Preparation of Antimicrobial Membranes: Coextrusion of Poly(lactic acid) and Nisaplin in the Presence of Plasticizers

Abstract

Nisin is a naturally occurring antimicrobial polypeptide and is popularly used in the food and food-packaging industries. Nisin is deactivated at temperatures higher than 120 degrees C and, therefore, cannot be directly incorporated into poly(L-lactic acid) (PLA), a biomass-derived biodegradable polymer, by coextrusion because PLA melts at temperatures around 160 degrees C or above. However, PLA can remain in a melt state at temperatures below the T(m) in the presence of lactic acid or other plasticizers. In the present study, PLA was coextruded with lactic acid, or lactide, or glycerol triacetate at 160 degrees C. After the PLA was melted, the temperature of the barrels was reduced to 120 degrees C, and then Nisaplin, the commercial formulation of nisin, was added and the extrusion was continued. The resultant extrudates possess the capability to suppress the growth of the pathogenic bacterial Listeria monocytogenes , demonstrating a significant antimicrobial activity. The present study provides a simple method to produce PLA-based antimicrobial membranes. The method can also be used for the coextrusion of other heat-sensitive substances and thermoplastics with high melting temperature.

Influence of graphene on thermal degradation and crystallization kinetics behaviour of poly(lactic acid)

“…The T g value for PLA and PLA-GR nanocomposites does not change significantly. This indicates that the reinforcement of GR in the PLA matrix does not lead to degradation of PLA by stimulating the formation of shorter chain segments [15,16].…”

Characterization of antimicrobial poly(lactic acid)/poly(trimethylene carbonate) films with cinnamaldehyde

“…The bacteria were activated by vaccination to MHB. The antimicrobial test was determined by method of Liu et al with some modification [30]. Bacteria constant temperature cultivation condition was 37°C and 18-24 h. A glass test tube containing testing specimens (0.18-0.20 g for each) was filled with 10 mL of broth.…”

Development of Antimicrobial Coatings for Improving the Microbiological Safety and Quality of Shell Eggs

“…Previous studies in our laboratory have demonstrated that antimicrobial films or coatings with U.S. Food and Drug Administration generally recognized as safe (GRAS) antimicrobials are effective in reducing pathogens in various foods (26,27,29,30,38,39). (29).…”