Zinc oxide nanoparticles (ZnONPs) have received considerable attention as an antibacterial agent particularly in the textile industry. In the present work a successful procedure for in situ growth of ZnONPs in textiles was developed. The results obtained showed that a combination of in situ synthesis and the sol–gel method promoted a uniform and dense adsorption of the nanoparticles both inside and on the surface of fabric fibres. The fabrics finished with ZnONPs have been investigated for antibacterial properties by the agar diffusion method and by the absorption method according to the ISO 20743:2013 standard and exhibited an antibacterial effect against methicillin resistant Staphylococcus aureus ATCC33591, Staphylococcus epidermidis ATCC1228, Staphylococcus aureus RN4220 and Propionibacterium acnes ATCC6919. Moreover, tests conducted with hydrogen peroxide suggested the involvement of reactive oxygen species, namely the involvement of hydrogen peroxide, in the antibacterial activity of the zinc oxide nanoparticles. Therefore, the synthesised nanoparticles showed great potential to be used as coatings for medical, cosmetic or sports fabrics.
Active packaging incorporated with natural extracts is a promising technology to extend shelf life of perishable food. Therefore, this study aimed to produce a bionanocomposite based on chitosan reinforced with sodium montmorillonite (MMT) and incorporated with ginger essential oil (GEO). In vitro activity was assessed through migration assay and antimicrobial study against foodborne bacteria. Phenolic compounds were diffused within 48 h of contact, and retained some of their antioxidant activity. Films demonstrated antimicrobial activity against both Gram-positive and -negative bacteria tested. The effect on the shelf life of fresh poultry meat was determined on samples wrapped in the biopolymers and stored under refrigeration for 15 days, through physicochemical and microbiological analyses. Compared to unwrapped poultry meat, samples wrapped in the bionanocomposites showed a reduction in microorganisms count of 1.2–2.6 log CFU/g, maintained color and pH values and thiobarbituric acid reactive substances (TBARS) index increased at a lower rate, extending fresh poultry meat shelf life. The incorporation of GEO enhanced the biopolymer activity, by reducing lipid oxidation and microbiological growth of the poultry meat. In contrast, reinforcement with MMT imprisoned the active compounds in the polymeric chain, hindering its activity. In conclusion, the bionanocomposites tested represent promising substitutes to commercial and unsustainable plastic films.
Novel bionanocomposite films of chitosan/montmorillonite (CS/MMT) activated with ginger essential oil (GEO) were produced and characterized in terms of their physical and morphological properties. The homogenization process led to a good interaction between the chitosan and the nanoparticles, however the exfoliation was diminished when GEO was incorporated. Film glass transition temperature did not statistically change with the incorporation of either MMT or GEO, however the value was slightly reduced, representing a relaxation in the polymer chain which corroborated with the mechanical and barrier properties results. Pristine chitosan films showed excellent barrier properties to oxygen with a permeability of 0.184 × 10−16 mol/m·s·Pa being reduced to half (0.098 × 10−16 mol/m·s·Pa) when MMT was incorporated. Although the incorporation of GEO increased the permeability values to 0.325 × 10−16 mol/m·s·Pa when 2% of GEO was integrated, this increment was smaller with both MMT and GEO (0.285 × 10−16 mol/m·s·Pa). Bionanocomposites also increased the UV light barrier. Thus, the produced bioplastics demonstrated their ability to retard oxidative processes due to their good barrier properties, corroborating previous results that have shown their potential in the preservation of foods with high unsaturated fat content.
22 November 2010 in Biofuels, Bioproducts and Biorefining