Efecto de la incorporación de salvado de arroz sobre las propiedades fisicas y microestructurales de films biodegradables a base de almidón

[ES] En el presente trabajo se ha estudiado el efecto de la incorporación del salvado de arroz y de su tamaño, sobre las propiedades microestructurales y físicas (permeabilidad al vapor de agua y al oxígeno, propiedades ópticas y mecánicas) de films de almidón de guisante, patata y yuca, tras una y cinco semanas de almacenamiento a 25ºC-52,8%HR. Las propiedades mecánicas de los films se analizaron a 52,8% HR y la permeabilidad al vapor de agua a un gradiente de HR 52,8-100%. La opacidad o transparencia de los films se estudió a través del coeficiente de Kubelka-Munk obtenido del espectro de reflexión del film y el brillo se midió a 60º. Los resultados mostraron que tanto la incorporación de salvado, como su tamaño y el tiempo de almacenamiento modificaron las propiedades de los films. Así, la adición de salvado a la matriz de almidón hizo aumentar la humedad, el módulo de elasticidad y la permeabilidad al vapor de agua. Por el contrario la elongación y el brillo disminuyeron y la permeabilidad al oxígeno no se vio afectada. En general, estos cambios fueron más acusados al utilizar las partículas de salvado de mayor tamaño. Al final del almacenamiento, todas las variables se vieron notablemente afectadas: la humedad, la extensibilidad y la permeabilidad al oxígeno disminuyeron mientras que la rigidez y la resistencia a la rotura aumentaron, seguramente debido al proceso de retrogradación del almidón. Las micrografías muestran las fibras distribuidas de forma heterogénea en las secciones transversales y en la superficie, dando lugar a irregularidades estructurales que explican la menor resistencia mecánica y extensibilidad de estos films, junto con su menor brillo y transparencia.[CA] En el present treball s'ha estudiat l'efecte de la incorporació de segó d'arròs ila seua grandària, sobre les propietats microestructurals i físiques (permeabilitat al vapor d'aigua i al oxigen, propietats òptiques i mecàniques) de films de midó de pèsols, creïlla i iuca després d'una i cinc setmanes d'emmagatzemament 25C i 52,8% HR. Les propietats mecàniques dels films s'analitzaren a 52,8%HR i la permeabilitat al vapor d'aigua a un gradient de HR 52,8-100%. L'opacitat o transparència dels films es va estudiar mitjançant el coeficient de Kubelka-Munk obtingut de l'espectre de reflexió dels films i ela brillantor es va mesurar a 60º. Els resultats mostraren que tant la incorporació de segó, com la seua grandària i el temps d'emmagatzemament van modificar les propietats dels films. Així, l'adició de segó a la matriu de midó va augmentar la humitat, el mòdul d'elasticitat, la tensió a la fractura i la permeabilitat al vapor d'aigua, pel contrari l'elongació i la brillantor disminueix i la permeabilitat a l'oxigen no es veu afectada. En general, aquests canvis van ser més acusats al utilitzar les partícules de segó grandària major. A la fi de l'emmagatzemament totes les variables es van veure notablement afectades: la humitat, la extensibilitat i la permeabilitat a l'oxigen baixaren, pel contrari la rígides i la resistència al trencament pujaren. Les micrografies mostren les fibres distribuïdes de forma heterogènia en les seccions transversals i superficials, donant lloc a irregularitats estructurals que expliquen la menor resistència mecànica i extensibilitat dels films, junt amb la menor brillantor i transparència.[EN] In the present work the effect of incorporating the rice bran and its size on the microestructural and physical properties (water vapour and oxygen permeability, optical and mechanical properties) of pure pea, potato and cassava starch films, stored during one and five weeks (25ºC-52,8%RH), has been studied. The mechanical properties of the films have been tested at 52,8% RH, and the water vapour permeability has been measured at 52,8- 100 % RH gradient. The opacity or transparency of the films has been quantified by applying the theory of Kubelka-Munk and gloss has been measured at 60º. The results showed that bran addition, bran size and storage time modified the films properties. Thus, the addition of bran to pure starch matrix increased the moisture content, the elastic modulus and the water vapour permeability. On the contrary, the elongation and gloss values decreased and oxygen permeability was not affected. These changes were more pronounced when using the highest bran particle size. After five weeks of storage, all variables changed significantly. Moisture content, extensibility and oxygen permeability values decreased while stiffness and tensile strength values increased. Films micrographs showed fibers unevenly distributed throughout film matrix, leading to structural irregularities. This effect could explain the decrease of mechanical strength and extensibility, and low values of gloss and transparency of these composite films.Cano Embuena, AI. (2012). Efecto de la incorporación de salvado de arroz sobre las propiedades fisicas y microestructurales de films biodegradables a base de almidón. http://hdl.handle.net/10251/28005.Archivo delegad

Different strategies to improve the functionality of biodegradable films based on starch and other polymers

Tesis por compendio[EN] In the present Doctoral Thesis, different strategies to improve functional properties of starch films for food packaging applications were analysed: study of the effect of amylose:amylopectin ratio, blend with other polymers poly(vinyl alcohol) (PVA), and incorporation of different fillers (rice bran and cellulose nanocrystals-CNCs) and antimicrobial agents (neem oil-N, oregano essential oil-O and silver nanoparticles-AgNPs). Likewise, a biodegradation study of the films as affected by antimicrobials was carried out. Among different starches with distinct amylose:amylopectin ratio, pea starch was selected with higher values of this ratio. The high content of amylose gave rise to stiffer and more resistant to fracture films, with lower oxygen permeability, which decreased during storage. Pea starch-PVA (S-PVA) blend films represented a good strategy to improve film properties without a notable increase in cost. The PVA addition led to films which were less water soluble and not as sensitive to water sorption, more extensible and resistant than neat starch films, while they maintained the high oxygen barrier and provided stability to the matrix during ageing. In this sense, S-PVA ratios near to 1:1 are recommendable. When rice bran with the smallest particle size was used as filler, it improved the elastic modulus of the films, but reduced the film stretchability and barrier properties, due to the enhancement of the water binding capacity and the introduction of discontinuities in the matrix. Incorporation of CNCs into S-PVA films, as a reinforcing material, enhanced phase separation of polymers, did not imply changes in water vapour barrier of the films but improved the film mechanical performance: they became stiffer and more stretchable, while crystallization of PVA was partially inhibited. Silver loaded S-PVA films exhibited antimicrobial activity against the fungi (Aspergillus niger and Penicillium expansum) and bacteria (Listeria innocua and Escherichia coli) genera, depending on the silver concentration. Silver nanoparticles provoked notable changes in the film colour and transparency but no relevant changes in the other physical properties. Silver was completely delivered to aqueous simulants within the firsts 60 minutes of contact, but the film release capacity drastically decreased in the non-polar simulant, where the overall migration limit for food contact packaging materials (60 mg/Kg simulant) was accomplished. So, the use of the developed films as food packaging materials should be restricted to fat-rich foodstuffs. The incorporation of oregano essential oil (O), as antimicrobial agents, into the S-PVA matrix gave rise to active films against bacteria and fungi, whereas films containing neem oil (N) were not effective. Higher O concentration in the films was required to observe antifungal effect with respect to the antibacterial activity. Oils did not notably affect water sensitivity and water barrier properties of the films, but at high ratio, oils implied weaker film networks, affecting their mechanical performance. Blend of starch with PVA significantly improved PVA biodegradation and disintegration behaviour. Incorporation of silver species to S-PVA films slowed down their biodegradation kinetics while increased their degradation ratio. However, no significant effect of O was observed on the biodegradability indices despite the antimicrobial activity detected for this oil. N even promoted biodegradation of S-PVA films. Finally, a food application of biopolymer coatings was studied, using chitosan and essential oils (oregano or rosemary) to prevent weight loss and fungal development of semi-hard goat's milk cheeses. Coating were highly effective at reducing fungal growth and cheese weight loss while slightly reduced lipolytic and proteolytic activities in the cheese. Sensory evaluation revealed that the cheeses double coated with chitosan-oregano oil were the best evaluated in terms of aroma and flavour.[ES] En la Tesis Doctoral, se han analizado diferentes estrategias para mejorar las propiedades funcionales de películas de almidón para aplicaciones de envasado de alimentos: el estudio del ratio amilosa:amilopectina, mezclas con otros polímeros (alcohol de polivinilo-PVA), y la incorporación de diferentes refuerzos (salvado de arroz y nanocristales de celulose-CNCs) y agentes antimicrobianos (aceite de neem-N, aceite esencial de orégano-O y nanopartículas de plata-AgNPs). También se realizó un estudio de biodegradación de las películas observando el efecto de los antimicrobianos. Entre los diferentes almidones con distinto ratio amilosa:amilopectina, se seleccionó el almidón de guisante con altos valores de amilosa. El alto contenido en amilosa dio lugar a películas más rígidas y resistentes a la fractura, con baja permeabilidad al oxígeno, la cual disminuyó durante el almacenamiento. Las películas de mezcla de almidón-PVA (S-PVA) representaron una buena estrategia para mejorar las propiedades de las películas sin incrementar notablemente el precio. La adición de PVA dio lugar a películas menos solubles en agua, menos sensibles a su absorción y más extensible y resistentes que las de almidón puro, mientras mantuvieron alta barrera al oxígeno y dieron estabilidad a la matriz durante el envejecimiento. Son recomendables los ratios de S-PVA cercanos a 1:1. El salvado de arroz con menor tamaño de partícula, mejoró el modulo elástico de las películas, pero su extensibilidad y propiedades barrera empeoraron debido a la mejor capacidad de retención de agua y a las discontinuidades introducidas. La incorporación de CNCs en las películas de S-PVA incrementó la separación de fases de los polímeros, sin cambios en la permeabilidad al vapor de agua, y mejoró las prestaciones mecánicas: películas más rígidas y extensibles, mientras que inhibió parcialmente la cristalización del PVA. Las películas de S-PVA con partículas de plata exhibieron actividad antimicrobiana contra dos hongos y dos bacterias, dependiendo de la concentración de plata. Las AgNPs provocaron cambios en el color de las películas así como en su transparencia. La plata fue completamente liberada en los primeros 60 minutos en contacto con simulantes acuosos, sin embargo la liberación disminuyó en simulantes no polares, donde se cumple el límite de migración global. Por lo tanto, el uso de las películas desarrolladas para envasado de alimentos debe ser restringido a productos alimenticios ricos en grasas. La incorporación de O en la matriz de S-PVA dio lugar a películas activas contra bacterias y hongos, mientras que las películas con N no fueron efectivas. Se necesitaron concentraciones más altas de O en las películas para observar un efecto antifúngico respecto a la actividad bactericida. Los aceites no afectaron notablemente la sensibilidad ni las propiedades barreras al agua de las películas, aunque la mayor proporción de aceite dio lugar a películas con una red más débil, afectando sus prestaciones mecánicas. La mezcla de S con PVA mejoró significativamente el comportamiento de biodegradación y desintegración de las películas. La incorporación de AgNPs a películas de S-PVA disminuyó su cinética de biodegradación mientras aumentó su ratio de degradación. La adición de O no presentó efecto significativo en el índice de biodegradación a pesar de la actividad antimicrobiana detectada. El N incluso mejoró la biodegradación de las películas. Finalmente, se realizó una aplicación de recubrimientos basados en biopolímeros, usando quitosano-CH y aceite esencial de orégano o romero para evitar la pérdida de peso y el desarrollo de hongos en quesos de cabra semicurados. Los recubrimientos fueron efectivos en la reducción del crecimiento fúngico y la pérdida de peso de los quesos, mientras que la actividad lipolítica y proteolítica ligeramente disminuyó. El análisis sensorial reveló q[CA] S'han analitzat diferents estratègies per a millorar les propietats funcionals de pel·lícules de midó per a aplicacions d'envasat d'aliments: l'estudi de la ràtio amilosa:amilopectina, mescles amb altres polímers (alcohol polivinílic-PVA), i la incorporació de diferents reforços (segó d'arròs i nanocristalls de celulosa-CNCs) i agents antimicrobians (oli de neem-N, oli essencial d'orenga-O i nanopartícules de plata). També es va fer un estudi de biodegradació de les pel·lícules per observar l'efecte dels antimicrobians. Entre els diferents midons amb distint ràtio amilosa:amilopectina, es va seleccionar el midó de pèsol amb alts valors d'amilosa. L'alt contingut en amilosa va donar lloc a pel·lícules més rígides i resistents a la fractura, amb baixa permeabilitat a l'oxigen, la qual va disminuir durant l'emmagatzemament. Les pel·lícules de mescla de S-PVA van representar una bona estratègia per a millorar les propietats de les pel·lícules sense incrementar notablement el preu. L'addició de PVA va donar lloc a pel·lícules menys solubles en aigua, menys sensibles a la seua absorció i més extensible i resistents que les de midó pur. A més van mantenir l'alta barrera a l'oxigen i van donar estabilitat a la matriu durant l'envelliment. Son recomanables les ràtios de S- PVA pròxims a 1:1. El segó d'arròs amb menor tamany de partícula, va millorar el mòdul elàstic de les pel·lícules, però la seua extensibilitat i propietats barrera van empitjorar. La incorporació de CNCs en les pel·lícules de S-PVA, va incrementar la separació de fases dels polímers, sense implicar canvis en la permeabilitat al vapor d'aigua, però millorant les prestacions mecàniques: pel·lícules més rígides i extensibles, al mateix temps que es va inhibir parcialment la cristal·lització del PVA. Les pel·lícules de S-PVA amb partícules de plata van exhibir activitat antimicrobiana front a dos de fongs i dos bacteris, depenent de la concentració de plata. Les AgNPs van provocar canvis en el color de les pel·lícules així com en la seua transparència. La plata va ser completament alliberada en els primers 60 minuts en contacte amb simulants aquosos. La capacitat d'alliberament va disminuir en simulants no polars, on es complix el límit de migració global. Per tant, l'ús de les pel·lícules desenvolupades per a l'envasat d'aliments ha de ser restringit a productes alimentaris rics en greixos. La incorporació d'O en la matriu de S-PVA va donar lloc a pel·lícules actives front a bacteris i fongs. Pel contrari les pel·lícules amb N no van ser efectives. Van ser necessàries concentracions més elevades d'O en les pel·lícules per a observar un efecte antifúngic respecte a l'activitat bactericida. Els olis no van afectar la sensibilitat a l'aigua ni les propietats barrera a l'aigua de les pel·lícules, però la major proporció d'oli va donar lloc a pel·lícules amb una xarxa més dèbil, afectant les seues prestacions mecàniques. La mescla de S amb PVA va millorar significativament el comportament de biodegradació i desintegració. La incorporació de partícules de plata a pel·lícules de S-PVA va disminuir la seua cinètica de biodegradació mentre que va augmentar la seua ràtio de degradació. No obstant això, l'addició d'O no va presentar un efecte significatiu en els índexs de biodegradació a pesar de l'activitat antimicrobiana detectada. L'N fins i tot va millorar la biodegradació de les pel·lícules de S-PVA. Finalment, es va realitzar una aplicació de recobriments basats en biopolímers, fent ús de quistosà-CH i olis essencials de orenga i romer per evitar la pèrdua de pes i el desenvolupament de fongs en formatges de cabra semi-curats. Els recobriments van ser altament efectius en la reducció del creixement fúngic i la pèrdua de pes dels formatges. L'activitat lipolítica i proteolítica en els formatges va disminuir suaument. L'anàlisi sensorial va revelar que els formCano Embuena, AI. (2015). Different strategies to improve the functionality of biodegradable films based on starch and other polymers [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/55383TESISPremios Extraordinarios de tesis doctoralesCompendi

Physical and microstructural properties of biodegradable films based on pea starch and PVA

[EN] The effect of storage time on the physical properties of pea starch (PS) and polyvinyl alcohol (PVA) films and their blend was studied to develop biodegradable packaging materials for food applications. To this end, an analysis was performed of the microstructural and physical properties (solubility, moisture content, barrier, mechanical and optical properties) of PS, PVA and PS:PVA films stored for five weeks (25 C 53%RH). Whereas SEM micrographs showed a homogenous appearance for PS films, PVA presented irregularities typical of semi-crystalline structures. Blend films showed a structure which was more similar to PVA films. After 5 weeks, the physical properties of PVA films did not change; in the case of PS, however, the elastic modulus and tensile strength increased markedly but the stretchability and gloss significantly decreased, which was associated with water loss in the starch matrix. All the physical properties of blend films remained unchanged throughout time, except the elastic modulus and the tensile strength, which slightly increased. Therefore, the incorporation of PVA into pea starch films improved their physical properties and inhibited the changes that occurred in the starch matrix caused by ageing.The authors wish to acknowledge the finance support from the Spanish Ministerio de Economia y Competitividad throughout the project AGL2010-20694. Amalia Cano also thanks the Spanish Ministerio de Educacion, Cultura y Deporte for the FPU grant.Cano Embuena, AI.; Cháfer Nácher, MT.; Chiralt, A.; González Martínez, MC. (2015). Physical and microstructural properties of biodegradable films based on pea starch and PVA. Journal of Food Engineering. 167(1):59-64. https://doi.org/10.1016/j.jfoodeng.2015.06.0035964167

Biodegradation behavior of starch-PVA films as affected by the incorporation of different antimicrobials

The effect that the incorporation of different antimicrobial substances into S-PVA films had on their disintegration and biodegradation process was analysed. To this end, starch, PVA and S-PVA films containing different concentrations of neem oil, oregano essential oil and silver nanoparticles were submitted to composting conditions in order to determine the disintegration and biodegradability percentages for 73 and 45 days, respectively. Additionally, thermogravimetric and structural analyses were also carried out throughout the composting period. The biodegradation and disintegration behavior of S-PVA films was intermediate between S and PVA films. The addition of neem and oregano essential oils slightly affected the biodegradation and disintegration profile of starch-PVA films, enhancing both disintegration and biodegradation levels. So, the presence of these antimicrobials did not compromise the compostable and biodegradable character of the starch-PVA blend films. Nevertheless, the biodegradation capacity of films containing 9.8% silver species was seriously affected, reaching values of only 58% after 45 days of composting, despite their high disintegration capacity. Thus, lower silver concentrations are recommended in order to avoid possible alterations in compost microbial activity.The authors acknowledge the financial support from the Spanish Ministerio de Economia y Competitividad through the projects AGL2013-42989-R. Amalia Cano also thanks the Spanish Ministerio de Education, Cultura y Deporte for the FPU grant (AP2010-4377).Cano Embuena, AI.; Cháfer Nácher, MT.; Chiralt Boix, MA.; González Martínez, MC. (2016). Biodegradation behavior of starch-PVA films as affected by the incorporation of different antimicrobials. Polymer Degradation and Stability. 132:1-10. https://doi.org/10.1016/j.polymdegradstab.2016.04.014S11013

Effect of cellulose nanocrystals on the properties of pea starch-poly(vinyl alcohol) blend films

[EN] Incorporation of cellulose nanocrystals (CNC) to pea starch-poly(vinyl alcohol) (PVA) (1:2 ratio) blend films was carried out in order to improve their physical properties. Different ratios (1, 3 and 5 % wt) of CNC were used and structural, thermal and physical (barrier, mechanical and optical) properties were analysed in comparison to the control film without CNC. Incorporation of CNC enhanced phase separation of polymers in two layers. The upper PVA rich phase contained lumps of starch which emerged from the film surface, thus reducing the film gloss. CNC were dispersed in both polymeric phases as aggregates, whose size increased with the CNC ratio rise. CNC addition did not implied changes in water vapour barrier of the films, but they became slightly stiffer and more stretchable, while crystallization of PVA was partially inhibited.The authors acknowledge the financial support from the Spanish Ministerio de Economia y Competitividad throughout the Projects AGL2010-20694 and AGL2013-42989-R. Amalia Cano also thanks the Spanish Ministerio de Educacion, Cultura y Deporte for the FPU grant and COST-STSM-FA1001-14253 for the financial support for the collaboration.Fortunati, E.; Cano Embuena, AI.; Cháfer Nácher, MT.; González Martínez, MC.; Chiralt, A.; Kenny, J. (2015). Effect of cellulose nanocrystals on the properties of pea starch-poly(vinyl alcohol) blend films. Journal of Materials Science. 50(21):6979-6992. https://doi.org/10.1007/s10853-015-9249-9S697969925021Armentano I, Dottori M, Fortunati E, Mattioli S, Kenny JM (2010) Biodegradable polymer matrix nanocomposites for tissue engineering: a review. 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Quality of goats milk cheese as affected by coating with edible chitosan-essential oil films

[EN] The effectiveness of applying chitosan coatings containing rosemary and oregano essential oils to cheeses was analysed. Cheeses were coated by immersing the samples two or three times successively in the different formulations. The ripening indexes, water loss, fungal growth and sensory properties of the coated and noncoated cheeses throughout ripening were evaluated. The coatings both prevented weight loss and improved the microbial safety. The lipolytic and proteolytic activities were reduced in coated cheese, which is in line with the antimicrobial effect of active coatings. Sensory evaluation revealed that the cheeses double-coated with chitosan oregano oil were the best evaluated in terms of aroma and flavour.The authors wish to acknowledge the financing of the project by the Program of Support for Research and Development (PAID-05-12) of the Universitat Politecnica de Valencia.Cano Embuena, AI.; Cháfer Nácher, MT.; Chiralt, A.; Molina Pons, MP.; Borràs Llopis, M.; Beltrán Martínez, MC.; González Martínez, MC. (2017). Quality of goats milk cheese as affected by coating with edible chitosan-essential oil films. International Journal of Dairy Technology. 70(1):68-76. https://doi.org/10.1111/1471-0307.12306S6876701Aenor 1979 UNE 87-004-79: Sensory Analysis: A guide for the installation of a test roomAguirre, A., Borneo, R., & León, A. E. (2013). Antimicrobial, mechanical and barrier properties of triticale protein films incorporated with oregano essential oil. Food Bioscience, 1, 2-9. doi:10.1016/j.fbio.2012.12.001Bonilla, J., Talón, E., Atarés, L., Vargas, M., & Chiralt, A. (2013). Effect of the incorporation of antioxidants on physicochemical and antioxidant properties of wheat starch–chitosan films. Journal of Food Engineering, 118(3), 271-278. doi:10.1016/j.jfoodeng.2013.04.008Cerqueira, M. A., Lima, A. M., Souza, B. W. S., Teixeira, J. A., Moreira, R. A., & Vicente, A. A. (2009). Functional Polysaccharides as Edible Coatings for Cheese. Journal of Agricultural and Food Chemistry, 57(4), 1456-1462. doi:10.1021/jf802726dCerqueira, M. A., Sousa-Gallagher, M. J., Macedo, I., Rodriguez-Aguilera, R., Souza, B. W. S., Teixeira, J. A., & Vicente, A. A. (2010). Use of galactomannan edible coating application and storage temperature for prolonging shelf-life of «Regional» cheese. Journal of Food Engineering, 97(1), 87-94. doi:10.1016/j.jfoodeng.2009.09.019Chen, J. H., & Hotchkiss, J. H. (1993). Growth of Listeria monocytogenes and Clostridium sporogenes in Cottage Cheese in Modified Atmosphere Packaging. Journal of Dairy Science, 76(4), 972-977. doi:10.3168/jds.s0022-0302(93)77424-xCODEX STANDARD 2013 Codex General Standard for CheeseConselleria d'Agricultura, Pesca i Alimentació Conselleria de Agricultura, Pesca y Alimentación 2008 ORDER of 23th of december of 2008. CVConte, A., Gammariello, D., Di Giulio, S., Attanasio, M., & Del Nobile, M. A. (2009). Active coating and modified-atmosphere packaging to extend the shelf life of Fior di Latte cheese. Journal of Dairy Science, 92(3), 887-894. doi:10.3168/jds.2008-1500Duan, J., Park, S.-I., Daeschel, M. A., & Zhao, Y. (2007). Antimicrobial Chitosan-Lysozyme (CL) Films and Coatings for Enhancing Microbial Safety of Mozzarella Cheese. Journal of Food Science, 72(9), M355-M362. doi:10.1111/j.1750-3841.2007.00556.xEck A 1990 The cheese. Technique and documentationFajardo, P., Martins, J. T., Fuciños, C., Pastrana, L., Teixeira, J. A., & Vicente, A. A. (2010). Evaluation of a chitosan-based edible film as carrier of natamycin to improve the storability of Saloio cheese. Journal of Food Engineering, 101(4), 349-356. doi:10.1016/j.jfoodeng.2010.06.029Folkertsma, B., & Fox, P. F. (1992). Use of the Cd-ninhydrin reagent to assess proteolysis in cheese during ripening. Journal of Dairy Research, 59(2), 217-224. doi:10.1017/s0022029900030466Gonzalez, C., Fuentes, C., Andrés, A., Chiralt, A., & Fito, P. (1999). Effectiveness of vacuum impregnation brining of Manchego-type curd. International Dairy Journal, 9(2), 143-148. doi:10.1016/s0958-6946(99)00035-7Gripon, J. C. (1993). Mould-Ripened Cheeses. Cheese: Chemistry, Physics and Microbiology, 111-136. doi:10.1007/978-1-4615-2648-3_4Hocking, A. D. (2014). SPOILAGE PROBLEMS | Problems Caused by Fungi. Encyclopedia of Food Microbiology, 471-481. doi:10.1016/b978-0-12-384730-0.00315-3Kampf, N., & Nussinovitch, A. (2000). Hydrocolloid coating of cheeses. Food Hydrocolloids, 14(6), 531-537. doi:10.1016/s0268-005x(00)00033-3Lambert, R. J. W., Skandamis, P. N., Coote, P. J., & Nychas, G.-J. E. (2001). A study of the minimum inhibitory concentration and mode of action of oregano essential oil, thymol and carvacrol. Journal of Applied Microbiology, 91(3), 453-462. doi:10.1046/j.1365-2672.2001.01428.xLIEWEN, M. B., & MARTH, E. H. (1985). Growth and Inhibition of Microorganisms in the Presence of Sorbic Acid: A Review. Journal of Food Protection, 48(4), 364-375. doi:10.4315/0362-028x-48.4.364Mannheim, C. H., & Soffer, T. (1996). Shelf-life Extension of Cottage Cheese by Modified Atmosphere Packaging. LWT - Food Science and Technology, 29(8), 767-771. doi:10.1006/fstl.1996.0120Mastromatteo, M., Conte, A., Faccia, M., Del Nobile, M. A., & Zambrini, A. V. (2014). Combined effect of active coating and modified atmosphere packaging on prolonging the shelf life of low-moisture Mozzarella cheese. Journal of Dairy Science, 97(1), 36-45. doi:10.3168/jds.2013-6999Nuñez, M., García-Aser, C., Rodríguez-Martin, M. A., Medina, M., & Gaya, P. (1986). The effect of ripening and cooking temperatures on proteolysis and lipolysis in Manchego cheese. Food Chemistry, 21(2), 115-123. doi:10.1016/0308-8146(86)90156-1Owolarafe, O. K., Olabige, T. M., & Faborode, M. O. (2007). Macro-structural characterisation of palm fruit at different processing conditions. Journal of Food Engineering, 79(1), 31-36. doi:10.1016/j.jfoodeng.2006.01.024Ramos, Ó. L., Pereira, J. O., Silva, S. I., Fernandes, J. C., Franco, M. I., Lopes-da-Silva, J. A., … Malcata, F. X. (2012). Evaluation of antimicrobial edible coatings from a whey protein isolate base to improve the shelf life of cheese. Journal of Dairy Science, 95(11), 6282-6292. doi:10.3168/jds.2012-5478Sánchez-González, L., González-Martínez, C., Chiralt, A., & Cháfer, M. (2010). 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Análisis de comportamiento del consumidor en el manejo de alimentos vegetales desde la tienda hasta el consumo

Los consumidores juegan un papel muy importante dentro del marco de la seguridad alimentaria, ya que la rutina que realizan desde que compran los alimentos hasta que los consumen puede condicionar la seguridad de los mismos. Las condiciones de transporte, almacenamiento en el hogar, manipulación y preparación son muy importantes en todos los alimentos en general, y en esencial en aquellos que no reciben ningún tratamiento previo a su consumo capaz de eliminar el riesgo microbiológico. Este artículo plantea como principal objetivo llegar a conocer las prácticas habituales de manipulación de vegetales, desde la compra hasta el consumo, por parte de los consumidores de la ciudad de Valencia. Los resultados muestran que es necesario realizar un importante esfuerzo de información por parte de las administraciones públicas; ya que aunque los consumidores afirman ser conscientes de su papel en la seguridad de alimentos y se consideran meticulosos, en cambio, algunas de las prácticas que realizan no son las adecuadas.Cano Embuena, AI. (2010). Análisis de comportamiento del consumidor en el manejo de alimentos vegetales desde la tienda hasta el consumo. http://hdl.handle.net/10251/11767Archivo delegad

Properties and ageing behaviour of pea starch films as affected by blend with poly(Vinyl Alcohol)

[EN] Pea starch (S) and poly(vinyl alcohol) (PVA) blends with different ratios were produced in order to elucidate the possible advantages of blend films to overcome the common drawbacks of starch films. Starch, poly(vinyl alcohol) and blends (S:PVA ratios of 2:1, 1:1 and 1:2) were obtained by casting and microstructure and thermal behaviour were characterized. Moreover, barrier, mechanical and optical properties were evaluated after 1 and 5 storage weeks at 25 ºC and 53 % relative humidity in order to study the effect of poly(vinyl alcohol) on the ageing process of starch. The incorporation of PVA into pea starch films implied the formation of interpenetrated networks of both incompatible polymers with partial solubilisation. S-PVA blend films were much more extensible and stable during storage, with improved water barrier properties and reduced water sorption capacity especially when the S:PVA ratio were 1:1 and 1:2. Starch-poly(vinyl alcohol) blend films are environmentally friendly, low cost materials, with good functional properties.The authors acknowledge the financial support from the Spanish Ministerio de Economia y Competitividad throughout the project AGL2010-20694, co-financed with FEDER funds. Amalia Cano also thanks the Spanish Ministerio de Educacion, Cultura y Deporte for the FPU grant and COST-STSM-FA1001-14253 for the financial support for the collaboration.Cano Embuena, AI.; Fortunati, E.; Cháfer Nácher, MT.; Kenny, J.; Chiralt, A.; González Martínez, MC. (2015). Properties and ageing behaviour of pea starch films as affected by blend with poly(Vinyl Alcohol). Food Hydrocolloids. 48:84-93. doi:10.1016/j.foodhyd.2015.01.008S84934