Properties of polysaccharide-coated polypropylene films as affected by biopolymer and plasticizer types

Plasticized polysaccharide coatings on polypropylene (PP). film were prepared to evaluate the optical and tensile properties of the resulting coated films, as affected by biopolymer and plasticizer types, in order to develop a novel film structure of biopolymer coatings on common plastics intended for food packaging applications. Composite structures of PP film coated with several kinds of polysaccharides (MC, HPMC, chitosan, K-carrageenan, dextrin) and plasticizers (PG, glycerol, PEG, sucrose, sorbitol) were obtained through a simple casting method. High glossy surfaces were observed on the coated films with chitosan and K-carrageenan, with the sucrose-plasticized chitosan coating giving the highest gloss of 142.7GU. Biopolymers, but no plasticizers, exerted noticeable influence on the colour of the coated films. Chitosan- and K-carrageenan-coated PP films also showed greater transparency, tensile strength and elongation than the other coated films. Nisin-incorporated ic-carrageenan coatings on PP film exhibited significant bacterial growth inhibition against Lactobacillus plantarum. The results suggest that coatings based on chitosan and ic-carrageenan with proper plasticizers possess excellent visual and mechanical characteristics and have great potential for acting efficiently as antimicrobial agent carriers in active packaging systems. Copyright (C) 2004 John Wiley Sons, Ltd.