| Summary: | 碩士 === 國立中興大學 === 食品暨應用生物科技學系所 === 107 === This research is mainly focused on preparing gallic acid (GA) coated, antimicrobial, active packaging, and low density polyethylene (LDPE) films by capacitively coupled plasma. In order to produce antibacterial packaging, surface modification of LDPE was performed by plasma treatment and the film was immediately immersed in different concentrations of GA solution. The effects of surface modification and antimicrobial activity of this film were studied. The surface morphology of the film was analyzed by SEM. It was observed that plasma treatment successfully modified the surface of LDPE. Besides, as the GA concentration increase, the surface roughness becoming smoother. Additionally, through plasma treatment, GA coated LDPE film exhibited antibacterial activity against Gram-negative bacterium Escherichia coli and Gram-positive bacterium Staphylococcus aureus and 1% GA or above coated group shows the most effective antibacterial activity. The second part of the experiment is to continue the first stage of the results, combined with a natural antibacterial agent - Chitosan (CS) to make a composite antibacterial packaging film, and applied to the preservation of Tilapia fillets. It can be seen from the results that the group coated with GA, CS and CS-GA can delay the growth of microorganisms compared with the control group, thereby delaying the formation of VBN. The results of TBA value showed that the control group reached the highest on day 14, while the GA and CS-GA groups were 0.2630 and 0.2307 ppm respectively, indicating that the treatment group could delay lipid oxidation of Tilapia fillets. Based on the results of this study, the film coated with the preservative after plasma treatment can prolong the shelf life of the Tilapia fillets by delaying microbial growth and lipid oxidation.
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