0000000000390975
AUTHOR
P. Fernandez-saiz
Effects of chitosan films on the growth of Listeria monocytogenes, Staphylococcus aureus and Salmonella spp. in laboratory media and in fish soup.
The objective of this study was to assess the antimicrobial effectiveness of chitosonium acetate films on the growth of Listeria monocytogenes, Salmonella spp. and Staphylococcus aureus. The samples were tested in both laboratory conditions using Tryptone Soy Broth (TSB) and in a real food system using fish soup. The study was carried out at different temperatures (4, 12, and 37 degrees C) in order to discern the influence of such variables. Moreover, a sensory evaluation of the final product was performed as a parameter of consumer acceptance. The results showed a significant reduction of the bacterial growth, which greatly depended on the bacteria type, the temperature of incubation and t…
Antibacterial chitosan-based blends with ethylene–vinyl alcohol copolymer
Abstract This study reports for the first time about the formulation, morphology, water barrier and the antimicrobial activity of high and low molecular weight chitosonium-acetate based solvent-cast blends with ethylene–vinyl alcohol (EVOH) copolymers. The blends based on the low molecular weight chitosan grade showed enhanced phase morphology, transparency, enhanced water barrier properties, up to 86% water permeability reduction compared to pure chitosonium-acetate films, as well as excellent antimicrobial activity. When the fraction of low molecular weight chitosan exceeded the phase inversion in the blend, phase segregation became noticeable but good interfacial adhesion was still obser…
Optimization of the biocide properties of chitosan for its application in the design of active films of interest in the food area
The influence on biocide performance of some unprecedented physicochemical features of chitosan cast films such as film thickness, pH of the nutrient broth, film neutralization, film autoclave sterilization and temperature exposure were analyzed against Staphylococcus aureus and in some experiments also against Salmonella spp. The work demonstrates for the first time the influence of the release or positive migration of protonated glucosamine fractions from the biopolymer into the microbial culture as the responsible event for the antimicrobial performance of the biopolymer under the studied conditions. From the results, a reliable and reproducible method for the determination of the bacter…
Characterization of antimicrobial properties on the growth of S. aureus of novel renewable blends of gliadins and chitosan of interest in food packaging and coating applications
The biocide properties of chitosan-based materials have been known for many years. However, typical antimicrobial formulations of chitosan, mostly chitosonium salts, are known to be very water sensitive materials which may impair their use in many application fields such as food packaging or food coating applications. This first work reports on the development and characterization of the antimicrobial properties of novel fully renewable blends of chitosan with more water-resistant gliadin proteins isolated from wheat gluten. Chitosan release to the nutrient broth from a wide range of blends was studied making use of the ninhydrin method. The results indicated that both pure chitosan and its…
Chitosan films for the microbiological preservation of refrigerated sole and hake fillets
The effect of chitosan films for shelf-life extension of fresh fillets of hake (Merluccius merluccius) and sole (Solea solea) was evaluated over a 15-day storage at 4 ± 1 °C. Fish fillets wrapped in a chitosan matrix were individually packaged in air (AP) and under vacuum (VP). Microbiological analyses (total aerobic mesophilic bacteria, Pseudomonas, H2S-producing bacteria, lactic acid bacteria, Enterobacteriaceae and Listeria monocytogenes were carried out during the shelf-life. The microbial species were inhibited (p < 0.05) by the presence of chitosan films, especially under VP conditions. A significant (p < 0.05) increase of the lag phase and a reduction of the final microbial populatio…
Film-forming process and biocide assessment of high-molecular-weight chitosan as determined by combined ATR-FTIR spectroscopy and antimicrobial assays.
This pioneering study reported about the film-forming properties of high-molecular-weight chitosan as followed in situ by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, and has implications in fields such as biomedical, pharmaceutical, packaging, and coating applications. From the results, it was observed that immediately after dissolution in an acetic acid aqueous solution and subsequent casting over the ATR crystal, the formed carboxylate antimicrobial (-NH3+ -OOCH) species are not stable in the film formulation and become reduced over time; further assays confirmed previous research, which suggested that the presence and stability of these groups is stron…