ANTIFUNGAL CHITOSAN-BASED FILMS AND COATINGS CONTAINING ESSENTIAL OILS FOR FRUIT APPLICATIONS

Tesis por compendio[EN] Chitosan films and coatings have been obtained, by incorporating different essential oils (EO) and using different homogenization conditions of the film forming emulsions, in order to obtain antifungal materials for fruit preservation. The effect of oleic acid (OA) on the stability of the initial emulsions and on the film properties was analysed. Coatings were applied to control fungal decay in strawberries. The blending of chitosan with methylcellulose (MC) was also used in coating applications to tomato plants and fruits to prevent fungal infections. The films' functional properties as a function of their composition were analysed, as well as their antimicrobial activity through in vitro and in vivo tests. OA incorporation in the chitosan films (1:1 wt. ratio) reduced water vapour permeability (WVP) values to about 50 % of those of net chitosan films, with a small positive effect of the microfluidization process. EO (cinnamon, thyme and basil) did not notably reduced the WVP values of the chitosan films but a significant improvement in water barrier capacity was induced when OA was also added at 1:1 or 1:0.5 CH:OA ratios. In contrast, lipids slightly promoted oxygen permeability of the films. Lipid addition decreased the film stretchability and stiffness, with a lesser impact on the resistance to break, slightly depending on the droplet sizes. Essential oils also modulated the mechanical behaviour of the films, depending on their composition. Thyme and basil EO greatly promoted film stiffness and resistance to break, whereas cinnamon oil slightly reduced these mechanical attributes. Optical properties of the chitosan films were also affected by lipid incorporation. OA reduced the film transparency and gloss depending on the concentration, but provoked small changes in the colour parameters and whiteness index. EO affected transparency to a lesser extent, but had greater impact on the colour coordinates and whiteness index of the chitosan films due to the selective light absorption of their compounds. EO blend with oleic acid mitigated the colour changes in the films. Likewise, blending of OA with EO significantly reduced the losses of volatiles during the film formation due to the promotion of the stability of the film forming emulsions. Films containing cinnamon EO were effective in reducing the growth of Aspergillus niger, Botrytis cinerea and Rhizopus stolonifer, although thyme and basil EO encapsulated in the films did not exhibit antifungal action against these three fungi. When chitosan-cinnamon EO coatings were applied to strawberries inoculated with R. stolonifer, they reduced the fungal decay of the fruits during 14 days, at 10 °C, at the same time that total coliform counts were maintained at the initial levels. Chitosan coatings with lemon essential oil were also active at controlling fungal decay in strawberries. These did not significantly affect the physicochemical parameters of strawberries throughout cold storage, while they slowed down the respiration rate of the fruits and enhanced the chitosan antifungal activity against B. cinerea. The coatings, with and without lemon EO, affected the strawberry volatile profile, although it was only sensory appreciated for samples coated with chitosan-lemon oil. Blend films of CH and MC (1:1) containing oregano EO caused phytotoxic problems at "3 Leaves" stage of tomato plants, although the total biomass and crop yield was not affected. In the "Fruit" stage, the treatments had no negative effects. Coatings reduced the respiration rate of tomatoes, diminished weight loss during postharvest storage and were effective to decrease the fungal decay of tomatoes inoculated with R. stolonifer. Migration of thymol and carvacrol from CH-MC films in food simulants could overcome the stablished specific migration limit (60 mg/kg) for food contact packaging materials in aqueous and low pH systems if films contain a 1:1 polymer essential oil weight ratio.[ES] En la presente tesis doctoral se han desarrollado diferentes materiales antifúngicos para su uso en conservación de frutas. Para ello, se han incorporado diferentes aceites esenciales (AE) en recubrimientos y películas de quitosano (Q). Se ha analizado el efecto de la adición de ácido oleico (AO) y las condiciones de homogeneización sobre la estabilidad de las emulsiones y sobre las propiedades de las películas. Se ha estudiado el efecto de los recubrimientos de Q sobre el deterioro fúngico en fresas y el efecto preventivo frente a infecciones fúngicas de las mezclas de metilcelulosa (MC) con Q en plantas de tomate. Se ha estudiado el efecto de la composición de las películas sobre las propiedades funcionales de las mismas, así como su actividad antimicrobiana in vitro e in vivo. La incorporación de AO en las películas de Q (proporción 1:1) redujo la permeabilidad al agua (PVA) en un 50% comparado con la de Q puro. La microfluidización indujo un efecto positivo sobre dicha reducción. La adición de AE (hoja de canela, tomillo o albahaca) no supuso una disminución notable de los valores de permeabilidad obtenidos para las películas de Q. Cuando se añadió AO a las formulaciones de Q y AE (proporciones 1:1 o 1:2), se promovió una mejora significativa en la PVA de las películas. En cambio, la adición de lípidos aumentó ligeramente la permeabilidad al oxígeno, disminuyó la elasticidad y la rigidez, y produjo un menor impacto sobre la resistencia a la rotura. A su vez, la adición de AE modificó el comportamiento mecánico de las películas. Los AE de tomillo y albahaca aumentaron considerablemente la rigidez y la resistencia a la rotura, mientras que el AE de hoja de canela redujo estos parámetros ligeramente. La adición de lípidos a las películas de Q afectó las propiedades ópticas de las mismas. El AO redujo la transparencia y el brillo, en función de la concentración añadida. La adición de AE tuvo un mayor impacto sobre los parámetros de color y el índice de blancura. Las mezclas de AE y AO mitigaron estos cambios de color. Además, la incorporación de las mezclas AE-OA redujo las pérdidas de volátiles del AE durante la formación de las películas. Las películas formuladas con el AE de hoja de canela fueron efectivas contra el crecimientos de A. niger, B. cinerea y R. stolonifer, aunque los AE de tomillo y albahaca encapsulados en las películas no mostraron ninguna actividad antifúngica. La aplicación de los diferentes recubrimientos de Q AE de C en fresas inoculadas con R. stolonifer dio lugar a una reducción en el deterioro fúngico de los frutos almacenados durante 14 días a 10°C. Los recubrimientos de Q-AE de limón también fueron efectivos en el control del deterioro fúngico en fresas. Estos recubrimientos no afectaron significativamente los parámetros físico-químicos de las fresas durante el almacenamiento en refrigeración, disminuyeron la tasa de respiración de los frutos y acentuaron la actividad antifúngica del Q frente a B. cinerea. Tanto los recubrimientos con AE como los de Q puro modificaron el perfil de volátiles de las fresas, aunque estos cambios solo fueron apreciados sensorialmente en el caso de los frutos recubiertos con AE. Las mezclas de Q y MC que contenían AE de orégano causaron efectos fitotóxicos en plantas de tomate en el estadio "3 hojas", aunque no afectaron a la biomasa total. En el estadio "frutos" los tratamientos no tuvieron ningún efecto negativo. Los recubrimientos redujeron la tasa de respiración de los tomates, disminuyeron la pérdida de peso durante el almacenamiento post-cosecha y fueron efectivos contra el deterioro fúngico de tomates inoculados con R. stolonifer. La migración de los compuestos fenólicos timol y carvacrol, contenidos en las películas de Q-MC, podría superar el límite de migración específica establecido (60 mg/Kg) para materiales de envase en contacto con alimentos en los casos de sistemas acuosos y d[CA] En la present tesi doctoral s'han desenvolupat diferents materials antifúngics per al seu ús en conservació de fruites. Per a açò, s'han incorporat diferents olis essencials (OE) en recobriments i pel·lícules de quitosano (Q). S'ha analitzat l'efecte de l'addició d'àcid oleic (AO) i les condicions d'homogeneïtzació sobre l'estabilitat de les emulsions i sobre les propietats de les pel·lícules obtingudes. S'ha estudiat l'efecte dels recobriments de Q sobre la deterioració fúngica en maduixes i l'efecte preventiu enfront d'infeccions fúngiques de les mescles de metilcelulosa (MC) amb Q en plantes de tomaca. S'ha estudiat l'efecte de la composició de les pel·lícules sobre les propietats funcionals de les mateixes, així com la seua activitat antimicrobiana in vitro i in vivo. La incorporació de AO en les pel·lícules de Q (1:1) va reduir la permeabilitat al vapor d'aigua (PVA) en un 50% comparat amb la de Q pur. La microfluidització va induir un petit efecte positiu sobre aquesta reducció. L'addició de AE (fulla de canyella, C, timó, T, i alfàbrega, A) no va suposar una disminució notable dels valors de permeabilitat obtinguts per a les pel·lícules de Q. Quan es va afegir AO a les formulacions de Q i AE, es va promoure una millora significativa en la PVA de les pel·lícules. Per contra, l'addició de lípids va augmentar lleugerament la permeabilitat a l'oxigen, va disminuir l'elasticitat i la rigidesa, i va produir un menor impacte sobre la resistència al trencament. Al seu torn, l'addició de OE va modificar el comportament mecànic de les pel·lícules. Els OE de T i d'A van augmentar considerablement la rigidesa i la resistència al trencament, mentre que l'OE de C va reduir aquests paràmetres lleugerament. L'addició de lípids a les pel·lícules de Q també va afectar les propietats òptiques de les mateixes. L'AO va reduir la transparència i la lluentor, en funció de la concentració afegida. L'addició d'OE va tenir un major impacte sobre el paràmetres de color i l'índex de blancor. Les mescles d'OE i AO van mitigar aquests canvis de color. A més, la incorporació de les mescles OE-AO va reduir les pèrdues de volàtils de l'OE durant la formació de les pel·lícules. Les pel·lícules formulades amb l'OE de C van ser efectives contra el creixements d'A. niger, B. cinerea i R. stolonifer, encara que els OE de T i A encapsulats en les pel·lícules no van mostrar cap activitat antifúngica. L'aplicació dels diferents recobriments de Q OE de fulla de canyella en maduixes inoculades amb R. stolonifer va donar lloc a una reducció en la deterioració fúngica dels fruits emmagatzemats durant 14 dies a 10°C. Els recobriments de Q-OE de llimó també van ser efectius en el control de la deterioració fúngica en maduixes. Aquests recobriments no van afectar significativament els paràmetres fisicoquímics de les maduixes durant l'emmagatzematge en refrigeració, van disminuir la taxa de respiració dels fruits i van accentuar l'activitat antifúngica del Q enfront de B. cinerea. Tant els recobriments amb OE com els de Q pur van modificar el perfil de volàtils de les maduixes, encara que aquests canvis sol van ser apreciats sensorialment en el cas dels fruits recoberts amb OE. Les mescles de Q:MC que contenien OE d'orenga van causar efectes fitotòxics en plantes de tomaca en l'estadi "3 fulles", encara que no van afectar a la biomassa total. En l'estadi "fruits" els tractaments no van tenir cap efecte negatiu. Els recobriments van reduir la taxa de respiració de les tomaques, van disminuir la pèrdua de pes durant l'emmagatzematge post collita i van ser efectius contra la deterioració fúngica de tomaques inoculades amb R. stolonifer. La migració dels compostos fenòlics timol i carvacrol, continguts en les pel·lícules de Q-MC, podria superar el límit de migració específica establit (60 mg/Kg) per a materials d'envàs en contacte amb aliments en els casos de sistemes aquosos i dPerdones Montero, Á. (2015). ANTIFUNGAL CHITOSAN-BASED FILMS AND COATINGS CONTAINING ESSENTIAL OILS FOR FRUIT APPLICATIONS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59413TESISCompendi

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Effect on tomato plant and fruit of the application of biopolymer¿oregano essential oil coatings

[EN] BACKGROUND: Oregano essential oil (EO) was incorporated into film-forming dispersions (FFDs) based on biopolymers (chitosan and/or methylcellulose) at two different concentrations. The effect of the application of the FFDs was evaluated on tomato plants (cultivar Micro-Tom) at three different stages of development, and on pre-harvest and postharvest applications on tomato fruit. RESULTS: The application of the FFDs at '3 Leaves' stage caused phytotoxic problems, whichwere lethal when the EO was applied without biopolymers. Even though plant growth and development were delayed, the total biomass and the crop yield were not affected by biopolymer-EO treatments. When the FFDs were applied in the 'Fruit' stage the pre-harvest application of FFDs had no negative effects. All FFDs containing EO significantly reduced the respiration rate of tomato fruit and diminished weight loss during storage. Moreover, biopolymer-EO FFDs led to a decrease in the fungal decay of tomato fruit inoculated with Rhizopus stolonifer spores, as compared with non-treated tomato fruit and those coated with FFDs without EO. CONCLUSION: The application of biopolymer-oregano essential oil coatings has been proven to be an effective treatment to control R. stolonifer in tomato fruit. (C) 2016 Society of Chemical IndustryThe authors acknowledge the support provided by Universitat Politecnica de Valencia (SP20120518) and the Spanish Ministerio de Economia y Competitividad (AGL2013-42989-R-AR). Angela Perdones is grateful to Universitat Politecnia de Valencia for a FPI grantPerdones Montero, Á.; Tur, N.; Chiralt, A.; Vargas, M. (2016). Effect on tomato plant and fruit of the application of biopolymer¿oregano essential oil coatings. Journal of the Science of Food and Agriculture. 96(13):4505-4513. https://doi.org/10.1002/jsfa.7666S450545139613Ramos-García, M., Bosquez-Molina, E., Hernández-Romano, J., Zavala-Padilla, G., Terrés-Rojas, E., Alia-Tejacal, I., … Bautista-Baños, S. (2012). Use of chitosan-based edible coatings in combination with other natural compounds, to control Rhizopus stolonifer and Escherichia coli DH5α in fresh tomatoes. Crop Protection, 38, 1-6. doi:10.1016/j.cropro.2012.02.016Marti, E. (2006). Genetic and physiological characterization of tomato cv. Micro-Tom. Journal of Experimental Botany, 57(9), 2037-2047. doi:10.1093/jxb/erj154Lima, J. E., Carvalho, R. F., Neto, A. T., Figueira, A., & Peres, L. E. . (2004). Micro-MsK: a tomato genotype with miniature size, short life cycle, and improved in vitro shoot regeneration. Plant Science, 167(4), 753-757. doi:10.1016/j.plantsci.2004.05.023Meissner, R., Jacobson, Y., Melamed, S., Levyatuv, S., Shalev, G., Ashri, A., … Levy, A. (1997). A new model system for tomato genetics. The Plant Journal, 12(6), 1465-1472. doi:10.1046/j.1365-313x.1997.12061465.xMatusinsky, P., Zouhar, M., Pavela, R., & Novy, P. (2015). Antifungal effect of five essential oils against important pathogenic fungi of cereals. Industrial Crops and Products, 67, 208-215. doi:10.1016/j.indcrop.2015.01.022Bakkali, F., Averbeck, S., Averbeck, D., & Idaomar, M. (2008). Biological effects of essential oils – A review. Food and Chemical Toxicology, 46(2), 446-475. doi:10.1016/j.fct.2007.09.106Smith-Palmer, A., Stewart, J., & Fyfe, L. (2001). The potential application of plant essential oils as natural food preservatives in soft cheese. Food Microbiology, 18(4), 463-470. doi:10.1006/fmic.2001.0415Bendahou, M., Muselli, A., Grignon-Dubois, M., Benyoucef, M., Desjobert, J.-M., Bernardini, A.-F., & Costa, J. (2008). Antimicrobial activity and chemical composition of Origanum glandulosum Desf. essential oil and extract obtained by microwave extraction: Comparison with hydrodistillation. Food Chemistry, 106(1), 132-139. doi:10.1016/j.foodchem.2007.05.050Sari, M., Biondi, D. M., Kaâbeche, M., Mandalari, G., D’Arrigo, M., Bisignano, G., … Ruberto, G. (2006). Chemical composition, antimicrobial and antioxidant activities of the essential oil of several populations of AlgerianOriganum glandulosum Desf. Flavour and Fragrance Journal, 21(6), 890-898. doi:10.1002/ffj.1738Soylu, E. M., Kurt, Ş., & Soylu, S. (2010). In vitro and in vivo antifungal activities of the essential oils of various plants against tomato grey mould disease agent Botrytis cinerea. International Journal of Food Microbiology, 143(3), 183-189. doi:10.1016/j.ijfoodmicro.2010.08.015Tzortzakis, N. G. (2010). Ethanol, vinegar and Origanum vulgare oil vapour suppress the development of anthracnose rot in tomato fruit. International Journal of Food Microbiology, 142(1-2), 14-18. doi:10.1016/j.ijfoodmicro.2010.05.005Wogiatzi, E., Gougoulias, N., Papachatzis, A., Vagelas, I., & Chouliaras, N. (2009). Greek Oregano Essential Oils Production, Phytotoxicity and Antifungal Activity. Biotechnology & Biotechnological Equipment, 23(1), 1150-1152. doi:10.1080/13102818.2009.10817630Sánchez-González, L., Vargas, M., González-Martínez, C., Chiralt, A., & Cháfer, M. (2011). Use of Essential Oils in Bioactive Edible Coatings: A Review. Food Engineering Reviews, 3(1), 1-16. doi:10.1007/s12393-010-9031-3Tharanathan, R. N., & Kittur, F. S. (2003). Chitin — The Undisputed Biomolecule of Great Potential. Critical Reviews in Food Science and Nutrition, 43(1), 61-87. doi:10.1080/10408690390826455SHIEKH, R. A., MALIK, M. A., AL-THABAITI, S. A., & SHIEKH, M. A. (2013). Chitosan as a Novel Edible Coating for Fresh Fruits. Food Science and Technology Research, 19(2), 139-155. doi:10.3136/fstr.19.139Vargas, M., Pastor, C., Chiralt, A., McClements, D. J., & González-Martínez, C. (2008). Recent Advances in Edible Coatings for Fresh and Minimally Processed Fruits. Critical Reviews in Food Science and Nutrition, 48(6), 496-511. doi:10.1080/10408390701537344Nazan Turhan, K., & Şahbaz, F. (2004). Water vapor permeability, tensile properties and solubility of methylcellulose-based edible films. Journal of Food Engineering, 61(3), 459-466. doi:10.1016/s0260-8774(03)00155-9Vargas, M., Albors, A., Chiralt, A., & González-Martínez, C. (2011). Water interactions and microstructure of chitosan-methylcellulose composite films as affected by ionic concentration. LWT - Food Science and Technology, 44(10), 2290-2295. doi:10.1016/j.lwt.2011.02.018Badawy, M. E. I., & Rabea, E. I. (2009). Potential of the biopolymer chitosan with different molecular weights to control postharvest gray mold of tomato fruit. Postharvest Biology and Technology, 51(1), 110-117. doi:10.1016/j.postharvbio.2008.05.018Vargas, M., Albors, A., Chiralt, A., & González-Martínez, C. (2009). Characterization of chitosan–oleic acid composite films. Food Hydrocolloids, 23(2), 536-547. doi:10.1016/j.foodhyd.2008.02.009Perdones, Á., Vargas, M., Atarés, L., & Chiralt, A. (2014). Physical, antioxidant and antimicrobial properties of chitosan–cinnamon leaf oil films as affected by oleic acid. Food Hydrocolloids, 36, 256-264. doi:10.1016/j.foodhyd.2013.10.003Vargas, M., Albors, A., Chiralt, A., & González-Martínez, C. (2006). Quality of cold-stored strawberries as affected by chitosan–oleic acid edible coatings. Postharvest Biology and Technology, 41(2), 164-171. doi:10.1016/j.postharvbio.2006.03.016Perdones, A., Sánchez-González, L., Chiralt, A., & Vargas, M. (2012). Effect of chitosan–lemon essential oil coatings on storage-keeping quality of strawberry. Postharvest Biology and Technology, 70, 32-41. doi:10.1016/j.postharvbio.2012.04.002Hernández-Lauzardo, A. N., Velázquez-del Valle, M. G., Veranza-Castelán, L., Melo-Giorgana, G. E., & Guerra-Sánchez, M. G. (2010). Effect of chitosan on three isolates ofRhizopus stoloniferobtained from peach, papaya and tomato. Fruits, 65(4), 245-253. doi:10.1051/fruits/2010020Ghaouth, A. E., Ponnampalam, R., Castaigne, F., & Arul, J. (1992). Chitosan Coating to Extend the Storage Life of Tomatoes. HortScience, 27(9), 1016-1018. doi:10.21273/hortsci.27.9.1016Auerswald, H., Peters, P., Brückner, B., Krumbein, A., & Kuchenbuch, R. (1999). Sensory analysis and instrumental measurements of short-term stored tomatoes (Lycopersicon esculentum Mill.). Postharvest Biology and Technology, 15(3), 323-334. doi:10.1016/s0925-5214(98)00094-5Vargas, M., Chiralt, A., Albors, A., & González-Martínez, C. (2009). Effect of chitosan-based edible coatings applied by vacuum impregnation on quality preservation of fresh-cut carrot. Postharvest Biology and Technology, 51(2), 263-271. doi:10.1016/j.postharvbio.2008.07.019Kader AA Respiration and gas exchange of vegetables Postharvest Physiology of Vegetables Weichmann J Marcel Dekker New York 25 3

Eugenol and carvacrol migration from PHBV films and antibacterial action in different food matrices

[EN] The antibacterial effect of PHBV films with oregano or clove essential oil, or their main compounds, carvacrol (CA) and eugenol (EU), respectively, was analysed in food matrices (cheese, chicken breast and pumpkin and melon) and in vitro test for Escherichia coli and Listeria innocua. The migration of CA and EU in the different food matrices was determined to analyse the food matrix effect on the film¿s antimicrobial effectiveness. The antimicrobial activity in foods was less remarkable than in in vitro test. Despite the antilisterial effect in the in vitro test, this was not noticed in any food matrix. The most significant antibacterial effects against E. coli were observed in cheese and pumpkin, whereas the highest migration of both CA and UE took place in melon. This lack of correlation reflected that many compositional factors affect the active compound¿s availability to exert its antibacterial action in a specific food.The authors thank the Ministerio de Economía y Competitividad (Spain) for the financial support provided through Project AGL2016-76699-R. Author Raquel Requena thanks the Ministry of Education, Culture and Sport (Spain) for the FPU (FPU13/03444) Grant.Requena-Peris, R.; Vargas, M.; Chiralt A. (2019). Eugenol and carvacrol migration from PHBV films and antibacterial action in different food matrices. Food Chemistry. 277:38-45. https://doi.org/10.1016/j.foodchem.2018.10.093S384527

Physical, antioxidant and antimicrobial properties of chitosan cinnamon leaf oil films as affected by oleic acid

The physical, antioxidant and antimicrobial properties of chitosan (CH)-cinnamon leaf essential oil (C) films, containing or not oleic acid (OA), were evaluated. The addition of OA led an increase in surface charge and particle size of the film-forming dispersions. This is in agreement with a greater CH adsorption on the droplets containing OA and the entrapment of C compounds in the non-polar core of the OA molecule associations. OA contributed to a better retention of C in the film during its drying, diminished the changes in colour parameters provoked by C addition and reduced the film transparency. Water vapour permeability of CH films was reduced by OA incorporation while it increased when they contained only C. Every film containing C showed antioxidant and antifungal properties, depending on the C content (the higher the C content, the greater the effect). OA reduced the antifungal effectiveness of C containing films in line with its encapsulating effect on C compounds. All the coatings were effective in extending the shelf-life of cold-stored strawberries, mainly when CH was combined with C at the ratio 1: 0.5.The authors acknowledge the financial support provided by Universitat Politecnica de Valencia (UPPTE/2012/183) and Ministerio de Ciencia e Innovacion (AGL2010-20694). Author A. Perdones acknowledges Universitat Politecnica de Valencia for a doctoral grant.Perdones Montero, Á.; Vargas, M.; Atarés Huerta, LM.; Chiralt Boix, MA. (2014). Physical, antioxidant and antimicrobial properties of chitosan cinnamon leaf oil films as affected by oleic acid. Food Hydrocolloids. 36:256-264. https://doi.org/10.1016/j.foodhyd.2013.10.003S2562643

Antilisterial effect of citrus essential oils and their performance in edible film formulations

[EN] The antimicrobial activity of eight essential oils (EOs) extracted from the fruit peel of Citrus genotypes (orange, mandarin and lemon) was evaluated against 76 strains of Listeria monocytogenes, previously isolated from different food matrices. EOs showing the most (EO L2 and EO L8) and least (EO O3 and EO M7) effective inhibition activities were chemically characterized by gas chromatography coupled with mass spectrometry (GC/MS) to compare their composition. EO L2 and EO L8 were chosen to determine the MIC and to evaluate the cell viability of the most sensitive strains (L. monocytogenes LM35 and LM69) after 1, 2, 4 and 6 h of exposure. The effectiveness of chitosan (CH) and methylcellulose (MC) edible films, alone and in combination with EO L2 and EO L8, was determined against LM35 and LM69 at 37 C for 0, 8 and 24 h and at 8 C for 0, 1, 3 and 7 days. In addition, the analysis of the microstructure of the films were performed by scanning electron microscope (SEM) to evidence the interactions between the polymers and EOs. Thirty-five and twenty-nine strains were clearly inhibited by EO L2 and EO L8, respectively, while the other Citrus EOs showed poor (EO M1, O4, O5, O6) or minimal (EO O3 and M7) antimicrobial activity. A total of 36 chemical volatile substances was identified by GC/MS to detect the compounds that might play an important role in the characterization of the EOs. The chemical characterization points to oxygenated monoterpenes as relevant compounds in inhibiting Listeria strains, since they have been detected in lemon EOs in concentrations four/five folds higher than orange EOs. Generally, CH- and MCbased films containing EO L2 and EO L8 showed antilisterial activities, even though, the best performances were observed in case of CH-films at 8 C, with a major reduction up to 3 log (CFU/cm2) in case of EO L2 incorporation. The microstructures observed by SEM suggested a better incorporation of the EOs in CH matrix, where a higher amount of oil droplets was distinguished. Therefore, lemon EOs incorporated into chitosan films could be an efficient tool to control Listeria monocytogenes, especially in refrigerated applied conditions.WR was supported by the "Student Mobility for Placement - SMP" grant of the EU Life Learning Program. The authors thank the "Azienda Sperimentale Palazzelli C.R.A. - Centro di ricerca per l'agrumicoltura e le colture mediterranee Contrada Palazzelli Scordia" (CT, Italy) for providing some of the fruits used for EOs extractions.Randazzo, W.; Jiménez Belenguer, AI.; Settanni, L.; Perdones Montero, A.; Moschetti, M.; Palazzolo, E.; Guarrasi, V.... (2016). Antilisterial effect of citrus essential oils and their performance in edible film formulations. Food Control. 59:750-758. doi:10.1016/j.foodcont.2015.06.057S7507585

Use of oil-in-water emulsions to control fungal deterioration of strawberry jams

[EN] This work aimed to control the fungal deterioration of strawberry jams. The antifungal activity of the clove, cinnamon leaf, lemon and mandarin essential oils and their effectiveness in oil-in-water emulsions were evaluated. According to the results obtained, only clove and cinnamon leaf oils were selected to prepare emulsions. All the tested emulsions were stable, independently the amount of polymer and essential oil used. Essential oil loss was affected by the amount of polymer employed to prepare the emulsions. The oil-in-water emulsions with 5.0 mg/g xanthan gum, and with 0.55 mg/g clove or 0.65 mg/g cinnamon leaf essential oil, were used for the in vivo tests. The jams prepared with the oil-in-water emulsions showed a lower fungal decay compared with jams without emulsion. The present work demonstrated that emulsions can be employed to prevent strawberry jam mould spoilage.Author S. Ribes is grateful to the Universitat Politecnica de Valencia (UPV) for a FPI grant.Ribes-Llop, S.; Fuentes López, A.; Talens Oliag, P.; Barat Baviera, JM. (2016). Use of oil-in-water emulsions to control fungal deterioration of strawberry jams. Food Chemistry. 211:92-99. doi:10.1016/j.foodchem.2016.05.040S929921

Human milk from tandem feeding dyads does not differ in metabolite and metataxonomic features when compared to single nursling dyads under six months of age

Given the long-term advantages of exclusive breastfeeding to infants and their mothers, there is both an individual and public health benefit to its promotion and support. Data on the composition of human milk over the course of a full period of lactation for a single nursling is sparse, but data on human milk composition during tandem feeding (feeding children of different ages from different pregnancies) is almost entirely absent. This leaves an important knowledge gap that potentially endangers the ability of parents to make a fully informed choice on infant feeding. We compared the metataxonomic and metabolite fingerprints of human milk samples from 15 tandem feeding dyads to that collected from ten exclusively breastfeeding single nursling dyads where the nursling is under six months of age. Uniquely, our cohort also included three tandem feeding nursling dyads where each child showed a preferential side for feeding—allowing a direct comparison between human milk compositions for different aged nurslings. Across our analysis of volume, total fat, estimation of total microbial load, metabolite fingerprinting, and metataxonomics, we showed no statistically significant differences between tandem feeding and single nursling dyads. This included comparisons of preferential side nurslings of different ages. Together, our findings support the practice of tandem feeding of nurslings, even when feeding an infant under six months