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Antimicrobial food grade hydroxybenzaldehyde derivatives were immobilized on the surface of chitosan films by means of reversible Schiff bases. Spectroscopy and elemental analysis evidenced the different ability of the aldehydes to form Schiff bases with chitosan. Chitosan films modified with Schiff bases of aldehydes exerted antimicrobial properties against E. coli under mild acidic environments. The efficacy of the films lied on the reversibility of synthetized imine bonds and release of the aldehydes which was promoted in mildly acid aqueous solutions. Besides acidity, imine bond reversibility depended on the chemical structure of the aldehyde covalently bonded. Films carrying salicylaldehyde presented the highest in vitro antimicrobial performance and thus, they were chosen to evaluate their effectivity in inhibiting E. coli proliferation in freshly-squeezed carrot-orange juice. Films were successfully activated by the acid environment of the juice and reduced the population of the inoculated pathogen. Salicylaldehyde migrated to the juice did not exert toxic effects on Caco-2 cells., The authors acknowledge the financial support of the Spanish Ministry of Science and Innovation (Grants RTI2018-093452-B-I00, MAT2017-83014-C2-2P and BES-2016-077380 funded by MCIN/AEI/ 10.13039/501100011033 and by ERDF A way of making Europe). PHM, RH and RG are members of the Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy (SusPlast) from the Spanish National Research Council (CSIC) (CSIC program for the Spanish Recovery, Transformation and Resilience Plan funded by the Recovery and Resilience Facility of the European Union, established by the Regulation (EU) 2020/2094).

© 2021 by the authors., The inhibitory and bactericidal capacity of Listex P100 bacteriophage has been studied against different concentrations of Listeria monocytogenes in stationary and exponential phases. Three different matrices were employed to developed films incorporating Listex P100: (1) sodium caseinate, (2) sodium alginate mixed with gelatin, and (3) polyvinyl alcohol (PVOH). All the films were successfully developed by casting at room temperature. These active biodegradable films were optical, structural, and thermally characterized, and their antimicrobial capacities against L. monocytogenes were studied. The incorporation of phages did not affect the morphology, colour, opacity, and thermal stability of polymers. The antimicrobial analysis revealed the bacteriophage presented a high antimicrobial capacity against L. monocytogenes in the stationary phase (4.40 and 6.19 log reduction values or bactericide effect depending on the initial inoculum of the pathogen). Developed films showed antimicrobial capacity close to 1 log after 24 h of incubation at 30 °C. The effectiveness of PVOH films was greater under refrigeration conditions, reaching 2 log reduction after eight days of incubation. The use of these films as a coating in a food or as part of a packaging could improve food safety against the growth of pathogenic microorganisms such as Listeria monocytogenes., The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness (AGL2015-64595-R) and the financial support of CONICYT through the Project Fondecyt Regular 1200766 and “Programa de Financiamiento Basal para Centros Científicos y Tecnológicos de Excelencia” Project FB0807.

The aim of the present work was the development of antimicrobial films containing garlic extract to be applied as active packaging for preservative-free sliced pan loaf, with the goal of extending its shelf-life. First, the antimicrobial capacity of garlic extract, a compound used as active agent, was tested against Penicillium expansum by the disc diffusion method. The extract showed high antimicrobial activity, 0.1 μL per Petri dish being the minimum inhibitory amount, and 0.25 μL the minimum fungicidal amount. Bread aroma was also used to mask the pungent odour of garlic and it was confirmed to have no antimicrobial activity. Subsequently, polyethylene (PE) aqueous emulsion and ethylene-vinyl alcohol copolymer (EVOH) and zein hydroalcoholic solutions containing 0.25 and 0.5% (w/w per dry polymer) of garlic extract and bread aroma were used to coat PE films, producing PE/PE, PE/EVOH and PE/zein active films. The antimicrobial capacity of the films was studied in vitro against Penicillium expansum, and in vivo with natural sliced bread. The results showed that all the films presented some antimicrobial activity, PE film coated with zein containing 0.5% of garlic extract and bread aroma being the film presenting the best results, maintaining bread free of mould infection for 30 days. Sensory tests showed that the addition of 1% of bread aroma improved the sensory experience of consumers and also revealed good purchase intention., The authors acknowledge the financial support of the Spanish Ministry of Economy and Innovation, project AGL2015-64595-R, and Juan y Juan S.L., and R. H.-M.'s fellowship

The incorporation of lactic acid bacteria (LAB) in edible films and coatings has recently emerged as an innovative strategy to provide packaging films with new functionalities in order to ensure food quality and safety. In this work, bioactive films were made by incorporating Lactococcus lactis subsp. lactis in cast polyvinyl alcohol (PVOH) matrices, alone or blended with a small percentage of proteins, protein hydrolysates, or yeast extract, and the effect of incorporating them on the morphology and optical properties of the PVOH films was studied. Moreover, the viability of L. lactis in the films developed stored at 20 °C and 43.2% relative humidity for four weeks, and the antimicrobial activity against L. monocytogenes were determined. The thickness, color properties, and morphology of the films incorporating LAB and nutrients did not show significant differences compared with plain PVOH films, but moisture content increased slightly with nutrient incorporation. L. lactis remained viable for 4 weeks of storage, but viability depended on the matrix composition, being lower in plain PVOH films and higher in films supplemented with proteins, hydrolysates, or yeast extract. The highest antimicrobial activity was observed in PVOH matrices with hydrolyzed gelatin or casein, and the lowest in plain PVOH films. The growth of L. lactis was similar in all the films after incubation in contact with L. monocytogenes at 37 °C in liquid medium, regardless of the initial concentration. The films developed could be applied in the design of food packages with the purpose of inhibiting growth of L. monocytogenes.

The aim of this work has been to explore the potential of blending polyvinyl alcohol (PVOH) with casein hydrolysates (HCas) to obtain self-standing films capable to act as carriers of lactic acid bacteria (LAB) as biocontrol agents against food pathogens. For this purpose, PVOH was blended with HCas at different weight ratios and the blends were incorporated with Lactococcus lactis and Lactobacillus sakei. Blending HCas with PVOH resulted in the modification of some functional properties of the films whereas bacteria did not change them. Moreover, incorporation of HCas resulted in an increase in cell viability after film casting and in long-term film storage, and also in film antilisterial properties. These results could be related to the capacity of bacterial autoaggregation in the films during the drying process when HCas was added, as observed by fluorescence light microscopy. Blends could be used in the active packaging of foods., The authors acknowledge the financial support of the Spanish Ministry of Science, Innovation and Universities (AGL2015-64595-R, RTI2018-093452-B-I00).

Zein films loaded with 5 or 10% of Zataria multiflora Boiss. essential oil (ZEO) were successfully obtained. Migration of antimicrobial carvacrol and thymol, major components of ZEO, was monitored at different temperatures and with different food simulants, and apparent diffusion was calculated. Antimicrobial properties of the films were assayed in vapour phase and liquid medium. The results showed that films containing 5% ZEO achieved reductions of 1.18 log and 1.14 log against L. monocytogenes and E. coli , respectively, and the log reduction value increased to 2.16 log and 2.65 log for films with 10% ZEO. However, the films lacked antimicrobial activity when tested in vapour phase. Finally, thin zein films loaded with 10% ZEO were successfully applied as a coating on PP bags. The effectiveness of the active bags was tested in a more complex medium than liquid bacterial growth media, that is cow's milk inoculated with the above microorganisms. This work offers a successful approach on the use of zein proteins for active food packaging.

Curcumin is a polyphenol with a wide range of biological properties, including antioxidant and antimicrobial activity; however, its use as a food preservative is limited because of its insolubility in water. The present work is an attempt to overcome this problem by means of matrix encapsulation of curcumin in gelatin through electrohydrodynamic atomization (EHDA). Compact spherical gelatin particles ranging from few nanometers to more than 1 μm in diameter loaded with 10% (w/w) curcumin were successfully obtained, and the encapsulation efficiency being close to 100%. Fluorescence microscopy indicated that the curcumin was homogeneously distributed in the particles, while modulated differential scanning calorimetry analysis showed that the curcumin was intimately mixed with gelatin polymer, and a complete loss of curcumin crystallinity was observed in the solid dispersion. Furthermore, the UV–visible spectrum of dissolved/dispersed particles showed a shift of the maximum absorbance of curcumin toward lower wavelengths, indicating gelatin–curcumin interactions. The water solubility of curcumin increased 38.6-fold after it had been encapsulated in gelatin microparticles. With regard to antioxidant properties, they increased when blended with gelatin compared with commercial curcumin powder. Although antibacterial activity of raw curcumin was negligible at concentrations up to 100 mg/ml, gelatin-encapsulated curcumin at 4 mg/ml reduced the microbial population by 2.08, 1.67, 2.70, and 2.18 log counts (CFU/ml) for L. monocytogenes, S. enterica, S. aureus, and E. coli, respectively. Accordingly, it was proved that encapsulation of curcumin in gelatin particles by EHDA greatly improved its antioxidant and antimicrobial properties, thus broadening its potential use as a food preservative.

The aim of this work was to develop active edible coatings based on marine polysaccharide matrices and polyphenols-enriched native plant extracts from arid and semiarid regions of Argentina. Initially, five plant extracts were characterized in terms of antioxidant, antibacterial and antiviral activity and the one with better biological properties and no toxicity or genotoxicity, Larrea nitida (Ln) extract, was incorporated into agar, alginate or agar/alginate matrices. The Ln extract-containing films were characterized in terms of physicochemical and polyphenols release performance in food simulants. The incorporation of Ln extract provided darker films, with a more saturated orange-brownish color and with negligible effects on mechanical and barrier properties. Additionally, all the coatings showed antiviral activity when applied to blueberries against murine norovirus (MNV), a cultivable norovirus surrogate. The coatings of agar and Ln extract was able to reduce the infectivity of MNV below the limit of detection after over-night (ON) incubation at 25 °C and after 4 days at 10 °C storage. These edible polysaccharides coatings containing Ln extract could be an alternative to reduce or eliminate foodborne viruses and protect the food against oxidative process., This research was supported by grants from Secretaría de Ciencia, Arte e Innovación Tecnológica de la Universidad Nacional de Tucumán, Argentina (PIUNT 637), Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina (Proyecto UE-0011, doctoral and postdoctoral scholarship), Agencia Nacional de Promoción Científica y Tecnológica (PICT 3136, PICT 4436), Agencia Estatal de Investigación (AEI, Grant PCI2018-092886) and cofunded by the European Union's Horizon 2020 research and innovation programme (ERA-Net SUSFOOD2), and EMHE-CSIC (Grant MHE-200038). MJF was supported by a Ramon y Cajal contract (RYC2014-158) from the Spanish Ministerio de Economia; Industria y Competitividad. The authors thank the Central Support Service for Experimental Research (SCSIE) of the University of Valencia for the electronic microscopy service.

In this study, zein coatings containing Lauroyl-l-arginine ethyl ester monohydrochloride (LAE) were developed to be applied on polypropylene films and manufacture an active food packaging. The concentration of LAE and the addition of a suitable plasticizer (glycerol or oleic acid (OA)) were the main variables considered. Active plasticized zein films, with glycerol or oleic acid were characterized in terms of release kinetics, mechanical, barrier, optical, and antimicrobial properties. Results showed that active agent concentration, (5 and 10%), had no-significant effect on mechanical and WVP properties of the plasticized films. Films plasticized with OA presented greater water resistance, UV-light opacity, and water barrier properties than glycerol-plasticized films. On the contrary, the latter had better antimicrobial properties. The analysis of LAE release kinetics from films to different food simulants revealed different behaviours, depending on both film formulation and food simulant. Despite the lower water resistance of coatings containing glycerol, bags based on polypropylene/glycerol plasticized zein containing 10% of LAE presented a great antimicrobial activity in tests with chicken soup (real food system) contaminated with pathogen bacteria, concretely, the films showed 3.21 Log reduction against Listeria monocytogenes and 3.07 log reductions against Escherichia coli. These results suggest a promising strategy on the use of LAE-containing zein in active food packaging to control foodborne pathogens., Financial support of the Ministry of Science, Innovation and Universities; project AGL AGL2015-64595-R.

An innovative edible coating, made from food grade polyvinyl alcohol (PVOH) and gelatin hydrolysates (HGel), was evaluated as a carrier of Lactococcus lactis acting as anti-listeria protective culture for refrigerated foods. The coating was applied on a compostable polylactic acid film surface and its anti-listeria activity was evaluated at 4 °C in a liquid culture medium and in solid agar, inoculated with Listeria monocytogenes. The best results were obtained in agar, exerting a bactericide effect, whereas in the liquid medium the coating had bacteriostatic behaviour. Furthermore, the active coating was applied to the surface of bags or separator liners made from polylactic acid. Its effectivity was evaluated with creamy mushroom soup (bags) and sliced cooked ham (separator liners) previously inoculated with L. monocytogenes and stored at 4 °C. Results showed that the coating was effective at inhibiting pathogen growth; however, it did not display a bactericide effect in the foods. In addition, L. lactis remained viable in all experiments conducted in this study. The acidification produced by L. lactis, because of the generation of organic acids, did not compromise the sensory properties of the sliced cooked ham after 16 days of refrigerated storage. In contrast, consumers perceived a mushroom soup acidification because of a greater decrease in pH than the sliced cooked ham. This study demonstrates that a food grade polyvinyl alcohol polymer blended with gelatin hydrolysates can be used as a carrier of protective cultures of L. lactis to increase the microbiological safety of refrigerated foods.

Cast films obtained from polyvinyl alcohol (PVOH) blended with casein hydrolysates (HCas) in a weight ratio of 1:1 were employed to carry nisin-producing L. lactis and phytic acid in order to broaden the antimicrobial spectrum of L. lactis to Gram-positive and Gram-negative spoilage and pathogen bacteria. For this purpose, the effect of the antimicrobial activity of various film formulations and combinations of films on the growth of E. coli at 37 °C for 24 h was studied. The film system that showed antimicrobial activity against Gram-negative bacteria consisted of phytic acid and L. lactis incorporated in separate films. When the active agents were in the same film the viability of L. lactis decreased considerably and it did not exert antimicrobial activity against the bacterium. Therefore, the combination of L. lactis and phytic acid in separate films was chosen as the reliable system, and the effect of its activity on the growth of Gram-negative bacteria (E. coli, Salmonella enterica, and Pseudomonas fluorescens) and Gram-positive bacteria (Listeria monocytogenes) in liquid culture medium was tested at refrigeration temperature (4 °C), and with simulated breaks in the cold chain (14 °C and 24 °C). The survival of L. lactis in coexistence with these bacteria was also studied. The film system exerted an antimicrobial effect against the Gram-negative bacteria tested, and the activity depended on the bacteria and the temperature assayed. With regard to the antimicrobial activity against L. monocytogenes, phytic acid improved the antimicrobial capacity of L. lactis. The survival of L. lactis was maintained at 7–8 log (CFU/mL) culture in liquid medium throughout the storage period. The films developed were intended to be used as coatings in the design of a double-sided active bag for a non-fermented dairy product. The bags were filled with homemade preservative-free pastry cream, and the microbiological shelf life and evolution of pH of the packaged ready-to-eat food stored at 4 °C was studied for 20 days. The results showed a reduction in the growth of spoilage bacteria and therefore an increase in the shelf life of the packaged product. The films developed could be applied in the design of packages for perishable dairy foods in order to increase their microbiological shelf life.

PVOH-based polymer matrices in the form of films were evaluated as carriers of living Lactococcus lactis subsp. Lactis. These lactic acid bacteria are capable of producing nisin, which is an effective antilisterial peptide. A low percentage (1:0.125 w/w) of yeast extract, gelatin, sodium caseinate, gelatin, or casein hydrolysates was incorporated in PVOH matrices with the aim of increasing the viability of bacteria in the film. The films were obtained by casting after incorporating L. lactis. Then they were evaluated for antilisterial activity in liquid medium at 37 °C for 24 h, and also at 4 °C for 21 days in order to simulate the storage of liquid foods in refrigeration conditions. The survival of the lactic acid bacteria was also evaluated at both temperatures during the experiment. L. lactis remained viable in all the films tested at 37 and 4 °C. The antimicrobial activity of the films was greater at 4 °C than at 37 °C. With regard to the effect of the film composition, the activity of the films was higher when protein hydrolysates and sodium caseinate were incorporated in the formulation. Films supplemented with protein hydrolysates or sodium caseinate inhibited growth of the pathogen during the 21 days of storage at 4 °C. At 37 °C, after 24 h the films had slowed the growth of the inoculated pathogen by between 2 and 4 log CFU/mL. Finally, as the films developed are intended to be used in the design of active packaging of foods, they were tested in pasteurized milk inoculated with 4 log CFU/mL of Listeria monocytogenes and stored at 4 °C for 21 days. The pathogen began to grow after the second day of storage with or without film, but when the films were added to the medium the growth of the pathogen was slowed down, without reaching >6 log CFU, whereas the control reached a maximum growth of 8.5 log CFU. The pH of the milk was monitored throughout the experiment, and it decreased with time. This was due to the generation of organic acids by the lactic bacteria. Buffering the food stabilized the pH without modifying the activity of the films. Thus, the current study shows that PVOH films supplemented with nutrients can act as carriers of L. lactis, and they can help to increase the safety of refrigerated dairy beverages and sauces.

A chromatic sensor has been designed for the detection of oxygen in package headspace. The sensor is based on the redox change of methylene blue (MB) to its leuco form. Its formulation includes the pigment, glycerol, as a sacrificial electron donor, TiO, as a photocatalyst and ethylenevinyl alcohol copolymer (EVOH), as a structural polymer matrix. The final sensor design that allows its manufacture by conventional printing and laminating technologies consists of the sensing polymer matrix (MB-EVOH) sandwiched in a suitable transparent multilayer structure. The outer layers protect the sensor from the external atmosphere and allow visualization of the colour. The inner layer is sufficiently opaque to facilitate sensor reading from the outside, is thick enough to avoid direct contact with food (functional barrier), and is oxygen-permeable to expose the sensing material to the internal package atmosphere. In the absence of oxygen, the sensor becomes white by irradiation with halogen lamps in less than 60 s. All components are substances permitted for food contact except the pigment, but specific migration analysis showed no trace of migration thanks to the functional barrier included in the design., This research was funded by Spanish Ministry of Economy and Innovation, project AGL2015-64595-R and Juan y Juan S.L.

This chapter revises how nanotechnology can contribute to improve quality and safety of packaged foods. In this regard, the use of nanosized materials for the formation of polymer nanocomposites for different purposes is exposed. Next, main applications of polymer nanocomposites are described in detail: enhancement of physical properties of packaging films such as barrier and mechanical properties through the use of nanofillers; the application of metallic nanoparticles with antimicrobial or antioxidant properties embedded in polymeric films for the development of active packages is contemplated; and the latest advances in sensors based in nanoparticles for smart packaging are described. The risks for human heath, and the environmental impact of nanotechnology applied to food packaging is also addressed in this chapter. Finally, legal issues regarding nanomaterials for food contact applications are contemplated.

Chlorophyllins are semi-synthetic porphyrins obtained from chlorophyll that&mdash, when exposed to visible light&mdash, generate radical oxygen substances with antimicrobial activity. In this work, chlorophyllins incorporated with polyethylene (PE), polyvinyl alcohol (PVOH), (hydroxypropyl)methyl cellulose (HPMC), and gelatin (G) were formulated for application as coatings in packages providing antimicrobial activity after photoactivation. First, the antimicrobial properties of two porphyrins (sodium magnesium chlorophyllin, E-140, and sodium copper chlorophyllin, E-141) were analyzed against L. monocytogenes and Escherichia coli. The results indicated that E-140 was more active than E-141 and that chlorophyllins were more effective against Gram-positive bacteria. In addition, both chlorophyllins were more efficient when irradiated with halogen lamps than with LEDs, and they were inactive in dark conditions. Then, coatings on polyethylene terephthalate (PET) film were prepared, and their effect against the test bacteria was similar to that shown previously with pure chlorophyllins, i.e., greater activity in films containing E-140. Among the coating matrices, those based on PE presented the least effect (1 log reduction), whereas PVOH, HPMC, and G were lethal (7 log reduction). The self-sanitizing effect of these coatings was also analyzed by contaminating the surface of the coatings and irradiating them through the PET surface, which showed high efficiency, although the activity of the coatings was limited to L. monocytogenes. Finally, coated films were applied as separators of bologna slices. After irradiation, all the films showed count reductions of L. monocytogenes and the usual microbial load, the gelatin coating was the most effective, with an average of 3 log reduction.

The aim of this work was the industrial development of an antifungal film containing garlic extract and bread aroma to be applied as active packaging for preservative-free sliced pan loaf. The material consisted of LDPE coated with ethylene vinyl alcohol copolymer. First the coating formulation was optimized to be suitable for flexographic equipment. A 1 μm coating of EVOH containing the agents was applied onto the LDPE film. Garlic extract release provides the antimicrobial capacity while bread aroma masks the inappropriate garlic aroma. The optimized formulation contained 8% of garlic extract and 8% of bread aroma. Bags were prepared and used to pack sliced pan loaves. Mould development was delayed from 6 to 12 days by use of the active bag. Sensory and textural characterization of the food also revealed that the bread maintained its characteristics, and sensory panellists considered the product acceptable and with good purchase intention., The authors acknowledge the financial support of the Spanish Ministry of Economy and Innovation, project AGL2015-64595-R and R. H.-M.’s fellowship, and Juan y Juan S.L.

The knowledge of the biological properties of fruits and leaves of murta (Ugni molinae Turcz.) has been owned by native Chilean culture. The present study investigated the phenolic content, the antioxidant, antimicrobial and anti-tyrosinase activities of different murta fruit and leaves extracts to approach their uses on future food, pharmaceutical and cosmetic applications. Extractions of murta fruit and leaves were carried out under water, ethanol and ethanol 50%. Phenolic content of these extracts was measured through Folin Ciocalteu test and the antioxidant power by four different antioxidant systems (ORAC, FRAP, DPPH and TEAC assays) owing to elucidate the main mechanism of antioxidant. Some flavonoids, such as rutin, isoquercitrin and quercitrin hydrate were identified and quantified through HPLC analysis. Antimicrobial activity was determined measuring minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) values against Escherichia coli and Listeria monocytogenes, and the effect of these extracts on L. monocytogenes was confirmed by flow cytometry. Highest contents of polyphenol compounds were obtained in hydroalcoholic extracts (28±1mggallicacid/g dry fruit, and 128±6mggallicacid/g dry leaves). The same trend was found for the values of biological properties: hydroalcoholic extracts showed the strongest activities. Leaves presented higher antioxidant, antimicrobial and anti-tyrosinase properties than murta fruit. Highest antioxidant activity values according to ORAC, FRAP, TEAC and DPPH were 80±8mgTrolox/g, 70±2mgTrolox/g, 87±8mgTrolox/g and 110±12mgTrolox/g, respectively, for murta fruit samples, and 280±10mgTrolox/g, 192±4mgTrolox/g, 286±13mgTrolox/g and 361±13mgTrolox/g, respectively, for murta leaves. These activities were confirmed by HPLC analysis that revealed highest presence of analyzed compounds on leaves hydroalcoholic extract. Regarding to antimicrobial analysis, hydroalcoholic leaves extract presented the highest activity presenting the lowest MIC value for L. monocytogenes (0.07mg/mL). This extract also performed the highest anti-tyrosinase activity (CE50 values of 1.6±0.3 (g/L) and 8.9±1.2 (g/L) for leaves and fruit, respectively).

[EN] Chitosan/cyclodextrin films (CS:CD) incorporating carvacrol were obtained by casting, and conditioned at 23 degrees C and 75% relative humidity prior to being immersed in liquid carvacrol until they reached sorption equilibrium. In a previous work, the in vitro antimicrobial activity of these films was studied. In this work, active films were used to inhibit microbial growth in packaged chicken breast fillets. Samples of CS:CD films loaded with carvacrol, of different sizes and thus with different quantities of antimicrobial agent, were stuck to the aluminium lid used to seal PP/EVOH/PP cups containing 25 g of chicken fillets. These samples were stored for 9 days at 4 degrees C. The packages were hermetically sealed and it was confirmed that they provided an infinite barrier to carvacrol. The partition of the antimicrobial agent within the food/packaging system was analysed. The antimicrobial devices rapidly released a large percentage of the agent load, amounts that were gained by the adhesive coating of the lid and especially by the chicken fillets. The latter were the main sorbent phase, with average concentrations ranging between 200 and 5000 mg/Kg during the period of storage. The microbiota of the packaged fresh chicken fillets - mesophiles, psychrophiles, Pseudomonas spp., enterobacteria, lactic acid bacteria and yeasts and fungi were analysed and monitored during storage. A general microbial inhibition was observed, increasing with the size of the active device. Inhibition with a 24 cm(2) device ranged from 0.3 log reductions against lactic acid bacteria to 1.8 logs against yeasts and fungi. However, the large amount of antimicrobial that was sorbed or that reacted with the fillet caused an unacceptable sensory deterioration. These high sorption values are probably due to a great chemical compatibility between chicken proteins and carvacrol. (C) 2014 Elsevier B.V. All rights reserved., The authors are grateful for financial support from the Spanish Ministry of Science and Innovation (project AGL2012-39920-C03-01), EU (Nafispack project 212544) and CSIC/European Social Fund (JAE-Predoc, L.H. fellowship), and to Mr. Karel Clapshaw (translation services).

[EN] Gliadin films incorporating 1.5, 3 and 5% cinnamaldehyde (g/100 g protein) were tested against food-spoilage fungi Penicillium expansum and Aspergillus niger in vitro, and were employed in an active food packaging system for sliced bread and cheese spread. Gliadin films incorporating cinnamaldehyde were highly effective against fungal growth. P. expansum and A. niger were completely inhibited after storage in vitro for 10 days in the presence of films incorporating 3% cinnamaldehyde. Indeed 1.5% cinnamaldehyde was sufficient in the case of P. expansum. The amount of cinnamaldehyde retained in films after storage for 45 days at 20 degrees C and 0% RH was also sufficient in most cases to prevent fungal growth in vitro. Active food packaging with gliadin films incorporating 5% cinnamaldehyde increased the shelf-life of both sliced bread and cheese spread. Mold growth was observed on sliced bread after 27 days of storage at 23 degrees C with active packaging, whereas in the control bread packaged without the active film fungal growth appeared around the fourth day. In the cheese spread, no fungi were observed after 26 days of storage at 4 degrees C when the product was packaged with the active film. However, growth of fungi was observed in control packaged cheese after 16 days of storage. This work demonstrates a noteworthy potential of these novel bioplastics incorporating natural antimicrobial compounds as innovative solutions to be used in active food packaging to extend shelf-life of food products. (C) 2013 Elsevier B.V. All rights reserved., The authors would like to thank the Spanish Ministry of Science and Innovation for financial support (project AGL2009-08776 and M.P. Balaguer's FPI fellowship). The authors wish to thank Dr. Andrew MacCabe for critical reading of the paper, and Joan Villanova for his assistance.

[EN] The aim of this study was to improve the present packaging of salad by combining modified atmosphere packaging with a new antimicrobial active bag consisting of PP/EVOH film with oregano essential oil or citral, with the purpose of extending shelf-life and reducing possible microbiological risks. The (O-2) and CO2 barrier properties of PP/EVOH, mechanical properties (Young's modulus, tensile strength and elongation at break) were determined and compared with those of standard PP films. Antimicrobial tests were carried out for enterobacteria, total aerobic counts, yeasts and moulds, and lactic acid bacteria and psychrotrophic bacteria, and the effect of the release of the antimicrobial agent on the sensory characteristics of the salads was also studied. The application of the EVOH coating results in an increase in the tensile resistance of the PP films and a reduction in the elongation at break. The results showed that microorganism counts bacteria decreased especially at the beginning of the storage period. OEO and CITRAL samples had reductions of 1.38 log and 2.13 log respectively against enterobacterias, about 2 log against yeasts and moulds. The total aerobic counts reduced 1.08 log with OEO and 1.23 log with CITRAL and the reduction of lactic acid bacteria and psychrotrophic was about 2 log. Citral-based films appeared to be more effective than materials containing oregano essential oil in reducing spoilage flora during storage time. Sensory studies also showed that the package with citral was the most accepted by customers at the end of the shelf-life. (C) 2012 Elsevier Ltd. All rights reserved, Authors thank the financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2009-08776 and V.M-G fellowships), EU (Nafispack project 212544), Generalitat Valenciana (J.P.C. fellowship) and Mr. Karel Clapshaw (translation services).

Ethylene-vinyl alcohol copolymers (EVOH) are a family of thermoplastic polymers with application in many industrial sectors including packaging and, especially, food packaging. The main characteristic of EVOH copolymers for packaging applications is their outstanding barrier to gases (oxygen, carbon dioxide, …) and organic vapors (food aroma). EVOH is applied in multilayer structures for bags, trays, cups, bottles, squeezable tubes or jars to protect oxygen-sensitive products. However, the hydrophilic nature of EVOH must be taken in consideration in package design to minimize water uptake and polymer swelling during thermal treatment processes such as retorting. This article reviews EVOH applications in barrier packaging and in active packaging.

Novel antimicrobial biopolymer films based on the incorporation of ethyl-Nα-dodecanoyl-l-arginate hydrochloride (LAE) in zein matrices were manufactured and characterized as materials for LAE controlled released applications such as active food packaging. Characterization of the films’ functional properties revealed that incorporation of LAE (5 and 10%) in the biopolymer matrix did not cause substantial changes in morphological, optical, thermal, mechanical and barrier properties. As the mechanism of action of these films is mainly based on release of the antimicrobial, this process was characterized when the active biofilms were exposed to three food simulants (water, 3% acetic acid, and 10% alcohol) at three temperatures (4, 23, and 37 °C). The data obtained revealed that, with the exception of exposure to water at 4 °C which achieved a release of more than 80% of the LAE incorporated, the agent was almost completely extracted in all conditions. Release of LAE was faster at higher temperatures, and the diffusion coefficient values varied according to the Arrhenius law, and increased with temperature. Antibacterial activity of films was assayed against Listeria monocytogenes and Escherichia coli. Zein films with 5% LAE produced 2.02 and 3.07 log reduction against L. monocytogenes and E. coli, respectively, after 5 days of storage at 4 °C. Greater antibacterial activity was observed with films containing 10% LAE (5 log reduction) at 37 °C. This work highlighted that LAE incorporation in a packaging film constructed with renewable polymer materials offers an interesting and efficient hurdle for control of bacterial contamination in foods., The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, projects AGL2012-39920-C03-01. M.K. thanks the Ministry of Sciences, Research and Technology of Iran for her grant. I.D. thanks the CSIC for her postdoctoral contract (JAE-DOC).

[EN] This study aims to develop antimicrobial films consisting of chitosan and silver nanoparticles that are homogeneously distributed throughout the polymer matrix. Nanoparticles were generated in situ during the neutralization of the chitosan acetate film with sodium hydroxide. The temperature of neutralization and the concentration of silver in the film were crucial determinants of the shape and size of the nanoparticles. Neutralized films exhibited antimicrobial activity against Escherichia coli and Staphylococcus aureus in liquid growth media. However, the effectiveness of the films was considerably greater in diluted growth media. Furthermore, no significant differences were found either in the antimicrobial capacities of films incorporating different amounts of silver or in the amount of silver that migrated into the liquid media after 18 h of immersion of the film. Neutralized films maintained their activity after 1 month of immersion in deionized water, which can be attributed to the slow sustained release of silver ions and thus efficacy over time., We thank the Spanish MICINN for financial support through Projects AGL-2009-08776 and Ingenio-Consolider CSD2007-00063 and the JAE program from CSIC (L.H. fellowship).

[EN] The aim of this work was to develop antimicrobial films for active packaging applications containing the natural antimicrobial compound LAE (lauramide arginine ethyl ester) in EVOH copolymers with different mol % ethylene contents (i.e. EVOH-29 and EVOH-44). EVOH-29 and EVOH-44 films were made by casting and incorporating 0.25%, 1%, 5%, and 10% LAE in the film forming solution (w/w with respect to polymer weight). Previously, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of LAE against Listeria monocytogenes, Escherichia coli, and Salmonella enterica were determined by a microdilution assay. The antimicrobial activity of the resulting films was tested in vitro against these microorganisms in liquid culture media. The activity of the films was also evaluated over time. The results showed that films containing 5% and 10% LAE produced total growth inhibition and viable counts decreased with 0.25% and 1% LAE. Finally, the effectiveness of the films was tested by applying them to an infant formula milk inoculated with L monocytogenes and S. enterica and stored for 6 days at 4 degrees C. The application of films with LAE to infant formula milk inoculated with L monocytogenes reduced at the end of storage period about 4 log in case of 10% LAE and with S. enterica reduced 3.74 log and 3.95 log with EVOH 29 5% and 10%, respectively, and EVOH-44 5% and 10% LAE reduced 1 log and 3.27 log, respectively, at the end of storage. The antimicrobial capacity of EVOH-29 films was greater than that of EVOH-44 films in all the cases tested. In general, the films were more effective in inhibiting the growth of L monocytogenes than S. enterica, this inhibition being more acute at the end of the storage time. (C) 2012 Elsevier B.V. All rights reserved., The authors acknowledge the financial support of the Spanish Ministry of Science and Innovation, project AGL2009-08776, and V. M.-G.'s fellowship.

The development of antioxidant active packaging systems is attracting considerable attention as one of the preferred emerging technologies for reducing the incidence of lipid peroxidation. This work presents the use of ethylene vinyl alcohol copolymer films containing two natural flavonoids, catechin and quercetin, to reduce the oxidation of food. In a series of experiments, these materials showed their ability to reduce the presence of hydroxyl radicals in the package headspace. Packaging fried peanuts in bags manufactured with these active films resulted in a large reduction in the presence of hexanal, a compound produced during peroxidation of the unsaturated fat in peanuts. The results indicated that the materials actively reduced the presence of radical oxidative species although the antioxidants are not released into the food. On exposing sunflower oil to the films, the peroxide values obtained showed that the films actively protected the oil; because of the higher solubility of quercetin in this food product as well as the higher antioxidant capacity, the samples containing this flavonoid were more efficient. Industrial relevance: Active packaging is receiving considerable attention as an emerging technology that can be used to improve the quality and the stability of food, reducing the direct addition of chemicals and the need for changes in formulation. The results of this study show that it is possible to reduce food oxidation without adding antioxidants to the food. The films obtained can be used to protect any type of food, including dry or fatty products. Copyright © 2012 John Wiley & Sons, Ltd. Received 12 April 2011; Revised 20 December 2011; Accepted 21 December 2011

Ethyl lauroyl arginate (LAE) is a cationic surfactant, which is considered one of the most potent antimicrobial substances among novel food additives. It presents a broad spectrum of activity against bacteria, yeasts, and molds. The high antimicrobial properties of LAE have been attributed to its action on the cell membranes of microorganisms. Furthermore, LAE has been classified as non-toxic because it is hydrolyzed in the human body and metabolized rapidly into natural components. The potential use of LAE as an antimicrobial agent can include a wide range of food. Also, several studies have been related with the application of LAE in antimicrobial packaging systems, showing a great potential to improve the safety and quality of packaged food products.

Chitosan films filled with hydroxypropyl-β-cyclodextrin at a 1:1 weight ratio and plasticized with 35 or 50% glycerol or 35% propylene glycol were prepared by casting and conditioned at different relative humidities to achieve a similar water content. Sorption properties of the films for various monoterpene compounds with phenolic, or with linear or cyclohexyl alcohol structures were studied after their immersion in the volatile liquids. In general, the films presented a considerable capacity to retain monophenolic compounds, with sorption values ranging from 455% for meta-cumenol to 193% for guaiacol, for chitosan films with the same formulation. These values were two orders of magnitude higher than those of compounds without the phenol group. The affinity for monophenolic compounds decreased in films plasticized with hydrophilic propylene glycol, whereas no changes were observed in the retention of non-phenolic monoterpenes. Replacement of chitosan with polyvinyl alcohol polymer considerably decreased the retention of monophenolic compounds, with the exception of isoeugenol. Finally, the antimicrobial activity of monoterpenes and films loaded with them was evaluated in vitro by the microatmosphere test against Escherichia coli and Staphylococcus aureus. The present study shows that hydroxypropyl-β-cyclodextrin and the plasticization level achieved by hydrophilic films can be used to regulate loading capacity and sorption selectivity of naturally occurring antimicrobial compounds., The authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO, AGL2012-39920-C03-01 and AGL2015-64595-R projects). Laura Higueras thanks the Spanish National Research Council for a JAE-PreDoc Fellowship.

[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 required, The 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).

The ethylene-vinyl alcohol copolymers (EVOHs) are well-known high oxygen barrier materials that are being used successfully in the design of packaging structures for oxygen-sensitive food or pharmaceutical products. Recently, there has been increasing interest in using EVOH materials to provide a high barrier to organic compounds as a means to reduce food aroma scalping. However, the barrier function of this family of materials diminishes significantly in humid environments, and it is supposed that so does the organic vapor barrier. In this work, a new sorption-based method to characterize the interaction between food aroma and polymer films for packaging as a function of relative humidity is presented and is used to determine the barrier to ethyl butyrate and alpha-pinene of EVOH at 23 degrees C. The results show that although EVOH is an excellent barrier to food aroma when dry, a property that even improves at low relative humidity (RH), the solubility and diffusivity of the compounds tested increase dramatically with humidity at medium to high water activities. However, even in the worst case (100% RH), EVOH outperforms low-density polyethylene (LDPE) as a barrier to organic vapors at least 500,000-fold.

[EN] Chitosan incorporating hydroxypropyl-beta-cyclodextrins and glycerol films capable of modulating loading capacity and release of carvacrol have been developed. Films were obtained by casting and conditioned at different relative humidities (RH) prior to immersion in liquid carvacrol. Incorporation of cyclodextrins in the chitosan matrix slightly increased sorption of carvacrol and it was necessary to use glycerol and water as coadjuvants to control loading of the films with the volatile. Good agreement was found between carvacrol retention and plasticization of the film by glycerol and water. The kinetics of carvacrol sorption by the films was evaluated at 25 degrees C. Diffusion coefficients of sorption varied from 0.011 x 10(-14) m(2)/s for films incorporating 35% glycerol and conditioned at 0% RH to 1.9 x 10(-14) m(2)/s for films incorporating 35% glycerol and conditioned at 75% RH. Release of carvacrol from the films was greatly affected by RH. The films showed antimicrobial activity against Staphylococcus aureus and Escherichia coli after 20 days of storage at 25 degrees C and 43% environmental RH. These films could be useful in the design of systems for delivering active volatiles. (C) 2014 Elsevier Ltd. All rights reserved., The authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO, AGL2012-39920-C03-01 project). Laura Higueras thanks the Spanish National Research Council for a JAE-PreDoc Fellowship.

[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.

[EN] A contact probe methodology, based on the voltammetry of immobilized microparticle approach, is used for characterizing silver species present in linear low density polyethylene (LLDPE) films with different Ag(I)/Ag(0) ratios and silver nanoparticle features usable as food contact polymers. The films displayed characteristic voltammetric features in contact with aqueous acetate buffer, in particular signals for the stripping oxidation of nanoparticulate Ag systems. Significant differences between the studied films were also observed by means of electrochemical impedance spectroscopy and detected at the nanoscopic scale using electrochemical scanning microscopy. Differences in optical and thermal properties of the studied films are associated with the presence of silver nanoparticles. The silver oxidation state as well as nanoparticle size also had influence on the oxidative resistance of the LLDPE films; indeed, films containing cationic silver showed the lowest oxidation induction time value., The authors wish to thank the Spanish Ministry of Science and Innovation for financial support through projects INGENIO-CONSOLIDER CSD2007-00063, AGL-2012-39920-C03-01, and CTQ2011-28079-C03-02, supported by ERDF funds, and Mr. Tim Swillens (translation services). I. D. thanks the CSIC for the postdoctoral contract concession.

[EN] Polymer films based on ethylene vinyl copolymers (EVOH) containing a 29 % (EVOH 29) and a 44 % molar percentage of ethylene (EVOH 44), and incorporating epsilon-polylysine (EPL) at 0 %, 1 %, 5 % and 10 % were successfully made by casting. The optical properties and the amount of EPL released from the films to phosphate buffer at pH 7.5 were evaluated, films showing great transparency and those of EVOH 29 copolymer releasing a greater amount of EPL. The antimicrobial properties of the resulting films were tested in vitro against different foodborne microorganisms and in vivo in surimi sticks. With regard to the antimicrobial capacity tested in vitro in liquid medium at 37 A degrees C and 4 A degrees C against Listeria monocytogenes and Escherichia coli over a period of 72 h, films showed a considerable growth inhibitory effect against both pathogens, more notably against L. monocytogenes, and being EVOH 29 more effective than EVOH 44 films. At 37 A degrees C, total growth inhibition was observed for EVOH 29 films incorporating 10 % EPL against both microorganisms whereas the copolymer EVOH 44 did show total inhibition against L. monocytogenes and the growth of E. coli was reduced by 6.64 log units. At 4 A degrees C, no film was able to inhibit completely bacterial growth. Scanning electron microscopy micrographs showed corrugated cell surfaces with blisters and bubbles, and collapse of the cells appearing shorter and more compact after treatment with EPL. Finally, the films were successfully used to increase the shelf life of surimi sticks. The results show the films developed have a great potential for active food packaging applications., The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, projects AGL2012-39920-C03-01, and fellowship funding for V. M.-G.

[EN] Chitosan (CS) films incorporating the antimicrobial compound ethyl-N-alpha-dodecanoyl-L-arginate (LAE) were developed for food packaging applications. Cast chitosan films were made with 1, 5 or 10% LAE and 20% glycerol in the film forming solution. Optical properties, release of LAE and antimicrobial activity of developed films was determined, The minimum inhibitory concentration (MIC) and the minimum biocide concentration (MBC) of LAE were determined. CS films with LAE were transparent and uniform, without discontinuities or visible particles and no visual differences could be perceived between CS and CS-LAE films. When in contact with an aqueous food simulant, the agent was fully released following a Fickian behavior in a few hours at 4 and 28 T. Antimicrobial activity of films against mesophiles, psychrophiles, Pseudomonas spp., colifoms, lactic acid bacteria, hydrogen sulfide-producing bacteria, yeast and fungi, was evaluated at two, six and eight days for its application on chicken breast fillets. Films were active against bacteria, yeasts and fungi in liquid and solid media. CS films evidenced antimicrobial activity in the range 0.47-2.96 log reductions, while CS-5%LAE film produced 1.78-5.81 log reduction. Results highlighted that LAE incorporation in a chitosan-based packaging structure may provide a relevant antimicrobial activity that could improve the stability of fresh poultry products. (C) 2013 Elsevier B.V. All rights reserved., Authors thank the financial support of the Spanish Ministry of Science and Innovation (projects AGL2009-08776, AGL2012-39920-CO3-01), EU (Nafispack project 212544), and JAE program from CSIC (L.H. fellowship) and Mr. Karel Clapshaw (translation services)., Ministerio de Ciencia e Innovación (MICINN)

[EN] Novel films of ethylene-vinyl alcohol copolymer (EVOH) containing flavonoid-rich cocoa were developed. To understand their potential application as active packaging material, antioxidant and antimicrobial properties of the films were determined as well as the antioxidant activity of the release compounds in Caco-2 human epithelial colorectal adenocarcinoma cells. Exposure of the films to aqueous food simulant showed antioxidant capacity. The release of cocoa extract components was dependent on the antioxidant concentration incorporated in the film and on temperature. Cocoa extract and the fraction obtained after in vitro gastrointestinal digestion presented antioxidant activity against oxidative stress induced by hydrogen peroxide in Caco-2 cells. Films with 10%, 15%, and 20% cocoa extract produced bactericidal effect against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Salmonella enterica. The application of films to an infant milk formula, previously inoculated with L. monocytogenes, inhibited the growth of bacteria 1.5 log units the first day and showed sustained release, inhibiting 0.52 and 0.76 log units, respectively, by the sixth day, while cocoa powder added directly did not produce any effect. Published by Elsevier Ltd., The authors 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). Karel Clapshaw provided assistance with the English language text.

[EN] The aim of this work was to design new polymer-based systems exhibiting an adjustable loading capacity of carvacrol depending on the film formulation. For this purpose, biocomposite films were developed employing chitosan (CS) as the polymer matrix and hydroxypropyl--cyclodextrins (HP-CDs) as an adjuvant to improve the sorption of carvacrol in the polymer matrix. The morphology, optical, mechanical and barrier properties of the resulting films were investigated, and the sorption capacity of carvacrol evaluated. Biocomposites resulted highly transparent with higher mechanical resistance and moisture barrier properties. Sorption of carvacrol was greatly affected by the humidity (RH) and glycerol (G) content of the biocomposites. The highest sorption values were achieved for composites incorporating 35% glycerol and conditioned at 75% these composites retained 216% carvacrol (g/100 g dry matter). These results indicate that inclusion of carvacrol in the films could be occurring by mechanisms other than formation of inclusion complexes., Authors thank the financial support of the Spanish Ministry of Science and Innovation (projects AGL2009-08776), JAE program from CSIC (L.H. fellowship), Generalitat Valenciana (J.P.C. fellowship).

Active antimicrobial packaging can be defined as a packaging system that interacts with the food product or the surrounding headspace either to kill the microorganisms that might be present in the food product or food package, or to reduce, inhibit or retard their growth. This chapter reviews: (a) the diverse families of antimicrobial compounds, their mode of action and their aptitude to be processed and be part of a packaging system; (b) the diverse techniques used to include the agents into the packaging materials, reduce their degradation and facilitate their action and the issues to be considered in packaging design; and (c) the diverse methods which can be applied to determine the activity of the wide range of antimicrobial packaging items.

[EN] The aim of the present work was to characterize the antimicrobial efficiency of films consisting of PP/EVOH structures with oregano essential oil and citral. Both substances are known for their antimicrobial activity based on their interaction with the cell membrane. The films developed were used to pack minimally processed salads, combining modified atmosphere technology to extend shelf-life and active packaging technology to reduce possible microbiological risks. The antimicrobial activity of the films against the pathogenic microorganisms Escherichia coli, Salmonella enterica and Listeria monocytogenes and natural microflora was investigated "in vitro" and also on the food itself. The effect of release of the antimicrobial agent on the sensory characteristics of the salad was also studied. The results showed that antimicrobial activity reduced spoilage flora on the salad as well as inhibited the growth of pathogens in contaminated salads. This effect was greater against Gram-negative bacteria. Sensory studies showed that the package that was most effective and most accepted by customers was the one containing 5% oregano essential oil. (C) 2012 Elsevier B.V. All rights reserved., The authors acknowledge the financial support of the Spanish Ministry of Science and Innovation, project AGL2009-08776, V. M.-G.'s fellowship from the Generalitat Valenciana, and J. P.-C.'s fellowship from the European Commission, Nafispack Project.

[EN] Films made of sodium caseinate containing lysozyme where modified by chemical or biochemical crosslinkers to achieve a controlled release of the antimicrobial lysozyme. Kinetic studies in buffered solutions at pH 3.02-5.80 were undertaken. Both the pH and the use of crosslinkers had a strong effect on the protein network, and consequently, a significant influence on the releasing of lysozyme activity. Sodium caseinate (NaCas) films became insoluble networks at pHs close to the isoelectric point of caseinate (pH 4.6), therefore decelerating remarkably the diffusion of lysozyme without the addition of crosslinkers. Additionally a slow release of lysozyme was achieved after mixing with glyoxal, achieving a modulation in the antimicrobial activity against Micrococcus lysodeikticus and Staphylococcus aureus. Other crosslinkers, as calcium chloride or transglutaminase, almost blocked enzyme release and were not found adequate to achieve enough antimicrobial activity. Results showed that active caseinate films modified by pH and glyoxal efficiently retarded the release of lysozyme, being a promising way to extend antimicrobial effects during food storage and to enhance food safety. (C) 2009 Elsevier Ltd. All rights reserved., Authors thank the Spanish Comision Interministerial de Ciencia y Tecnologia for financial support under contract AGL07-65936-C02 and the Consolider Project Fun-C-Food CSD2007-00063 from the Spanish Ministry of Science an Innovation. P. M. de Souza thanks the Generalitat Valenciana for Grant number BFPI/2008/230. A. Fernandez thanks the Ramon y Cajal program from MICINN.

[EN] Silver nanoparticles have been formed in fluff pulp and nanostructured Lyocell fibres by immersion in silver nitrate, and a subsequent transformation of the adsorbed silver ions into elementary silver nanoparticles by physical (thermal/UV) or chemical (sodium borohydride) methods. Microscopy revealed that nanoparticles generated by physical methods were regular in shape and efficiently dispersed, while the chemical reduction produced highly aggregated nanoparticles. Nanoparticle size has been found relevant to guarantee high antimicrobial activity, being the samples with big aggregated silver nanoparticles almost inefficient. Indeed a satisfactory correlation between silver ion release and the antimicrobial efficiency against Escherichia coli and Staphylococcus aureus could be confirmed, and furthermore, the highest concentrations tested were efficient to reduce the microbial load in poultry exudates. This work demonstrates that especially designed absorbent materials could be optimised to preserve aseptic conditions during manipulation, leading to feasible applications of a silver based nanotechnology in food technology., Authors thank the Spanish Comision Interministerial de Ciencia y Tecnologia (Ministerio de Ciencia a Innovacion) for financial support under contract AGL07-65936-C02. Authors are indebted to the members of the Laboratory for Metallic Contamination (IATA, CSIC), and especially to D. Velez, V. Devesa and M. Calatayud, for technical assistance for GFAAS and helpful discussions. A. Fernandez thanks the Ramon y Cajal Program for financial support.

[EN] The aim of this work was to develop antimicrobial photosensitizer-containing edible films and coatings based on gelatin as the polymer matrix. incorporating sodium magnesium chlorophyllin (E-140) and sodium copper chlorophyllin (E-141). Chlorophyllins were incorporated into the gelatin film-forming solution and the inhibiting effect of the cast films was tested against Staphylococcus aureus and Listeria monocytogenes. The results demonstrated that water soluble sodium magnesium chlorophyllin and water soluble sodium copper chlorophyllin reduced the growth of S. aureus and L monocytogenes by 5 log and 4 log respectively. Subsequently, the activity of self-standing films and coatings containing E-140 was assessed on cooked frankfurters inoculated with S. aureus and L monocytogenes. These tests showed that it was possible to reduce microorganism growth in cooked frankfurters inoculated with S. aureus and L monocytogenes by covering them with sodium magnesium chlorophyllin-gelatin films and coatings., The authors would like to thank I. Galdeano for technical support. They are also grateful for the financial support of the Generalitat Valenciana (Project GV04B-194) and the Spanish Ministry of Education and Science (project AGL2003-07326-C02-01).

8 pages, 2 figures, 2 tables.--PMID: 15124220 [PubMed], The intrinsic absorption of salbutamol in different intestinal segments of the rat was measured and related with the corresponding intestinal P-glycoprotein (P-gp) expression levels. The apparent absorption rate constants (ka, h-1) observed in each fraction by means of the in situ rat gut absorption method after perfusion of a 0.29-mM isotonic solution of salbutamol were used as absorption indexes. In a separate series of studies, a semiquantitative analysis of the mRNA expression of P-gp by means of polymerase chain reaction and Western blot with an antibody raised against the P-gp were also performed. The in situ ka values determined in the different segments (h-1) showed that the absorption is not homogeneous along the intestinal tract, that is, 0.499 ± 0.054 for colon, 0.474 ± 0.052 for the proximal segment, 0.345 ± 0.014 for the mean, and 0.330 ± 0.023 for the distal fraction. Addition of verapamil to the perfusion fluid did provide a better absorption of salbutamol in the distal segment. The analysis of the mRNA expression and levels of P-gp showed that the enzyme content in each section of the intestine was inversely related to salbutamol absorption, This work was supported by the CICYT of the Ministry of Education and Science of Spain (Projects SAF 96-1710 to A.M.-V. and PM 96-0074 to D.B.). The authors are indebted to the University of Valencia for a grant to B.V. (500th Centenary) and to the Conselleria de Cultura de Educación y Ciencia de la GV for a grant to G.L.-C. The authors are grateful to Laboratories Aldo-Unión (Barcelona, Spain) for supplying salbutamol.