pH, SPI/GA ratio and total concentration of biopolymers were investigated using zeta potential, turbidity, and coacervation yield assays. The highest coacervate yield was achieved in the total concentration of biopolymers 2% (w/v), SPI/GA ratio 60:40 and pH=4, and the highest coacervation yield was 79.22±1.75%. Lactobacillus acidophilus (La-5) viability was significantly (p˂0.05) higher in freeze-dried microcapsules in comparison with spray-dried microcapsules. Omega-3 fatty oil improved significantly (p˂0.05) the viability of probiotic bacteria during 60 days storage in ambient temperature and gastrointestinal conditions. The size of L. acidophilius containing microcapsules and co-microcapsules (SPI-P-O-GA) were 1.19±0.19 and 4.42±0.14 µm, respectively.