Antibacterial Activity and Physical Properties of Edible Chitosan Films Exposed to Low-pressure Plasma

Abstract

The challenge for food industry is developing gentle processes concept, which will prevent food spoilage and leave a food natural, minimally processed, fresh-like and safe. A new technique of food preservation could be usage of combined methods of green process, such as cold gas plasma with bioactive substances, and protective coatings. The aim of this study was to determine the antibacterial activity of chitosan films incorporated with lysozyme exposed to helium plasma treatment as well as evaluate their physical properties. The edible films have been prepared basing on low molecular weight chitosan by casting from lactic acid solution with water solution of lysozyme in three various concentrations (0, 0.5 and 1 %). Dried films were then modified by exposition on cold helium plasma treatment for 0, 5 and 10 min. Obtained films were tested against growth of Listeria monocytogenes, Yersinia enterocolitica and Pseudomonas fluorescens. In order to characterize chitosan-based films, their mechanical properties, theromogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), contact angle measurement, water vapour permeability (WVP) and scanning electron microscopy (SEM) were evaluated. The films with 1 % lysozyme incorporation enhanced the inhibition efficiency of chitosanbased films against gram-positive (L. monocytogenes) and gram-negative (P. fluorescens) bacteria, where reduction zones were 42.5 and 69.8 mm, respectively. Besides that, hydrolytic changes of chitosan chain caused by lysozyme activity were confirmed by TGA and DMTA. Contact angles and WVP of tested films were not significantly affected by helium plasma exposition, nor lysozyme dosage. Hydrophilic natures of chitosan-based films were confirmed by both tests.Microscopy image of cross-section structure was smooth and continuous due to lysozyme addition in film composition. Application of chitosan films incorporated with lysozyme and low-pressure plasma treatment could be used as innovative preservation method in a wide range of food products.

Effect of Film-Forming Alginate/Chitosan Polyelectrolyte Complex on the Storage Quality of Pork

“…The presented research confirmed the antimicrobial effects of chitosan on meat microbiota. Microbial colonization decreases with increasing concentration of chitosan, which was also confirmed by Ulbin-Figlewicz et al and Zimoch-Korzycka and Jarmoluk [ 30 , 31 ]. Three models of antibacterial action of chitosan have been proposed so far: (1) interaction between positively-charged chitosan molecules and negatively-charged microbial cell membranes; (2) binding of chitosan with microbial DNA; and (3) chelation of metals, suppression of spore elements and binding to essential nutrients to microbial growth [ 32 ].…”

Chitosan composite films: physicochemical characterization and their use as coating in papaya Maradol stored at room temperature

“…The force required to cause a rupture (TS, tensile strength) was determined by use a hand penetrometer (TR ® Italy) equipped with a tip of 5 mm in diameter, and estimated according to the equation TS (MPa) = N/mm The water vapor transmission rate (WVTR) was measured by the method suggested by Ulbin-Figlewicz et al (2014) and the water vapor permeability (WVP) was calculated with the formula: WVP (g / m s kPa) = (WVTR L)/DP, where "L" is the film thickness (m) and "DP" is the differential of partial pressure between the two sides of the biofilm (3.179 kPa). Solubility (S) was determined according to a method proposed by Wang et al (2011) and; the water content retained in equilibrium by the method described by Binsi et al (2013), which is reported as water sorption capacity (WSC).…”

Physicochemical and Antibacterial Properties of Carrageenan and Gelatine Hydrosols and Hydrogels Incorporated with Acidic Electrolyzed Water

“…Microbial spoilage causing deterioration of meat quality and loss of weight through surface evaporation are important subjects in the meat industry [1]. Various techniques have been proposed to eliminate or reduce bacterial population on meat and meat products.…”