Slow release of pheromones to the atmosphere from gelatin-alginate beads.

Alginate-gelatin beads with dispersed droplets of a model pheromone, dodecyl acetate, were prepared as a vehicle for slow release of pheromones into the atmosphere over a prolonged period of time. The beads are prepared in two steps, the first being preparation of an oil-in-water emulsion composed of dodecyl acetate as the oil phase and gelatin as the emulsifier, which provides steric stabilization. After mixing with alginate solution, this emulsion is embedded within beads by simple electrostatic cross-linking. It was found that bead porosity at micrometric and nanometric scales plays an important role in controlling the release of dodecyl acetate.