Perspectives for chitosan based antimicrobial films in food applications

Recently, increasing attention has been paid to develop and test films with antimicrobial properties in order to improve food safety and shelf life. Active biomolecules such as chitosan and its derivatives have a significant role in food application area in view of recent outbreaks of contaminations associated with food products as well as growing concerns regarding the negative environmental impact of packaging materials currently in use. Chitosan has a great potential for a wide range of applications due to its biodegradability, biocompatibility, antimicrobial activity, non-toxicity and versatile chemical and physical properties. Thus, chitosan based films have proven to be very effective in food preservation. The presence of amino group in C2 position of chitosan provides major functionality towards biotechnological needs. particularly, in food applications. Chitosan based polymeric materials can be formed into fibers, films, gets, sponges, beads or even nanoparticles. Chitosan films have shown potential to be used as a packaging material for the quality preservation of a variety of food. Besides, chitosan has widely been used in antimicrobial films to provide edible protective coating, in dipping and spraying for the food products due to its antimicrobial properties. Chitosan has exhibited high antimicrobial activity against a wide variety of pathogenic and spoilage microorganisms, including fungi, and Gram-positive and Gram-negative bacteria. The present review aims to highlight various preparative methods and antimicrobial activity including the mechanism of the antimicrobial action of chitosan based films. The optimisation of the biocidic properties of these so called biocomposites films and role of biocatalysts in improvement of quality and shelf life of foods has been discussed. (C) 2008 Elsevier Ltd. All rights reserved