Effect of electrolytes, stirring and surfactants in the coacervation and microencapsulation processes in presence of gelatin

The objectives of the present study were to investigate the parameters affecting simple coacervation and the ability to encapsulate oleic acid using this technique. Coacervation has been achieved using different types of gelatin (bloom number, charge) and various electrolytes. The electrolytes used for the coacervation can be divided into three groups: (1) inert salts; (2) phase separation inducers, (a) precipitation inducing agents (PIA), and (b) coacervation inducing agents (CIA); (3) coacervation inhibiting agents. The encapsulation of oleic acid was evaluated with two types of gelatin and various emulsifiers (anionic, cationic and nonionic). For positively charged gelatin, it was found that the encapsulation is incomplete in presence of cationic emulsifiers. For negatively charged gelatin no general trend was observed. The stirring rate for each step of the preparation of the microcapsules was evaluated. It was found that high stirring is essential only in the cooling stage. The study was carried out in view of encapsulation of particular bacteria dispersed in the oil phase.