Encapsulación de aceites esenciales funcionales para su aplicación en agricultura

[EN] The application of microcapsules has been spread in recent years in many different sectors such as food, medical, cosmetic and textile due to the benefits that these systems have, with respect to the use of the unencapsulated active compounds. The microcapsules get a progressive and effective release of highly volatile to ensure their functionality over time molecules. Essential oils are volatile liquid fractions biosynthesized by plants that have very interesting properties, such as antimicrobial, insecticide or pesticide capacity. To take advantage of these properties of oils for use in agriculture, the microencapsulation has been studied by different techniques: spray drying, interfacial polymerization and co-extrusion/gelling, because each technique allows the use of a membrane material, and different operating conditions which result in microcapsules with very different properties. The microcapsules developed were characterized by using different techniques. Thermal analysis using Differential Scanning Calorimetry (DSC) has provided useful information about the thermal stability of the starting materials to select conditions most suitable microencapsulation process, and to determine the thermal stability of the microcapsules obtained. By using electron microscopy (SEM) state and morphology of the microcapsules were determined. Meanwhile, Fourier Transform Infrared Spectroscopy (FTIR) has corroborated the presence of essential oils inside the microcapsules, such as the antimicrobial trial performed. Parallel to the development of the microcapsules, obtaining a biodegradable textile substrate to serve as a vehicle for applying microcapsules has been studied. The textile substrate consisted of a nonwoven fabric made from hemp pruning waste with a high capacity for disintegration, which can be encompassed in the field of bio blankets application in agriculture. Microcapsules have been applied on the nonwoven fabric by applying a binder; in this case, the use of two completely biodegradable natural polymers was studied, given the final application substrate. Nonwoven fabrics have been characterized by different techniques, among them; the antimicrobial activity and resistance to weathering under real conditions were evaluated. With the development of this research it is intended to harness the potential provided by microencapsulation, in order to functionalize a product providing it with greater added value while maintaining the concept of sustainability.[ES] La aplicación de las microcápsulas se ha extendido en los últimos años en diversos sectores tan diferentes como el alimentario, médico, cosmético o textil por los beneficios que estos sistemas presentan, con respecto al empleo de los compuestos activos sin encapsular. Las microcápsulas consiguen una liberación progresiva y eficaz de moléculas altamente volátiles para garantizar su funcionalidad en el tiempo. Los aceites esenciales son fracciones liquidas volátiles biosintetizadas por las plantas que presentan propiedades muy interesantes, como su capacidad antimicrobiana, insecticida o pesticida. Con el fin de aprovechar estas propiedades de los aceites para su aplicación en agricultura, se ha estudiado su microencapsulación mediante diferentes técnicas: secado por atomización, polimerización interfacial y co-extrusión/gelificación, pues cada una de ellas permite el empleo de unos materiales membrana, y condiciones de operación diferentes que dan lugar a microcápsulas con propiedades muy diversas. Las microcápsulas desarrolladas han sido caracterizadas mediante diferentes técnicas. El análisis térmico realizado mediante análisis de calorimetría diferencial (DSC) ha proporcionado información útil sobre la estabilidad térmica de los materiales de partida para seleccionar las condiciones del proceso de microencapsulación más adecuadas, así como determinar la estabilidad térmica de las microcápsulas obtenidas. Mediante microscopía electrónica de barrido (SEM) se ha determinado el estado y morfología de las microcápsulas. Por su parte, la espectroscopia de infrarrojos (FTIR) ha permitido corroborar la presencia de los aceites esenciales en el interior de las microcápsulas, al igual que el ensayo antimicrobiano realizado. En paralelo al desarrollo de las microcápsulas, se ha estudiado la obtención de un sustrato textil biodegradable que sirva de vehículo para aplicar las microcápsulas. El sustrato textil ha consistido en un tejido no tejido, elaborado a partir de residuos de poda del cáñamo, con una elevada capacidad de desintegración, que puede englobarse en el campo de las bio-mantas de aplicación en agricultura. Las microcápsulas han sido aplicadas sobre el tejido no tejido mediante la aplicación de un ligante, en este caso se ha estudiado el uso de dos polímeros naturales completamente biodegradables, dada la aplicación final del sustrato. Los tejidos no tejidos han sido caracterizados mediante diferentes técnicas, entre ellas, se ha evaluado la capacidad antimicrobiana y, la resistencia a la intemperie en condiciones reales. Con el desarrollo de esta investigación se pretende aprovechar las posibilidades que la microencapsulación ofrece, con el fin de funcionalizar un producto dotándolo de un mayor valor añadido manteniendo el concepto de sostenibilidad.[CA] L' aplicació de microcàpsules s'ha estès al llarg dels últims anys a sectors industrials tan diferents com l'alimentari, cosmètic, mèdic o tèxtil, a causa dels beneficis que aquests sistemes presenten, respecte a l'ús dels compostos actius sense microencapsular. Les microcàpsules aconseguixen una alliberació eficaç i gradual de molècules molt volàtils que garantix la seua funcionalitat al llarg del temps. Els olis essencials són fraccions líquides volàtils biosintetitzades per les plantes que tenen propietats molt interessants, com antimicrobianes, insecticides o pesticides. Amb la finalitat d'aprofitar aquestes propietats dels olis per a la seua aplicació en agricultura, s'ha estudiat la seua microencapsulació mitjançant diferents tecnologies: assecament per polvorització, polimerització interfacial i co-extrusió/gelificació, ja que cadascuna d'elles permet l'ús d'uns materials membrana, així como d'unes condicions d'encapsulació diferents que donen lloc a microcàpsules amb propietats molt concretes. Les microcàpsules desenvolupades han sigut caracteritzades mitjançant diferents tècniques. L'anàlisi tèrmic realitzat per calorimetria diferencial (DSC) ha permès obtindre informació útil sobre l'estabilitat tèrmica dels materials per tal de seleccionar les condicions de procés per a la microencapsulació més optimes. Mitjançant la microscòpia electrònica de barreig (SEM) s'ha obtés informació de l'estat i morfologia de les microcàpsules. D'altra banda, l'Espectroscòpia Infraroja per Transformada de Fourier (FTIR) corroborà la presència dels olis a l'interior de les microcàpsules, així com també ho feu l'assaig antimicrobià. Paral·lelament al desenvolupament de les microcàpsules s'ha estudiat l'obtenció d'un substrat tèxtil biodegradable, per utilitzar-lo com a vehicle per aplicar les microcàpsules. Aquest substrat tèxtil ha estat format per un teixit no teixit obtés a partir de residus de les plantes de cànem, amb gran capacitat de desintegració, el qual pot classificar-se dintre de les conegudes com a bio mantes d'aplicació en agricultura. Les microcàpsules s'han aplicat sobre el teixit no teixit mitjançant l'aplicació d'un lligam, en aquest cas s'ha estudiat l'ús de dos polímers naturals completament biodegradables, donada l'aplicació final. Els teixits no teixits han estat caracteritzats per diferent assajos, entre ells, l'evolució de la capacitat antimicrobiana i la resistència en condicions reals. Amb el desenvolupament d'aquesta investigació es pretén aprofitar les possibilitat que ofereix la microencapsulació, amb la finalitat d'obtindre un producte de valor agregat mantenint la sostenibilitat.Ferrándiz García, M. (2015). Encapsulación de aceites esenciales funcionales para su aplicación en agricultura [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/58990TESI

Application of antimicrobial microcapsules on agrotextiles

[EN] The aim of this work was to develop a functional biodegradable nonwoven with antimicrobial microcapsules maintaining the stability and biodegradability of the nonwoven for use in agriculture applications. The nonwoven was obtained using hemp fibers by Wetlaid technology. Microcapsules were prepared by co-extrusion/gelling method with alginate as shell and oregano oil as core material. The microcapsules were developed to protect and control release of oregano oil. Microcapsules were incorporated on the nonwoven by coating method using a natural polymer as a graft material. After incorporating microcapsules, the nonwoven was subjected to several tests in order to determinate the microcapsules fixation and their functionality. The nonwovens were characterized for their antimicrobial activity against different kinds of bacteria and fungi. Nonwoven loaded with microcapsules was found to show good antimicrobial activity in comparison with nonwoven that was not loaded with microcapsules.The authors thank IVACE (Institut Valencià de Competitivitat Empresarial, Spain) and FEDER (Fondo Europeo de Desarrollo Regional, Europe) for the financial support.Ferrándiz, M.; Capablanca, L.; Garcia-Sanoguera, D.; Bonet-Aracil, M. (2017). Application of antimicrobial microcapsules on agrotextiles. Journal of Agricultural Chemistry and Environment. 6(1):62-82. doi:10.4236/jacen.2017.61004S62826

Antimicrobial activity of metal cation-exchanged zeolites and their evaluation on injection-molded pieces of bio-based high-density polyethylene

[EN] In this study, three different natural types of unmodified zeolite (chabazite, mordenite, and faujasite) were initially characterized for their morphology, elemental composition, and antimicrobial activity against foodborne bacteria and fungi. The chabazite-type zeolite was selected due to its optimal morphology and lowest silicon to aluminum ratio (Si/Al). This was then solution exchanged with different combinations of silver (Ag+), copper (Cu2+), and zinc (Zn2+) ions to prepare single, binary, and ternary metal cation-modified zeolites. Antimicrobial results clearly indicated that Ag-based zeolites exhibited more antimicrobial activity than Cu- and Zn-based zeolites. Interestingly, the multi-ionic zeolite, that is, the ternary Ag-Cu-Zn-zeolite, was the most efficient antimicrobial sample in terms of the amount of added silver. In the last step, the obtained multi-ionic zeolite was, for the first time, incorporated at different weight amounts (1, 5, 10, and 15 wt%) into a bio-based high-density polyethylene (bio-HDPE) matrix by extrusion and shaped into pieces by injection molding. Novel sustainable polymer composite pieces with improved stiffness and hardness and high antimicrobial activity were obtained. These treated materials offer industrial relevance to control the growth of harmful microorganisms in hygiene applications related to the food industry.Spanish Ministry of Economy and Competitiveness, Grant/Award Number: Project MAT2014-59242-C2-1-R; Conselleria d'Educacio, Cultura i Esport - Generalitat Valenciana, Grant/Award Number: GV/2014/008Torres-Giner, S.; Torres, A.; Ferrándiz, M.; Fombuena, V.; Balart, R. (2017). Antimicrobial activity of metal cation-exchanged zeolites and their evaluation on injection-molded pieces of bio-based high-density polyethylene. Journal of Food Safety. 37(4). https://doi.org/10.1111/jfs.12348Se1234837

Polyamide fabric coated with a DHA-loaded chitosan hydrogel for a cosmeto-textile application

Cosmeto-textiles, which allow the administration of molecules when in contact with the skin, are increasingly being developed by cosmetic industries. We have designed an innovative approach for cosmeto-textile products, based on the impregnation of textile fibers with chitosan hydrogels, which have been cross-linked with genipin and loaded with dihydroxyacetone, which is an active component that induces sunless tanning. Dihydroxyacetone-loaded chitosan hydrogels have been prepared and characterized by means of cryogenic scanning electron microscopy (cryo-SEM). The images showed that genipin cross-linking decreases the mesh distance of hydrogels. The release of dihydroxyacetone from these cross-linked genipin chitosan hydrogels has been studied by a dialysis membrane method. These dihydroxyacetone-loaded chitosan hydrogels have been incorporated to polyamide textiles by a simple padding technique. The presence of dihydroxyacetone on these textiles has been detected by hyperspectral imaging on a dark field high resolution optical microscope. Finally, the performance of fabrics as cosmeto-textiles, with a tanning effect, has been evaluated by skin-colorimetry measured with an evaluation panel of 10 people. The results have demonstrated that dihydroxyacetone-loaded textiles produce a tanning effect on skin, and incorporation of dihydroxyacetone-loaded chitosan hydrogels into polyamide fabrics represents a friendly and appropriate strategy to obtain a cosmeto-textile with tanning effect

Development and Characterization of Weft-Knitted Fabrics of Naturally Occurring Polymer Fibers for Sustainable and Functional Textiles

[EN] This study focuses on the potential uses in textiles of fibers of soy protein (SP) and chitin, which are naturally occurring polymers that can be obtained from agricultural and food processing by-products and wastes. The as-received natural fibers were first subjected to a three-step manufacturing process to develop yarns that were, thereafter, converted into fabrics by weft knitting. Different characterizations in terms of physical properties and comfort parameters were carried out on the natural fibers and compared to waste derived fibers of coir and also conventional cotton and cotton-based fibers, which are widely used in the textile industry. The evaluation of the geometry and mechanical properties revealed that both SP and chitin fibers showed similar fineness and tenacity values than cotton, whereas coir did not achieve the expected properties to develop fabrics. In relation to the moisture content, it was found that the SP fibers outperformed the other natural fibers, which could successfully avoid variations in the mechanical performance of their fabrics as well as impair the growth of microorganisms. In addition, the antimicrobial activity of the natural fibers was assessed against different bacteria and fungi that are typically found on the skin. The obtained results indicated that the fibers of chitin and also SP, being the latter functionalized with biocides during the fiber-formation process, showed a high antimicrobial activity. In particular, reductions of up to 100% and 60% were attained for the bacteria and fungi strains, respectively. Finally, textile comfort was evaluated on the weft-knitted fabrics of the chitin and SP fibers by means of thermal and tactile tests. The comfort analysis indicated that the thermal resistance of both fabrics was similar to that of cotton, whereas their air permeability was higher, particularly for chitin due to its higher fineness, which makes these natural fibers very promising for summer clothes. Both the SP and chitin fabrics also presented relatively similar values of fullness and softness than the pure cotton fabric in terms of body feeling and richness. However, the cotton/polyester fabric was the only one that achieved a good range for uses in winter-autumn cloths. Therefore, the results of this work demonstrate that non-conventional chitin and SP fibers can be considered as potential candidates to replace cotton fibers in fabrics for the textile industry due to their high comfort and improved sustainability. Furthermore, these natural fibers can also serve to develop novel functional textiles with antimicrobial properties.This research work was funded by the Spanish Ministry of Science and Innovation (MICI) project number MAT2017-84909-C2-2-R.Ferrándiz, M.; Fages, E.; Rojas-Lema, SP.; Ivorra-Martinez, J.; Gomez-Caturla, J.; Torres-Giner, S. (2021). Development and Characterization of Weft-Knitted Fabrics of Naturally Occurring Polymer Fibers for Sustainable and Functional Textiles. Polymers. 13(4):1-17. https://doi.org/10.3390/polym13040665S11713

An enzymatic system for decolorization of wastewater dyes using immobilized CueO laccase-like multicopper oxidase on poly-3-hydroxybutyrate

The presence of synthetic dyes in wastewaters generated by the textile industry constitutes a serious environmental and health problem that urges the scientific community on an appropriate action. As a proof-of-concept, we have developed a novel approach to design enzymatic bioreactors with the ability to decolorize dye solutions through the immobilization of the bacterial CueO laccase-like multicopper oxidase from Escherichia coli on polyhydroxybutyrate (PHB) beads by making use of the BioF affinity tag. The decolorization efficiency of the system was characterized by a series of parameters, namely maximum enzyme adsorption capacity, pH profile, kinetic constants, substrate range, temperature and bioreactor recycling. Depending on the tested dye, immobilization increased the catalytic activity of CueO by up to 40-fold with respect to the soluble enzyme, reaching decolorization efficiencies of 45-90%. Our results indicate that oxidase bioreactors based on polyhydroxyalkanoates are a promising alternative for the treatment of coloured industrial wastewaters

Variation of cotton properties due to the application of sea fragance microcapsules

[EN] Cotton fabrics are used in multiple applications consequently, are susceptible to treatments for its functionalization. Microcapsules interest is increasing among the industry field as they allow to incorporate multiple functions to textiles. The finishing treatments that incorporate microcapsules contain in their formulations binding agents in order to increase their permanence on the textile. In this work, different concentrations of resin are tested in order to evaluate weather its application on industrial formulations with microcapsules influences the flexural rigidity on the cotton fabric. Considering that the application of the microcapsules is carried out in the final phase of the textile proces, it can modify the fabric appearenace. The possible color modification that is generated on three colors, red, yellow and blue at 2 0 /o on fiber weight has also been evaluated. The study shows that not only the resin influences the flexural rigidity of the tissue, but the presence of microcapsules also modifies this behavior. In addition, it is proven that the color variation is not significant to detect a perceptible change in tissue coloration. Flexural rigidity modification can be obsereved previusly to observe changes in color.[ES] Los tejidos de algodón se emplean en múltiples aplicaciones, y como tal son susceptibles de tratamientos para su funcionalización. Las microcápsulas son productos que han captado el interés de la industria por permitir incorporar múltiples funciones a los textiles. Los tratamientos de acabado que incorporan microcápsulas contienen en sus formulaciones agentes de ligado (resinas) con el fin de incrementar su permanencia sobre el textil. En este trabajo se ensayan diferentes concentraciones de resina con el fin de evaluar si la aplicación de ésta en las concentraciones utilizadas en formulaciones industriales con microcápsulas influye en la rigidez a la flexión del tejido de algodón. Dado que la aplicación de las microcápsulas se realiza en la fase final del procesado, también se ha evaluado la posible modificación de color que se genera sobre tres colores, rojo, amarillo y azul al 2% sobre peso de fibra. El estudio pone de manifiesto que no sólo la resina influye en la rigidez a la flexión del tejido sino que la presencia de microcápsulas también modifica el comportamiento. Además, queda probado que la variación de color no es significativa para detectar un cambio perceptible en la coloración del tejido. Los cambios en la rigidez a la flexión se manifiestan con anterioridad a que la variación de color sea perceptibleLos autores agradecen al IVACE (Institut Valencià de Competitivitat Empresarial, Spain) and FEDER (Fondo Europeo de Desarrollo Regional, Europe) por el soporte financiero aportado mediante el proyecto MICROTECH I y II así como por el proyecto AGROBIOTEX I y II.Bonet-Aracil, M.; Bou-Belda, E.; López-Narbón, A.; Ferrándiz-García, M.; Capablanca Francés, L. (2018). Modificación de las propiedades en los tejidos de algodón tratados con microcápsulas de esencia marina. DYNA: Ingeniería e Industria. 93(5):563-568. https://doi.org/10.6036/8670S56356893

Microencapsulation of essential oils by interfacial polimerization using polyurea as a wall material

[EN] An essential oil is the volatile lipophilic component extracted from plants. Microencapsulation systems protect the essential oil from degradation and evaporation, and, at the same time, allow a sustained release. This work analyses and characterizes the oregano and sage essential oil microcapsules prepared by interfacial polymerization technique, using polyurea as wall material. Several instrumental techniques are used: optical microscopy, size particle, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), Termo gravimetric analysis (TGA), spectrophotometry, antimicrobial test and chromatography. Results show that oregano and sage oil have antimicrobial properties, and their microencapsulation allows knowing that these properties remain inside the microcapsules.The authors thank IVACE (Institut Valencià de Competitivitat Empresarial, Spain) and FEDER (Fondo Europeo de Desarrollo Regional, Europe) for the financial support.Ferrándiz García, M.; Capablanca Francés, L.; Bou-Belda, E.; García Sanoguera, D.; Bonet Aracil, MA.; Bartolomé, L. (2015). Microencapsulation of essential oils by interfacial polimerization using polyurea as a wall material. Journal of Encapsulation and Adsorption Sciences. 5:165-177. doi:10.4236/jeas.2015.54014S165177

Removing of Direct Red 83:1 using α- and HP-α-CDs polymerized with epichlorohydrin: Kinetic and equilibrium studies

The adsorption properties of two cyclodextrin-epichlorohydrin polymers to remove Direct Red 83:1 textile dye from wastewater solutions was evaluated. Adsorption studies were performed in a batch reactor, and the efficiency of the polymers under different parametric values such as contact time, adsorbent dosage, initial dye concentration, pH of initial solution and temperature was followed by spectrophotometry. Both Langmuir and Freundlich equations were used to fit the equilibrium isotherms and the kinetic data were analyzed by the pseudo-first-order and pseudo-second-order models. Adsorption process follows a pseudo-second-order kinetic and was influenced by intraparticle diffusion model, dye concentration and contact time, reaching equilibrium within the first 30 min. Experimental data were better fitted to Freundlich isotherm model than to Langmuir and Temkin isotherms. Since about 93% of dye removal was achieved under optimized conditions, the α-cyclodextrin-epichlorohydrin polymer seems to be a useful device for removing Direct Red 83:1 from aqueous solutions and industrial effluents.Ciencias Ambientale

Adsorption Properties of β- and Hydroxypropyl-β-Cyclodextrins Cross-Linked with Epichlorohydrin in Aqueous Solution. A Sustainable Recycling Strategy in Textile Dyeing Process

β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) were used to prepare insoluble polymers using epichlorohydrin as a cross-linking agent and the azo dye Direct Red 83:1 was used as target adsorbate. The preliminary study related to adsorbent dosage, pH, agitation or dye concentration allowed us to select the best conditions to carry out the rest of experiments. The kinetics was evaluated by Elovich, pseudo first order, pseudo second order, and intra-particle diffusion models. The results indicated that the pseudo second order model presented the best fit to the experimental data, indicating that chemisorption is controlling the process. The results were also evaluated by Freundlich, Langmuir and Temkin isotherms. According to the determination coefficient (R2), Freunlich gave the best results, which indicates that the adsorption process is happening on heterogeneous surfaces. One interesting parameter obtained from Langmuir isotherm is qmax (maximum adsorption capacity). This value was six times higher when a β-CDs-EPI polymer was employed. The cross-linked polymers were fully characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA). Also, morphology and particle size distribution were both assessed. Under optimized conditions, the β-CDs-EPI polymer seems to be a useful device for removing Direct Red 83:1 (close 90%), from aqueous solutions and industrial effluents. Complementarily, non-adsorbed dye was photolyzed by a pulsed light driven advanced oxidation process. The proposed methodology is environmental and economically advantageous, considering the point of view of a sustainable recycling economy in the textile dyeing process.Ciencias Ambientale