Synthesis and characterization of novel antimicrobial emulsifiers from epsilon-polylysine

epsilon-Polylysine (EPL) has been used in the food industry as an antimicrobial additive and also a dietary agent. To generate amphiphilic molecules from EPL, hydrophobically modified epsilon-polylysine graft copolymers, which were denoted as OSA-g-EPLs, were synthesized by reacting EPL with octenyl succinic anhydride (OSA). The success of synthesis was confirmed by (1)H NMR and FT-IR spectroscopy. It was found that OSA-g-EPLs had glass transition temperatures lower than EPL. Furthermore, they were able to form polymer micelles in water and to lower the surface tension of water, confirming their amphiphilic properties. The antimicrobial activities of OSA-g-EPLs were also examined, and the minimum inhibitory concentrations of OSA-g-EPLs against Escherichia coli O157:H7 remained the same as that of EPL. Therefore, OSA-g-EPLs have the potential of becoming bifunctional molecules, which can be used either as surfactants or emulsifiers in the encapsulation of nutraceuticals or drugs or as antimicrobial agents.