Comprehensive evaluation and characterization of antimicrobial based packaging film

This paper evaluates the performance of biopolymer-based antimicrobial packaging solutions which designed to enhance food safety and extend shelf life. The films were subjected to a range of physico-chemical and thermomechanical tests, including mechanical properties (tensile strength), moisture absorbency, biodegradability, water vapor permeability, and antimicrobial activity. Incorporating chitosan at various concentrations (6% w/w, 12% w/w, and 18% w/w) significantly improved the films' ability to inhibit microbial growth. The highest reduction was observed at 12% chitosan, achieving a 70% reduction in Escherichia coli (1.0 × 10^⁶ CFU/mL to 3.0 × 10^⁵ CFU/mL) and a 55% reduction in Staphylococcus aureus (1.2 × 10^6 CFU/mL to 5.4 × 10^⁵ CFU/mL) (using Eq. 6). In contrast, at 18% chitosan, effectiveness declined, stabilizing at a 68% reduction for Staph. aureus (approximately 4.8 × 10^⁵ CFU/mL), indicating that higher concentrations may hinder antimicrobial penetration and promote bacterial aggregation. The inclusion of filler (clay particles) enhanced thermal stability and mechanical integrity. The films were formulated based on specific ratios of clay to starch-chitosan (1:1:6, 7:5:12, and 10:5:18 w/w) and plasticizer to starch-chitosan (5:1:6, 6:1:12, and 7:1:18 w/w). Comprehensive analyses, including TGA-DSC, tensile strength, barrier properties, moisture absorbency, biodegradability, and antibacterial activity against E. coli and Staph. aureus, were performed. The optimal film was identified with a clay-chitosan-plasticizer ratio of 7:2:5:12, achieving a mechanical strength of 4.96 ± 0.12 MPa, a water vapor transmission rate of 3.96 ± 0.12%, and a degradation rate of 44.76 ± 0.32%. These findings suggest that these antimicrobial films are promising packaging solutions for safer food products.

The online version contains supplementary material available at 10.1007/s13197-024-06174-y.