Lysozyme/tripolyphosphate complex coacervates: Properties, curcumin encapsulation and antibacterial activity

Complex coacervates based on the combination of two oppositely charged biopolymers have been proposed as encapsulating and protective platforms for bioactive agents in food science. Lysozyme, an enzymatic protein used as a natural food preservative, was combined with other macromolecules (proteins and polysaccharides) to generate coacervate formulations. In this study, the design of coacervate-like structures based on lysozyme was extended through their combination with multivalent tripolyphosphate anion, a non-macromolecular food additive. It was observed that direct mixing led to the formation of complex coacervates under certain ranges of pH, ionic strength, and component concentrations. Coacervates presented a suitable capacity to encapsulate poorly water-soluble curcumin. More interestingly, coacervates improved the chemical stability (under long-term storage and light irradiation) and antibacterial activity of curcumin. Therefore, these single macromolecule coacervates could be exploited as an active carrier platform for encapsulation in food applications.