Characterization of the mechanical, chemical and thermal properties of antimicrobial (AM) starch-based films

Abstract

The present study evaluated the mechanical, chemical and thermal properties of starch based film incorporating lauric acid and chitosan. Starch-based film incorporating chitosan and lauric acid as antimicrobial agents was prepared by casting method. Chitosan has widely been used in antimicrobial films, to provide edible protective coating, dipping and spraying for food products due to its antimicrobial properties and good mechanical properties. The starch-based films also have antimicrobial properties that can extend shelf-life of the packed food. The effect of addition of lauric acid and chitosan into starch-based films on mechanical, chemical and thermal properties were characterized by transperancy test, tensile test, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC). The incorporation of chitosan and lauric acid into starch-based film enhanced the mechanical properties of starch-based films. Antimicrobial starch based film exhibited good flexibility. Tensile strength and percentage of elongation increased with the increasing chitosan content. SEM observations indicated that chitosan film was smooth and homogenous, while the starch film revealed characteristic granular pattern. The blend film exhibited an intermediate character with a slight microphase separation. Adding chitosan and lauric acid as antimicrobial agents in starch-based film indicated that there were interactions between the hydroxyl groups of starch and the amino groups of chitosan in the blend films as measured by FTIR.