The antimicrobial, mechanical, physical and structural properties of chitosan-gallic acid films

The antimicrobial, mechanical, physical and structural properties of chitosan-gallic acid films. Manuscript version of a work that was subsequently published in LWT – Food Science and Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in LWT – Food Science and Abstract 16 Chitosan films incorporated with various concentrations of gallic acid were prepared 17 and investigated for antimicrobial, mechanical, physical and structural properties. Four 18 bacterial strains that commonly contaminate food products were chosen as target bacteria 19 to evaluate the antimicrobial activity of the prepared gallic acid-chitosan films. The 20 incorporation of gallic acid significantly increased the antimicrobial activities of the films 21 against Escherichia coli, Salmonella typhimurium, Listeria innocua and Bacillus subtilis. 22 Chitosan films incorporated with 1.5 g/100 g gallic acid showed the strongest 23 antimicrobial activity. It was also found that tensile strength (TS) of chitosan film was 24 significantly increased when incorporating 0.5 g/100 g gallic acid. Inclusion of 0.5 g/100 25 g gallic acid also significantly decreased water vapor permeability (WVP) and oxygen 26 permeability (OP). Microstructure of the films was investigated by Fourier transform 27 infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) and it was found 28 that gallic acid was dispersed homogenously into the chitosan matrix.