Antimicrobial and Physical Properties of Chitosan Film as Affected by Solvent Types and Glycerol as Plasticizer

Abstract

This study aims to evaluate the influence of solvent acids and glycerol as plasticizer on the antimicrobial and physical properties of chitosan films. Three types of acids were used in the same concentration, e.g. 1% acetic acid, 1% citric acid and 1% lactic acid whereas glycerol was fixed on 10% (w/w). In terms of barrier properties, chitosan film obtained by citric acid as solvent showed the lowest water vapour transmission rate (WVTR) followed by chitosan film prepared with lactic acid and acetic acid. Concerning mechanical properties, chitosan film prepared with acetic acid exhibited the highest tensile strength and the lowest percentage elongation. The expected result was obtained where plasticized chitosan films had higher percentage elongation than the unplasticized one. In this study, disc and well diffusion method were used against bacteria, yeast and fungi to characterize antimicrobial activity of the obtained films. When the disc diffusion method was used, all of chitosan films showed an inhibition activity against E. coli, B. cereus and S. aureus whereas no inhibition against Penicillium sp. and Candida sp except chitosan film prepared with acetic acid that showed inhibition against Candida sp. The same result was observed by using well diffusion method with the exception of chitosan solutions prepared with acetic acid solution where they also showed inhibition activity against Penicillium sp. and Candida sp.