Papers by José Carlos Guirado Moreno
Sensors and Actuators B: Chemical
Food Packaging and Shelf Life
There is a strong need to reduce food waste while maintaining the quality of packaged food. Thus,... more There is a strong need to reduce food waste while maintaining the quality of packaged food. Thus, we have prepared a new fully organic and metal-free antimicrobial polymer, with the aim of increasing both the shelf life and safety of packaged meat. This antimicrobial polymer is based on widely available commercial acrylic monomers with covalently linked vanillin motifs, which are naturally occurring essential oils with antimicrobial characteristics. The film-shaped antibacterial polymeric material shows antibacterial activity for Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes with an R parameter of up to 3.18, 3.37 and 2.00 and inhibition % of up to 99.95%, 99.96%, and 99.02%, respectively. To show the potential of these materials, we conducted a proof of concept experiment in which the antimicrobial polymer film was used as an absorbent food pad. The results show that the use of the antimicrobial polymer film can increase the shelf life of a packaged meat product by 50%. Since the antimicrobial activity is based on a covalently anchored group, there is no antimicrobial agent diffusion, and the antimicrobial activity persists beyond the first use because it is easily washable and reusable for at least 10 cycles.
Food Chemistry
Glucose oxidase (GOX) and catalase (CAT) regulate the amount of H2O2 in honey, by generating or c... more Glucose oxidase (GOX) and catalase (CAT) regulate the amount of H2O2 in honey, by generating or consuming it, so they are related to the antibacterial and antioxidant activity of honey. However, their activities are hardly analysed, since the process requires a previous dialysis that is non-selective, very time-consuming (>24 h), ecounfriendly (>6L of buffer) and expensive. This research shows the design and performance of a material that selectively removes the actual interferents. The film-shaped-polymer is immersed for 90́ within a honey solution (12.5 mL of buffer), where it interacts exclusively with 1,2-dihydroxybenzenes, which we proved to be the real interferents (the material contains motifs derived from phenylboronic acid to interact with 1,2-diols). Polymeric chains favour condensation to occur exclusively with 1,2-dihydroxybenzenes, excluding monosaccharides. The interferents' removal using our designed polymer is selective, low cost (1.42€ per test), rapid and eco-friendly (saves 6L of buffer and 20.5 h of experimental workout per sample).
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
The synthesis and preparation of 12 chromogenic polymers used to build an intelligent label for s... more The synthesis and preparation of 12 chromogenic polymers used to build an intelligent label for security paper applications are described. The process involves coating paper sheets with the polymers. Depending on the number of different polymers used in a combinatory way, a maximum of 12 12 combinations is possible, thus creating a matrix that is practically impossible to counterfeit. Currently, most anticounterfeiting proposals for paper-based packaging and documents involve some sort of verification under ultraviolet radiation, and the requirement of additional equipment often relegates the end-user to a passive role. In contrast, in our approach, the combination of sensory polymers in an array gives rise to an invisible label, i.e., an owner cryptographic key, which becomes visible upon scattering a nitrite solution (e.g., spraying or using an impregnated foam roller) over the printed label on the security paper. For this purpose, a monomer containing an aromatic primary amino group and another with an activated aromatic ring are covalently bonded to a polymer with high affinity toward paper, consisting essentially of units of methyl methacrylate and 1-vinyl-2-pyrrolidone. Subsequently, the paper samples are coated with the resulting sensory chromogenic polymer. By spraying, painting, or staining an aqueous acid solution of NaNO 2 (at least 1.20 g/L) and the chromogenic polymers, a well-defined color appears, because of the formation of an azo compound. This process provides users with a quick and facile authentication method without additional equipment and without affecting paper strength.
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Papers by José Carlos Guirado Moreno