Genipin-crosslinked gelatin films as controlled releasing carriers of lysozyme

The objective of this research was to fabricate novel gelatin films crosslinked by a naturally biochemical crosslinker (genipin) to achieve a controlled release of antimicrobial lysozyme. Lysozyme release kinetic studies were performed at acidic and/or neutral pH. Antimicrobial properties of the films were evaluated and an attempt was made to relate the antimicrobial activity of the films to release kinetics of lysozyme. The release kinetic profiles of lysozyme from gelatin films could be described as a two-step biphasic process, an initial burst effect followed by subsequent slower release, and close linear relationships between released lysozyme activities and incubating time were observed during burst release course. Genipin crosslinking retarded the release of lysozyme at pH 7.0, in a dose dependent manner, while lysozyme was rapidly released from the films at pH 3.8. Concomitantly, antimicrobial activity of the films decreased gradually as genipin concentration increased. The present data showed that gelatin films modified by genipin crosslinking efficiently retarded the release of lysozyme, being a promising way to extend antimicrobial effects during food storage and to enhance food safety. (C) 2012 Elsevier Ltd. All rights reserved.