Thermal stability of bacteriocin nisin in polylactide-based films. (December 2018)

• Record Type: Journal Article
• Authors: Holcapkova, Pavlina; Hurajova, Anna; Bazant, Pavel; Pummerova, Martina; Sedlarik, Vladimir
• Is Part Of: Polymer degradation and stability. Volume 158(2018)
• Page Start: 31
• Page End: 39
• Publication Date: 2018-12
• Subjects: Nisin -- Polylactide -- Polyethylene glycol -- Thermal stability -- Biodegradable polymer -- Antibacterial -- Mass spectroscopy; Polymers -- Deterioration -- Periodicals; Stabilizing agents -- Periodicals; Polymères -- Dégradation -- Périodiques; Stabilisants -- Périodiques; 668.9
• DOI: 10.1016/j.polymdegradstab.2018.10.019
• Languages: English
• ISSNs: 0141-3910

Abstract

Abstract: This work investigates the thermal stability of bacteriocin nisin in polylactide (PLA) and polylactide/polyethylene glycol (PLA/PEG) blends at temperatures of 90 °C–180 °C. The samples were prepared by solvent cast technique and characterized according to their mechanical and thermal properties. Research on the thermal stability of nisin in the PLA and PLA/PEG systems was carried out by exposing the given films to various temperatures (90 °C, 120 °C, 160 °C, and 180 °C) for a duration of up to 48 h. Assessment of the antibacterial activity of the samples was carried out by the agar diffusion method against Micrococcus luteus, while structural analysis involved the use of high-performance liquid chromatography with mass detection. Structural changes in the polymer matrix were evaluated by gel permeation chromatography and scanning electron microscopy. The results showed that nisin retained almost 70% of its antimicrobial activity in the PLA matrix, even after treatment at 160 °C for 15 min. The presence of PEG significantly enhanced the degradation of nisin above 120 °C. Highlights: The issue related to natural based bacteriocin, nisin, as antibacterial modifier of polymers is discussed. Nisin stability and antibacterial activity in PLA was investigated at temperatures simulating the thermoplastic processing. Nisin incorporated in PLA matrix sustain its antibacterial activity even after exposure to temperatures corresponding to PLA melting point.