Dr. José Jesús Benítez Jiménez

Plasticized cellulose bioplastics with antioxidant and antimicrobial properties were prepared by blending cellulose and glycerol in a mixture of trifluoroacetic acid and trifluoroacetic anhydride, adding a solution of beeswax in chloroform, and subsequent drop-casting. Optical, chemical, structural, mechanical, thermal, and hydrodynamic properties were fully characterized. In addition, the biodegradability in seawater was investigated by determination of the biological oxygen demand. The incorporation of beeswax ruled out the transparency and UV blocking, modified the main mechanical parameters, and improved the thermal stability and the antioxidant capacity, as well as the hydrodynamic and barrier properties. In general, these features were comparable to those of common petroleum-based food packaging plastics. Such changes were explained by the incorporation of beeswax into the polymer matrix, as determined by infrared spectroscopy and X-ray diffraction. These cellulose-beeswax bioplastics were evaluated as viable food packaging materials by determination of the overall migration by using Tenax® as a dry food simulant, oxygen permeability at different relative humidities, measurement of antimicrobial activity against Escherichia coli and Bacillus cereus, and through preservation of fresh-cut pear slices, showing results similar to those obtained by using low-density polyethylene. © 2024 The Authors

The plant cuticle is located at the interface of the plant with the environment, thus acting as a protective barrier against biotic and abiotic external stress factors, and regulating water loss. Additionally, it modulates mechanical stresses derived from internal tissues and also from the environment. Recent advances in the understanding of the hydric, mechanical, thermal, and, to a lower extent, optical and electric properties of the cuticle, as well as their phenomenological connections and relationships are reviewed. An equilibrium based on the interaction among the different biophysical properties is essential to ensure plant growth and development. The notable variability reported in cuticle geometry, surface topography, and microchemistry affects the analysis of some biophysical properties of the cuticle. This review aimed to provide an updated view of the plant cuticle, understood as a modification of the cell wall, in order to establish the state-of-the-art biophysics of the plant cuticle, and to serve as an inspiration for future research in the field. © 2024 The Author(s). New Phytologist © 2024 New Phytologist Foundation.

Bio-based lacquers prepared from an underutilized tomato processing residue such as pomace have been investigated as sustainable alternatives to bisphenol A (BPA)-based coatings for metal food packaging. The fabrication methodology consisted of a two-step process: spray-coating of a paste of the lipid fraction of tomato pomace with a mixture ethanol:H2O (3:1, v:v) on common metal substrates, used for food canning, such as aluminum (Al), chromium-coated tin-free steel (TFS), and electrochemically tin-plated steel (ETP), followed by the self melt-polycondensation of such lipid fraction. The polymerization reaction was conducted at 200 °C for different times (10, 20, 30, 40, 50, and 60 min) and was monitored by specular infrared spectroscopy, resulting in maximum degrees of esterification of ∼92% for Al and ∼85% for TFS and ETP substrates. The anticorrosion performance of the coatings was studied by electrochemical impedance spectroscopy at different immersion times (time intervals of 2–5 h during an overall stability test up to 170 h) in an aqueous solution of 1 wt% NaCl. The degree of polymerization and the physical properties of the coatings showed a strong dependence on the metal substrate used. In general, the best results were found for tomato pomace-based lacquers applied on aluminum, achieving higher mechanical strength (critical load of 1739 ± 198 mN for Al, 1078 ± 31 mN for ETP, and 852 ± 206 mN for TFS), hydrophobicity (water contact angle ∼95° for Al, ∼91° for ETP, and ∼88° for TFS), and improved anticorrosion performance (coating resistance of 0.7 MΩcm2 after 170 h of immersion for Al, 0.7 MΩcm2 after 70 h of immersion for TFS, and negligible coating resistance for ETP). In view of the technical innovation proposed in the present paper, the estimation of the environmental sustainability of the process has been considered relevant to fit the circular economy target. For this purpose, a life cycle analysis (LCA) was applied to the overall process, revealing multiple advantages for both the environment and human health. © 2022 The Authors

Tridecafluorononanoic acid (TFNA), a C6-fluorinated carboxylic acid, was esterified with cellulose at different molar ratios (0:1, 1:1, 2:1, and 3:1) in a trifluoroacetic acid (TFA):trifluoroacetic anhydride (TFAA):CHCl3 (2:1:1, vv) solvent mixture. Free-standing films were obtained for all formulations and are presented as alternatives to composites and blends of paper with fluorinated molecules. Mechanical properties were investigated by tensile tests, and a plasticizer effect of fluorinated chains was observed. Interestingly, the wettability of these new cellulose derivatives was similar or even better than other common cellulose derivatives and fluorinated polymers employed in food packaging. Hydrodynamic properties were also improved by addition of TFNA, resulting in materials with water vapor permeability values comparable to other cellulose-based food packaging materials. In addition, films with the higher amounts of TFNA showed the required oil resistance for papers used in food packaging applications, as determined by the Kit Test. Finally, the biodegradation of these C6-fluorinated cellulose esters, assessed by biological oxygen demand (BOD) in seawater, was higher than typical bio-based polymers used in food packaging. The bioplastic synthesized at a molar ratio 1:1 (TFNA:cellulose) showed excellent performances in terms of greaseproof, hydrophobicity, ductility, and biodegradability, representing a sustainable alternative to typical plastics used in food packaging. © 2022 The Authors

Polylactide-based materials represent a promising bio-based alternative to traditional food packaging polymers. However, their widespread use is still limited due to significant drawbacks, such as brittleness, high gas permeability, and biodegradability only under specific conditions. This work introduces fully bio-based Triphenyl Acetic Glyceroate (TPAG), synthesized through a solvent-free and mild conditions valorization of glycerol and phenylacetic acid, as a polylactide (PLA) plasticizer and multiple property-enhancer for extending foodstuff shelf-life. After optimizing TPAG synthesis and confirming its structure through FT-IR and NMR, PLA-based films are prepared at different TPAG contents (0, 5, 10, and 20 phr). Detailed investigations of the films’ thermal, mechanical, optical, hydrodynamic, barrier, antioxidant, antibacterial, migration, and biodegradation characteristics are carried out. TPAG shows a significant plasticizing effect while maintaining high transparency and improving PLA’s antioxidant, antibacterial and UV-blocking activities. Moreover, a notable lowering in oxygen and water vapor transmission rate is detected, revealing water vapor barrier properties closer to LDPE. Migration tests verify the material’s compliance with European regulations up to 10 phr, and BOD assessments in seawater indicate improved biodegradability. Fresh food preservation is evaluated on pear slices, showing limited variation of color, acidity, antioxidant power, and weight loss comparable to LDPE-based commercial packaging.