Food aroma mass transport properties in renewable hydrophilic polymers

[EN] The sorption and transport properties of gliadin and chitosan films with respect to four representative food aroma components (ethyl caproate, 1-hexanol, 2-nonanone and α-pinene) have been studied under dry and wet environmental conditions. The partition coefficients (K) of the selected volatiles were also obtained using isooctane and soybean oil as fatty food simulants. The results showed that gliadin and chitosan films have very low capacities for the sorption of volatile compounds, and these capacities are influenced by the nature of the sorbate, the environmental relative humidity and the presence of glycerol as a plasticizer in the polymeric matrix. The volatile compounds also present a low partitioning in the biopolymer film/food stimulant system. Given the low levels of interaction observed with the volatiles, gliadin and chitosan films are of potential interest for the packaging of foods in which aroma is one of the most important quality attributes Highlights ► Sorption kinetics and equilibrium partitioning of food aroma compounds in bioplastics. ► Gliadin and chitosan films show low sorption and partitioning capacities of food aroma compounds. ► Sorption and diffusion depend on volatile chemical structure, film composition and moisture. ► Great potential in packaging of foods in which aroma is an important quality attribute.This research has been supported from the Spanish Ministry of Science and Innovation through the Projects AGL2006-02176, AGL2009-08776 and FUN-C-FOOD Consolider Ingenio. The authors would like to thank A.P. Mac Cabe for critical reading of the manuscript.Balaguer, MP.; Gavara Clemente, R.; Hernández Muñoz, P. (2012). Food aroma mass transport properties in renewable hydrophilic polymers. Food Chemistry. 130(4):814-820. https://doi.org/10.1016/j.foodchem.2011.07.052S814820130

Reversible Covalent Immobilization of Cinnamaldehyde on Chitosan Films via Schiff Base Formation and Their Application in Active Food Packaging

[EN] In this work, cinnamaldehyde was reversibly anchored to chitosan films via imino-covalent bonding. The Schiff base was synthesized in solid phase employing neutralized chitosan films immersed in acidified 95 % (v/v) ethanolic solution in which the aldehyde was dissolved. The substitution degree (%) of cinnamaldehyde to the amine group was close to 70 %. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) analysis revealed the formation of the chitosan-cinnamaldehyde Schiff base. The hydrolysis of the imino bond and subsequent release of cinnamaldehyde were studied after the films had been subjected to different combinations of temperature/time treatments simulating food preservation methods. The amount of aldehyde that remained covalently attached to the films was monitored by ATR-FTIR, and the substitution degree was determined by elemental analysis. Surface contact angle and colour parameters of cinnamaldehyde-imine-chitosan films and these films subjected to different treatments were also evaluated. The antimicrobial properties of chitosan-Schiff base films were tested in vitro against Staphylococcus aureus and Escherichia coli and in milk inoculated with Listeria monocytogenes. The antimicrobial activity varied depending on the treatment applied and consequently the degree of imino bond hydrolysis achieved and cinnamaldehyde released. Films of Schiff base-chitosan derivative subjected to different time/temperature treatments inhibited the growth of L. monocytogenes for 12 days under refrigeration conditions, which may extend the microbiological shelf life of such products. Sensory analysis of milk in contact with the films showed that a cinnamon smell does not cause any rejection among potential consumers. These novel films could be used in the design of antimicrobial food packaging and in various other technological areas where sustained-release systems are requiredThe authors wish to thank the financial support provided by the Spanish Ministry of Science and Innovation (project AGL2012-39920-C03-01) and Spanish Research Council (CSIC, JAE-Predoc L.H. fellowship).Higueras-Contreras, L.; Lopez-Carballo, G.; Gavara Clemente, R.; Hernández-Muñoz, P. (2015). Reversible Covalent Immobilization of Cinnamaldehyde on Chitosan Films via Schiff Base Formation and Their Application in Active Food Packaging. Food and Bioprocess Technology. 8(3):526-538. https://doi.org/10.1007/s11947-014-1421-8S52653883Abreu, F. O., Oliveira, E. F., Paula, H. C., & de Paula, R. (2012). Chitosan/cashew gum nanogels for essential oil encapsulation. Carbohydrate Polymers, 89(4), 1277–1282.Balaguer, M. P., Gómez-Estaca, J., Gavara, R., & Hernández-Muñoz, P. (2011a). Biochemical properties of bioplastics made from wheat gliadins cross-linked with cinnamaldehyde. Journal of Agricultural and Food Chemistry, 59(24), 13212–13220.Balaguer, M. P., Gómez-Estaca, J., Gavara, R., & Hernández-Muñoz, P. (2011b). Functional properties of bioplastics made from wheat gliadins modified with cinnamaldehyde. Journal of Agricultural and Food Chemistry, 59(12), 6689–6695.Belletti, N., Lanciotti, R., Patrignani, F., & Gardini, F. (2008). Antimicrobial efficacy of citron essential oil on spoilage and pathogenic microorganisms in fruit-based salads. Journal of Food Science, 73(7), M331–M338.Burt, S. (2004). Essential oils: their antibacterial properties and potential applications in foods—a review. International Journal of Food Microbiology, 94(3), 223–253.Cocchiara, J., Lalko, J., Lapczynski, A., Letizia, C. S., & Api, A. M. (2005). Fragrance material review on cinnamaldehyde. Food and Chemical Toxicology, 43(6), 867–923.Coma, V., Martial-Gros, A., Garreau, S., Copinet, A., Salin, F., & Deschamps, A. (2002). Edible antimicrobial films based on chitosan matrix. Journal of Food Science, 67(3), 1162–1169.Damodaran, S., & Kinsella, J. E. (1980). Flavor protein interactions. Binding of carbonyls to bovine serum-albumin: thermodynamic and conformational effects. Journal of Agricultural and Food Chemistry, 28(3), 567–571.dos Santos, J. E., Dockal, E. R., & Cavalheiro, E. T. G. (2005). Synthesis and characterization of Schiff bases from chitosan and salicylaldehyde derivatives. Carbohydrate Polymers, 60(3), 277–282.Doyle, M. P., & Beuchat, L. R. (2007). Food microbiology: fundamentals and frontiers. Washington: ASM Press.Fleming, D. W., Cochi, S. L., MacDonald, K. L., Brondum, J., Hayes, P. S., Plikaytis, B. D., Holmes, M. B., Audurier, A., Broome, C. V., & Reingold, A. L. (1985). Pasteurized milk as a vehicle of infection in an outbreak of listeriosis. New England Journal of Medicine, 312(7), 404–407.Foster, L. J. R., & Butt, J. (2011). Chitosan films are not antimicrobial. Biotechnology Letters, 33(2), 417–421.Gallstedt, M., & Hedenqvist, M. S. (2006). Packaging-related mechanical and barrier properties of pulp-fiber-chitosan sheets. Carbohydrate Polymers, 63(1), 46–53.Gill, A., & Holley, R. (2004). Mechanisms of bactericidal action of cinnamaldehyde against Listeria monocytogenes and of eugenol against L. monocytogenes and Lactobacillus sakei. Applied and Environmental Microbiology, 70(10), 5750–5755.Guinesi, L. S., & Cavalheiro, E. T. G. (2006). Influence of some reactional parameters on the substitution degree of biopolymeric Schiff bases prepared from chitosan and salicylaldehyde. Carbohydrate Polymers, 65(4), 557–561.Guo, Z. Y., Xing, R. E., Liu, S., Zhong, Z. M., Ji, X., Wang, L., & Li, P. C. (2007). Antifungal properties of Schiff bases of chitosan, N-substituted chitosan and quaternized chitosan. Carbohydrate Research, 342(10), 1329–1332.Gutierrez, J., Barry-Ryan, C., & Bourke, R. (2008). The antimicrobial efficacy of plant essential oil combinations and interactions with food ingredients. International Journal of Food Microbiology, 124(1), 91–97.Higueras, L., López-Carballo, G., Cerisuelo, J. P., Gavara, R., & Hernández-Muñoz, P. (2013). Preparation and characterization of chitosan/HP-beta-cyclodextrins composites with high sorption capacity for carvacrol. Carbohydrate Polymers, 97(2), 262–268.Holley, R. A., & Patel, D. (2005). Improvement in shelf-life and safety of perishable foods by plant essential oils and smoke antimicrobials. Food Microbiology, 22(4), 273–292.Hosseini, S., Zandi, M., Rezaei, M., & Farahmandghavi, F. (2013). Two-step method for encapsulation of oregano essential oil in chitosan nanoparticles: preparation, characterization and in vitro release study. Carbohydrate Polymers, 95(1), 50–56.Huang, Z.H., Wan, D.C. & Huang, J.L. (2001). Hydrolysis of Schiff bases promoted by UV light. Chemistry Letters, (7), 708–709.Inukai, Y., Chinen, T., Matsuda, T., Kaida, Y., & Yasuda, S. J. (1998). Selective separation of germanium (IV) by 2,3-dihydroxypropylchitosan resin. Analytica Chimica Acta, 371(2–3), 187–193.Ji, C., & Shi, J. (2013). Thermal-crosslinked porous chitosan scaffolds for soft tissue engineering applications. Materials Science and Engineering: C, 33(7), 3780–3785.Jin, X., Wang, J., & Bai, J. (2009). Synthesis and antimicrobial activity of the Schiff base from chitosan and citral. Carbohydrate Research, 344(6), 825–829.Junttila, J. R., Niemela, S. I., & Hirn, J. (1988). Minimum growth temperatures of Listeria monocytogenes and non-haemolytic Listeria. Journal of Applied Bacteriology, 65(4), 321–327.Kasaai, M. R., Arul, J., Chin, S. L., & Charlet, G. (1999). The use of intense femtosecond laser pulses for the fragmentation of chitosan. Journal of Photochemistry and Photobiology, A: Chemistry, 120(3), 201–205.Kirdant, A. S., Shelke, V. A., Shankarwar, S. G., Shankarwar, A. G., & Chondhekar, T. K. (2011). Kinetic study of hydrolysis of N-salicylidene-m-methyl aniline spectrophotomerically. Journal of Chemical and Pharmaceutical Research, 3(4), 790–796.Kuhn, J., Considine, T., & Singh, H. (2006). Interactions of milk proteins and volatile flavor compounds: implications in the development of protein foods. Journal of Food Science, 71(5), R72–R82.Li, X., Shao, T., Shi, Q., & Hu, M. (2013). A diaryl Schiff base as a photo- and pH-responsive bifunctional molecule. RSC Advances, 3(45), 22877–22881.Lovett, J., Francis, D. W., & Hunt, J. M. (1987). Listeria monocytogenes in raw milk: detection, incidence, and pathogenicity. Journal of Food Protection, 50(3), 188–192.Mohamad, A. (2013). Reactivity of base catalysed hydrolysis of 2-pyridinylmethylene-8-quinolinyl-Schiff base iron(II) iodide complexes: solvent effects. Chemické zvesti, 67(4), 464–476.Muhamad, S. G. (2011). First photolysis of benzidine Schiff base in non aqueous solvents. International Journal of Chemistry, 1(3), 142–145.Muriel-Galet, V., López-Carballo, G., Gavara, R., & Hernández-Muñoz, P. (2012). Antimicrobial food packaging film based on the release of LAE from EVOH. International Journal of Food Microbiology, 157(2), 239–244.Nazzaro, F., Fratianni, F., De Martino, L., Coppola, R., & De Feo, V. (2013). Effect of essential oils on pathogenic bacteria. Pharmaceuticals, 6(12), 1451–1474.Renault, F., Sancey, B., & Crini, G. (2009). Chitosan for coagulation/flocculation processes—an eco-friendly approach. European Polymer Journal, 45(5), 1337–1348.Sashiwa, H., & Aiba, S. I. (2004). Chemically modified chitin and chitosan as biomaterials. Progress in Polymer Science, 29(9), 887–908.Shahidi, F., Arachchi, J. K. V., & Jeon, Y. J. (1999). Food applications of chitin and chitosans. Trends in Food Science & Technology, 10(2), 37–51.Vallapa, N., Wiarachai, O., Thongchul, N., Pan, J. S., Tangpasuthadol, V., Kiatkamjornwong, S., & Hoven, V. P. (2011). Enhancing antibacterial activity of chitosan surface by heterogeneous quaternization. Carbohydrate Polymers, 83(2), 868–875.Wang, J. T., Lian, Z. R., Wang, H. D., Jin, X. X., & Liu, Y. J. (2012). Synthesis and antimicrobial activity of Schiff base of chitosan and acylated chitosan. Journal of Applied Polymer Science, 123(6), 3242–3247.Zivanovic, S., Chi, S., & Draughon, A. F. (2005). Antimicrobial activity of chitosan films enriched with essential oils. Journal of Food Science, 70(1), M45–M51

Antimicrobial Effectiveness of Lauroyl Arginate Incorporated into Ethylene Vinyl Alcohol Copolymers to Extend the Shelf-Life of Chicken Stock and Surimi Sticks

[EN] This study was designated to determine the antimicrobial effect of ethyl-N-alpha-dodecanoyl-l-arginate hydrochloride (LAE) incorporated into ethylene vinyl alcohol copolymers (EVOH) films on chicken stock and ready-to-eat surimi sticks. Firstly, the effect of LAE against Listeria monocytogenes and Escherichia coli was studied by using flow cytometry and scanning electron microscopy. Next, film-forming solutions of ethylene vinyl alcohol copolymers EVOH29 and EVOH44 (29 and 44 % molar percentage of ethylene, respectively) containing 0, 5 and 10 % w/w of LAE were cast into films. Several experiments were conducted to determine the antimicrobial activity of the films in vitro and also in vivo with the above-mentioned food products. The outcome of the tests showed a high impact on the viability of bacteria treated with LAE, with dramatic damage to the membrane. The films were able to inhibit the microbiota of the food products studied for 10 days under storage at 4 A degrees C, showing a significant antibacterial effect against L. monocytogenes and E. coli. These films show great potential as systems for sustained release of active molecules to improve the safety and quality of packaged food products.The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, project AGL2012-39920-C03-01, and fellowship funding for V. M.-G.Muriel Galet, V.; Lopez-Carballo, G.; Gavara Clemente, R.; Hernández-Muñoz, P. (2015). Antimicrobial Effectiveness of Lauroyl Arginate Incorporated into Ethylene Vinyl Alcohol Copolymers to Extend the Shelf-Life of Chicken Stock and Surimi Sticks. Food and Bioprocess Technology. 8(1):208-216. https://doi.org/10.1007/s11947-014-1391-xS20821681Adams MR & Moss MO (2008) Food microbiology. The Royal Society of Chemistry Cambrigde, UKAppendini, P., & Hotchkiss, J. H. (2002). Review of antimicrobial food packaging. Innovative Food Science and Emerging Technologies, 3(2), 113–126.Bakal G & Diaz A (2005) The lowdown on lauric arginate. Food quality(Feb./March), 60-61.Fellows PJ (2009) Food processing technology: principle and practice. Third edn.Guo, M., Jin, T., Wang, L., Scullen, O. J., & Sommers, C. (2014). Antimicrobial films and coatings for inactivation of Listeria innocua on ready-to-eat deli turkey meat. Food Control, 40, 64–70.Han JH (2013) Innovations in food packaging.Hawkins, D. R., Rocabayera, X., Ruckman, S., Segret, R., & Shaw, D. (2009). Metabolism and pharmacokinetics of ethyl N-alpha-lauroyl-L-arginate hydrochloride in human volunteers. Food and Chemical Toxicology, 47(11), 2711–2715.Higueras, L., Lopez Carballo, G., Hernandez Munoz, P., Gavara, R., Rollini, M., López Carballo, G., & Hernández Muñoz, P. (2013). Development of a novel antimicrobial film based on chitosan with LAE (ethyl-N)-dodecanoyl-l-arginate) and its application to fresh chicken. International Journal of Food Microbiology, 165(3), 339–345.Kilcast D & Subramaniam P (2000) The stability and shelf-life of food. Woodhead Publishing CambridgeMuriel-Galet, V., Lopez-Carballo, G., Gavara, R., & Hernandez-Munoz, P. (2012). Antimicrobial food packaging film based on the release of LAE from EVOH. International Journal of Food Microbiology, 157(2), 239–244.Muriel-Galet, V., López-Carballo, G., Hernández-Muñoz, P., & Gavara, R. (2013). Characterization of ethylene-vinyl alcohol copolymer containing lauril arginate (LAE) as material for active antimicrobial food packaging. Food Packaging and Shelf Life, 1, 10–17.Rodriguez, E., Seguer, J., Rocabayera, X., & Manresa, A. (2004). Cellular effects of monohydrochloride of L-arginine, N-alpha-lauroyl ethylester (LAE) on exposure to Salmonella typhimurium and Staphylococcus aureus. Journal of Applied Microbiology, 96(5), 903–912.Sallam, & Ibrahim, K. (2007). Antimicrobial and antioxidant effects of sodium acetate, sodium lactate, and sodium citrate in refrigerated sliced salmon. Food Control, 18(5), 566–575.Sung, S.-Y., Sin, L. T., Tee, T.-T., Bee, S.-T., Rahmat, A. R., Rahman, W. A. W. A., Tan, A.-C., & Vikhraman, M. (2013). Antimicrobial agents for food packaging applications. Trends in Food Science & Technology, 33(2), 110–123.Theinsathid, P., Visessanguan, W., Kruenate, J., Kingcha, Y., & Keeratipibul, S. (2012). Antimicrobial activity of lauric arginate-coated polylactic acid films against Listeria monocytogenes and Salmonella typhimurium on cooked sliced ham. Journal of Food Science, 77(2), M142–149

Innovations and trends in the packaging of fruits and vegetables

[SPA] Los cambios físicos, químicos y microbiológicos que tienen lugar en las frutas y hortalizas tras su recolección llevan indefectiblemente a la pérdida de calidad y aceptabilidad durante su comercialización. Con la elección de la tecnología de conservación y envasado y del material de envase con las adecuadas características de barrera a gases y vapores, así como su respuesta a los diferentes factores externos como la temperatura, la humedad, la luz, y las manipulaciones propias de la comercialización se puede conseguir alargar la vida útil de los alimentos con garantías de calidad y seguridad. El envasado en atmósfera modificada es en la actualidad la tecnología de conservación más ampliamente utilizada para la comercialización de frutas y hortalizas en fresco. Con la adecuada composición de la atmósfera de envasado en combinación con la refrigeración se reduce el crecimiento de microorganismos, así como los procesos metabólicos y la pérdida de agua. Ahora bien, esta tecnología de envasado no es suficiente en muchas ocasiones para mantener adecuadamente el producto durante todo el periodo de comercialización y hasta su consumo. El envasado activo puede significar para estos productos una excelente alternativa, efectiva y económica para la conservación de estos productos. En esta ponencia se revisan las bases del envasado activo y se comentan algunas de las tecnologías de interés práctico y las perspectivas de futuro. [ENG] The physical, chemical and microbiological changes that take place in fruits and vegetables after harvesting lead unfailingly to the loss of quality and acceptability during their commercialization. It is possible to lengthen the shelf life of food maintaining its quality and security with an adequate election of preservation and packaging technologies and a package design with the appropriate barrier characteristics to gases and vapours, as well as its responses to the different external factors such as temperature, humidity, light, and manipulations during de distribution and marketing, Among the diverse packaging alternatives, modified atmosphere packaging is the most common preservation technology for fresh produce since it can help to decrease respiration rate and transpiration, retard or prevent microbial growth and reduce metabolic activity in minimally processed fruits and vegetables. Although this packaging technology in combination with refrigeration can delay deterioration of the fresh product, it is not always sufficient for the purpose of maintaining its quality for the desired marketing period. As an alternative, active packaging opens up an effective, economical way of increasing the shelf life of fresh produce during transport and marketing. This presentation reviews the present state and future perspectives of both modified atmosphere packaging and active packaging technologies for fruits and vegetables

Environmental assessment of antimicrobial coatings for packaged fresh milk

Antimicrobial coatings are being increasingly used as a means to extend the shelf life of food products. This extension helps consumers cut down on the food waste generated at household level, while at the same time reducing the impact, which these products' life cycle has on the environment. The aim of this Life Cycle Assessment study is thus to assess the consequences on the environment arising from the application of an antimicrobial coating onto the packaging of a fresh milk product, while also taking into account the reduction in milk waste. The antimicrobial coating considered is a synthetic derivative of lauric acid. The application of the coating involves additional environmental impacts caused by all the inputs and outputs which occur during its life cycle. At the same time, however, the use of this coating allows to extend the fresh milk's shelf life with a consequent reduction in food waste. The data related to the production and application of the coating were provided by the packaging laboratory of the Institute of Agrochemistry and Food Technology (Valencia) and by manufacturing companies. The data related to food waste, milk processing, refrigeration transports, storage, and end of life of both product and packaging were obtained from previous studies, institutional reports and Ecoinvent database v2.2. The Midpoint Impact 2002 method was used to assess impacts. The results show how the reduction in milk waste achievable by using the coating generates higher environmental benefits than the impacts caused by the coating's life cycle due to milk saving. Furthermore this study demonstrates the importance of including food waste in Life Cycle Assessment studies of packaging systems. The connection between packaging design and food waste is a decisive aspect in the evaluation of actual environmental sustainability and should thus be considered in all assessments of packaging solutions. (C) 2015 Elsevier Ltd. All rights reserved.Manfredi, M.; Fantin, V.; Vignali, G.; Gavara Clemente, R. (2015). Environmental assessment of antimicrobial coatings for packaged fresh milk. Journal of Cleaner Production. 95:291-300. doi:10.1016/j.jclepro.2015.02.0482913009

Immobilization of beta-cyclodextrin in ethylene-vinyl alcohol copolymer for active food packaging applications

[EN] Current developments in active food packaging are focusing on incorporating agents into the polymeric package walls that will release or retain substances to improve the quality, safety and shelf-life of the food. Because cyclodextrins are able to form inclusion complexes with various compounds, they are of potential interest as agents to retain or scavenge substances in active packaging applications. In this study, beta-cyclodextrin (beta CD) was successfully immobilized in an ethylene-vinyl alcohol copolymer with a 44% molar percentage of ethylene (EVOH44) by using regular extrusion with glycerol as an adjuvant. Films with 10%, 20% and 30% of beta CD were flexible and transparent. The presence of the agent slightly increased the glass-transition temperature and the crystallinity percentage of the polymer, that is to say, it induced some fragility and a nucleating effect. The water vapor, oxygen and carbon dioxide barrier properties of the materials containing beta CD were determined and compared with those of the pure polymeric material. Permeability to these three permeants increased with the addition of beta CD due to the presence of discontinuities in the matrix and to the internal cavity of the oligosaccharide. Also the CO2/O-2 permselectivity increased with the addition of beta CD. Finally, the potential effect of the composites in the food aroma was analyzed. The materials with beta CD preferentially sorbed apolar compounds such as terpenes. This characteristic could be useful in active packaging applications for preferentially retaining undesired apolar food components like hexanal or cholesterol. (C) 2010 Elsevier B.V. All rights reserved.The authors acknowledge the financial support of the Spanish Ministry of Science and Innovation, projects AGL2006-02176 and Fun-C-Food CSD2007-00063, and the C. L-d-D fellowship (FPU program). Mary Georgina Hardinge provided assistance with the English language text.Lopez-De-Dicastillo, C.; Gallur, M.; Catala Moragrega, R.; Gavara Clemente, R.; Hernandez-Muñoz, P. (2010). Immobilization of beta-cyclodextrin in ethylene-vinyl alcohol copolymer for active food packaging applications. Journal of Membrane Science. 353(1-2):184-191. https://doi.org/10.1016/j.memsci.2010.02.049S1841913531-

Improving the Antioxidant Protection of Packaged Food by Incorporating Natural Flavonoids into Ethylene-Vinyl Alcohol Copolymer (EVOH) Films

This document is the unedited Author s version of a Submitted Work that was subsequently accepted for publication in Journal of Agricultural and Food Chemistry, copyright © American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/jf1022324[EN] Ethylene-vinyl alcohol copolymer (EVOH) films containing catechin or quercetin as antioxidant agents were successfully produced by extrusion. The addition of these bioactive compounds did not modify greatly their water and oxygen permeabilities, T-g, or crystallinity but improved their thermal resistance. Exposure of the films to different food simulants showed that both compounds were released, although the extent and kinetics of release were dependent on the type of food. In aqueous and alcoholic food simulants their release was greater in the case of the catechin-containing samples. Exposure of the films to isooctane and ethanol 95% (fatty food simulants) provided controversial results; no release was observed in isooctane, whereas both bioactive compounds were extracted by ethanol due to their high solubility in alcohol and the plasticizing effect of ethanol on the polymer. Packaging applications of these films can improve food stability and provide a method for adding such bioactive compounds.Received for review June 10, 2010. Revised manuscript received August 24, 2010. Accepted September 16, 2010. We acknowledge the financial support of the Spanish Ministry of Science and Innovation, Projects AGL2006-02176, AGL2009-08776, and Fun-C-Food CSD2007-00063, and the C.L.-d.-D. fellowship (FPU program).Lopez-De-Dicastillo, C.; Alonso, JM.; Catala Moragrega, R.; Gavara Clemente, R.; Hernandez-Muñoz, P. (2010). Improving the Antioxidant Protection of Packaged Food by Incorporating Natural Flavonoids into Ethylene-Vinyl Alcohol Copolymer (EVOH) Films. Journal of Agricultural and Food Chemistry. 58(20):10958-10964. https://doi.org/10.1021/jf1022324S1095810964582

Exploiting the Redox Activity of MIL-100(Fe) Carrier Enables Prolonged Carvacrol Antimicrobial Activity

The design of efficient food contact materials that maintain optimal levels of food safety is of paramount relevance to reduce the increasing number of foodborne illnesses. In this work, we develop a smart composite metal-organic framework (MOF)-based material that fosters a unique prolonged antibacterial activity. The composite is obtained by entrapping a natural food preserving molecule, carvacrol, into a mesoporous MIL-100(Fe) material following a direct and biocompatible impregnation method, and obtaining particularly high payloads. By exploiting the intrinsic redox nature of the MIL-100(Fe) material, it is possible to achieve a prolonged activity against Escherichia coli and Listeria innocua due to a triggered two-step carvacrol release from films containing the carvacrol@MOF composite. Essentially, it was discovered that based on the underlying chemical interaction between MIL-100(Fe) and carvacrol, it is possible to undergo a reversible charge-transfer process between the metallic MOF counterpart and carvacrol upon certain chemical stimuli. During this process, the preferred carvacrol binding site was monitored by infrared, Mössbauer, and electron paramagnetic resonance spectroscopies, and the results are supported by theoretical calculations

Anchoring gated mesoporous silica particles to ethylene vinyl alcohol films for smart packaging applications

[EN] This work is a proof of concept for the design of active packaging materials based on the anchorage of gated mesoporous silica particles with a pH triggering mechanism to a packaging film surface. Mesoporous silica micro- and nanoparticles were loaded with rhodamine B and functionalized with N-(3-trimethoxysilylpropyl)diethylenetriamine. This simple system allows regulation of cargo delivery as a function of the pH of the environment. In parallel, poly(ethylene-co-vinyl alcohol) films, EVOH 32 and EVOH 44, were ultraviolet (UV) irradiated to convert hydroxyl moieties of the polymer chains into -COOH functional groups. The highest COOH surface concentration was obtained for EVOH 32 after 15 min of UV irradiation. Anchoring of the gated mesoporous particles to the films was carried out successfully at pH 3 and pH 5. Mesoporous particles were distributed homogeneously throughout the film surface and in greater concentration for the EVOH 32 films. Films with the anchored particles were exposed to two liquid media simulating acidic food and neutral food. The films released the cargo at neutral pH but kept the dye locked at acidic pH. The best results were obtained for EVOH 32 irradiated for 15 min, treated for particle attachment at pH 3, and with mesoporous silica nanoparticles. This opens the possibility of designing active materials loaded with antimicrobials, antioxidants, or aromatic compounds, which are released when the pH of the product approaches neutrality, as occurs, for instance, with the release of biogenic amines from fresh food products.This research was funded by the Ministry of Economy, Industry, and Competitiveness, projects AGL2015-64595-R, AGL2015-70235-C2-1-R, and AGL2015-70235-C2-2-R.Muriel-Galet, V.; Pérez-Esteve, É.; Ruiz Rico, M.; Martínez-Máñez, R.; Barat Baviera, JM.; Hernandez-Muñoz, P.; Gavara Clemente, R. (2018). Anchoring gated mesoporous silica particles to ethylene vinyl alcohol films for smart packaging applications. Nanomaterials. 8(10). https://doi.org/10.3390/nano8100865S81

Base-Controlled Heck, Suzuki, and Sonogashira Reactions Catalyzed by Ligand-Free Platinum or Palladium Single Atom and Sub-Nanometer Clusters

[EN] The assumption that oxidative addition is the key step during the cross-coupling reaction of aryl halides has led to the development of a plethora of increasingly complex metal catalysts, thereby obviating in many cases the exact influence of the base, which is a simple, inexpensive, and necessary reagent for this paramount transformation. Here, a combined experimental and computational study shows that the oxidative addition is not the single kinetically relevant step in different cross-coupling reactions catalyzed by sub-nanometer Pt or Pd species, since the reactivity control is shifted toward subtle changes in the base. The exposed metal atoms in the cluster cooperate to enable an extremely easy oxidative addition of the aryl halide, even chlorides, and allow the base to bifurcate the coupling. With sub-nanometer Pd species, amines drive to the Heck reaction, carbonate drives to the Sonogahira reaction, and phosphate drives to the Suzuki reaction, while for Pt clusters and single atoms, good conversion is only achieved using acetate as a base. This base-controlled orthogonal reactivity with ligand-free catalysts opens new avenues in the design of cross-coupling reactions in organic synthesis.This work was supported by the MINECO (Spain) (projects CTQ2017-86735-P and Excellence Unit "Severo Ochoa" SEV-2016-0683). E.F.V. and M.M. thank MINECO for their fellowship SVP-2013-068146 and a predoctoral contract. We thank Jose M. Coll-Marques for performing the micro fluorescence measure-ments. Red Espanola de Supercomputacion (RES) and Centre de Cacul de la Universitat de Valencia are gratefully acknowledged for computational resources.Fernández, E.; Rivero-Crespo, MÁ.; Domínguez, I.; Rubio-Marqués, P.; Oliver-Meseguer, J.; Liu, L.; Cabrero-Antonino, M.... (2019). Base-Controlled Heck, Suzuki, and Sonogashira Reactions Catalyzed by Ligand-Free Platinum or Palladium Single Atom and Sub-Nanometer Clusters. Journal of the American Chemical Society. 141(5):1928-1940. https://doi.org/10.1021/jacs.8b0788419281940141