Regulating the physicochemical properties of chitosan films through concentration and neutralization

Authors: XUE, JIE - Jiangnan University; LIU, KUN - Jiangnan University; CHANG, WEI - Jiangnan University; Chiou, Bor-Sen; CHEN, MAOSHEN - Jiangnan University; LIU, FEI - Jiangnan University

Submitted to: Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/3/2022
Publication Date: 6/5/2022
Citation: Xue, J., Liu, K., Chang, W., Chiou, B., Chen, M., Liu, F. 2022. Regulating the physicochemical properties of chitosan films through concentration and neutralization. Foods. 11(11). Article 1657. https://doi.org/10.3390/foods11111657.
DOI: https://doi.org/10.3390/foods11111657

Interpretive Summary: Chitosan films have excellent film forming and antibacterial properties and have been used in food packaging applications. However, the residual acetic acid left over during film preparation imparts an acidic flavor. Also, acetic acid absorbs water, making the chitosan films weaker and more permeable to water vapor. In this study, we examined the effects of chitosan concentration and neutralization of acetic acid on physical properties of chitosan films. Before neutralization, films with higher chitosan concentrations (lower acetic acid concentrations) had higher strength and better water vapor barrier properties. After neutralization, the chitosan concentration had no effect on film strength and barrier properties. However, the neutralized films had greater strength and better barrier properties than those that were not neutralized. These results indicated that neutralization of chitosan films can be used to improve their film properties for packaging applications.

Technical Abstract: Chitosan films had excellent properties and could be used in many potential applications. They could be easily made into films and had antibacterial properties. However, the production and application of chitosan films were limited by their strong residual acetic acid taste, weak mechanical properties and poor water vapor barrier properties. In this study, the effects of the chitosan concentration in the film-forming solutions and the neutralization treatment on the physicochemical properties of chitosan films were examined. The results showed that the chitosan concentration affected the mechanical and barrier properties of chitosan films without neutralization treatment. This was mainly due to the low acetic acid contents in chitosan films after drying. Acetic acid behaved like a plasticizer within chitosan films by making the network structure in the films looser. After neutralization, the chitosan films showed improvements in properties, with the chitosan concentration in the film-forming solutions having little effect. Chitosan films after neutralization showed no residual acetic acid. Thus, neutralization could effectively improve the performance of chitosan films.