Use of a tubular heat exchanger to achieve complex coacervation in a semi-continuous process: Effects of capsules curing temperature and shear rate

Abstract

The main objective of this study was to convert the cure of the capsules produced by complex coacervation in a continuous process. To achieve this, a continuous tubular heat exchanger was used. The complex coacervation step was induced by atomization and compared with the traditional batch stirring method. Immediately after the coacervation step, the influence of curing step was evaluated by varying the tubular heat exchanger curing flow rate (2.4, 5.3 and 8.3 mL/s) and the curing temperature (8, 10 and 11.5 °C). One important result reported in this study is the reduction in overall time to cure the capsules, that varied from 2.7 to 9.4 min. The capsules size varied from 22 to 36 μm, the encapsulation yield ranged from 66 to 93% and the maximum oil released during simulated gastric conditions was less than 14%. This indicates that this new configuration to carry out complex coacervation in a semi-continuous process is effective in producing proper capsules and it opens important possibilities to scale up the process, making it cheaper, faster and more efficient.