Investigation of the release rate and physicochemical, antioxidant and antimicrobial properties of starch films containing cinnamon essential oil and chitosan nanofiber

Abstract

In this research, antioxidant active nanocomposite film based on starch was prepared by incorporation of cinnamon essential oil (CEO) and chitosan nanofibers (CHNF). Both of the additives were added at concentrations of 0, 2.5 and 5 % and their effect on barrier, mechanical and morphological characteristics and antioxidant properties were investigated. Also, the release rate of CEO from nanocomposites was studied at two temperatures. With adding CEO water vapor permeability (WVP) was increased, but moisture absorption was decreased. However, CHNF caused to significant decrease of both parameters. CEO decreased the tensile strength of starch films but CHNF increased tensile strength and decreased elongation of films. Results of XRD and FTIR tests approved the homogenous distribution of CEO and CHNF in starch matrix. Also they approved that there are no structural changes and no new interactions after addition of CEO and CHNF to starch film. CEO especially in the concentration of 5% significantly increased the antioxidant activity of starch film, but CHNF decreased its antioxidant activity. Investigation of release rate of essential oil into ethanol (96 %) revealed that by increasing temperature from 4 to 25 °C, the release rate was significantly increased in all samples. The films containing CEO had the highest release rate and its release was controlled after incorporation of CHNF. Generally, the results of this research indicated that by addition of CEO and CHNF to starch film can prepare films with good properties and controlled release characteristics.