Properties and antimicrobial activities of starch-sodium alginate composite films incorporated with sodium dehydroacetate or rosemary extract

摘要

Antimicrobial films were prepared with oxidized and acetylated corn starch-sodium alginate by incorporating sodium dehydroacetate or rosemary extract. Films incorporated with sodium dehydroacetate ≥ 0.1% or rosemary extract ≥ 0.3% had an anti-Escherichia coli effect. Aspergillus niger could be effectively inhibited by the incorporation of sodium dehydroacetate ≥ 0.3%. Rosemary extract showed no inhibitory effect on Aspergillus niger. Sodium dehydroacetate and rosemary extract reduced the tensile strength and elongation at break, and increased the water vapor permeability of the films. Sodium dehydroacetate made the films more greenish-yellow with the increase of sodium dehydroacetate concentration. The color of the films became darker and more reddish-yellow as rosemary extract was increased. Fourier transform infrared (FTIR) spectra analysis revealed that sodium dehydroacetate and rosemary extract reduced starch crystallinity. The surface of the films became rougher as a result of an addition of sodium dehydroacetate and rosemary extract. These findings had potential applications in prolonging food shelf life based on different needs.