Swelling behavior and the release of protein from chitosan¯pectin composite particles

Pectin solution gelled with chitosan and Ca2+ ion produced composite particles with a double-layer structure. Response surface analysis revealed that the particle swelling at pH 1.4 was influenced significantly by chitosan and Ca2+ concentrations. Chitosan and Ca2+ concentrations also significantly influenced the swelling in pH 7.4 buffer at 4 h, whereas chitosan and pectin concentrations significantly influenced the swelling in pH 7.4 at 12 h. Results from swelling experiment and statistical analysis suggested that complex formation between chitosan and Ca2+, or between chitosan and pectin might have occurred. Negligible protein was released from the chitosan¯pectin particles in pH 1.4 buffer. The chitosan¯pectin particles could sustain the release of most loaded protein until after 24 h in pH 7.4 buffer. Pectin degrading enzyme increased the protein release from 39 to 63% within 12 h in pH 7.4 buffer. These characteristics of the chitosan¯pectin particles would be useful for colon-specific delivery of bioactive macromolecules.