• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 316
  • 36
  • 19
  • 10
  • 3
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 417
  • 417
  • 237
  • 216
  • 134
  • 97
  • 80
  • 65
  • 64
  • 63
  • 55
  • 48
  • 40
  • 39
  • 37
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

Morfo-anatomia e fitoquímica de Cymbopogon densiflorus (Steud.) Stapf e Cymbopogon nardus (L.) Rendle (Poaceae: Panicoideae) / Morphology, anatomy and phytochemistry of Cymbopogon densiflorus (Steud.) Stapf and Cymbopogon nardus (L.) Rendle

BARBOSA, Lília Cristina de Souza 28 September 2007 (has links)
Made available in DSpace on 2014-07-29T15:16:37Z (GMT). No. of bitstreams: 1 Dissertacao part 1 Lilia Cristina.pdf: 320067 bytes, checksum: 69f0c85320512078b0a799d535fe13a5 (MD5) Previous issue date: 2007-09-28 / The genus Cymbopogon Sprengel belong to the Poaceae family and it has 40 species distributed in Tropical and Subtropical Africa, Asia and Australia, although some species went introduced in America. Many species of this genus are cultivated for the extraction of essential oil, from their leaves, with large medicinal, food and industrial importance. The species in focus, Cymbopogon densiflorus (Steud.) Stapf and C. nardus (L.) Rendle are originated from Africa and Asia, respectively. This research had as objective, to broaden the knowledge about the species C. densiflorus and C. nardus, by the morphological and anatomy studies from leaves and culms, phytochemical analysis and essential oil analysis from the leaves. Anatomical studies have been of relevant importance to the pharmacognosy researches, mainly for the identification of many vegetal raw materials. Several times, these raw materials are known by the same popular name or then, they are commercialized with contaminated agents or with other parts of the specie. Through of anatomical analysis, it was checked commons characters, such as leaf lamina and sheath amphistomata, stomatas with guard cells dumbbell and subsidiary cells dome-shape, rares in adaxial surface and abundant in abaxial surface, predominated in intercostal zones. The adaxial and abaxial surfaces had long cells and short cells: cork and dumb-bell and cross-shaped silica cells, these last it is placed in costal zones; macro-hairs and micro-hairs abundant in abaxial surface. In the leaf lamina, bulliforms cells are presents in adaxial surface, they were alternated with fibers in the costal zones and the mesophyll is homogeneous with chlorenchyma radiated to the bundle sheaths and arm cells with walls invaginated that they determined the intervenal distance by one or three cells, characterized Kranz anatomy. Bundle sheaths collateral, of 1st, 2nd and 3rd orders with single vascular bundle sheaths. The cap region is constituted by sclerenchyma and the epidermis has silica cells. However, both species had different anatomical features, as the form of midrib, in the leaf laminas; C. densiflorus showed colourless parenchyma cells in the mesophyll of leaf sheaths, that they do not exist in C. nardus. In the culms, numbers of metaxylem vessels in the each side of protoxylem vessels in vascular bundles: 1, in C. densiflorus, 2 and 3, in C. nardus; and the presence of sclerenchyma cylinder and fistula in C. nardus, absent characters in C. densiflorus. Moreover, in C. densiflorus, while C. nardus showed these characters. The preliminary phytochemistry analysis C. densiflorus and C. nardus leaves evidencied flavonoids, saponins, coumarins and traces of cardioactive glycosides. In the essential oil analysis, C. densiflorus leaves showed trans-p-mentha-1(7),8-dien-2-ol, trans-p-mentha-2-8-dien-1-ol, cis-carveol and cis-p-mentha-2-8-dien-1-ol as majority constituents; while C. nardus leaves had geraniol, citronellol and citronellal. The anatomical characters observed can be important to the taxonomic determinations of species studied, in the genus. Through the results found, it verifies the phytotherapics potential of both species. Future researches in isolation and purify of the secondary metabolites, pharmacologics and toxicologics analysis of extracts and of the essential oil, it will be important to assure the therapeutic efficiency of these. / O gênero Cymbopogon Sprengel pertence à família Poaceae e compreende 40 espécies, distribuídas pela África Tropical e Subtropical, Ásia e Austrália, embora algumas foram introduzidas na América. Diversas espécies deste gênero são cultivadas para a extração de óleos essenciais, a partir de suas folhas, sendo então de grande importância medicinal, alimentar e industrial. As espécies em estudo Cymbopogon densiflorus (Steud.) Stapf e C. nardus (L.) Rendle, são originárias da África e Ásia, respectivamente. Esta pesquisa teve por objetivo, ampliar o conhecimento sobre as espécies C. densiflorus e C. nardus, por meio do estudo morfo-anatômico das folhas e colmo, prospecção fitoquímica e análise dos óleos essenciais das folhas. Estudos anatômicos têm sido de relevante importância para pesquisas farmacognósticas; principalmente para a identificação de diversas matérias-prima vegetal, que muitas vezes são conhecidas pelo mesmo nome popular ou então, comercializadas com contaminantes ou de outras partes da mesma espécie. Por meio das análises anatômicas verificaram-se caracteres comuns entre ambas as espécies, tais como lâminas e bainhas foliares anfiestomáticas, estômatos com células-guarda halteriformes e células subsidiárias em forma de cúpula, raros na face adaxial e abundantes na face abaxial predominando nas regiões intercostais. As faces adaxial e abaxial apresentam células longas e células curtas: suberosas e silicificadas halteriforme e cruciforme, sendo as últimas localizadas nas regiões costais; macrotricomas e microtricomas predominam na face abaxial. Nas lâminas foliares, as células buliformes estão presentes na face adaxial da epiderme, intercaladas por fibras na região costal e o mesofilo é homogêneo disposto radialmente aos feixes vasculares, com distância intervenal de uma a três células, caracterizando anatomia Kranz. Os feixes vasculares colaterais, de 1ª, 2ª e 3ª ordens com bainha de feixe única. A região do bordo é formada por fibras e a epiderme apresenta células silicificadas. Entretanto, ocorrem características anatômicas distintas entre as duas espécies, como formato da nervura central, nas lâminas foliares; C. densiflorus apresenta células parenquimáticas incolores, na bainha foliar, que estão ausentes em C. nardus e o número de elementos de metaxilema em cada lado dos elementos de protoxilema: 1, em C. densiflorus e 2 a 3, em C. nardus e presença de cilindro esclerenquimático e medula fistulosa em C. nardus, caracteres ausentes em C. densiflorus. A análise fitoquímica preliminar das folhas de C. densiflorus e C. nardus evidenciou flavonóides, saponinas, cumarinas e traços de heterosídeos cardioativos. Na análise dos óleos essenciais, as folhas de C. densiflorus apresentaram trans-p-menta-1(7),8-dien-2-ol, trans-p-menta-2-8-dien-1-ol, cis-carveol e cis-p-menta-2-8-dien-1-ol, como constituintes majoritários; enquanto que em C. nardus foram geraniol, citronelol e citronelal. Os caracteres anatômicos observados podem ser importantes para as determinações taxonômicas das espécies estudadas. Por meio dos resultados encontrados, verifica-se o potencial fitoterápico de ambas as espécies. Futuras pesquisas em isolamento e purificação dos metabólitos secundários, análises farmacológicas e toxicológicas dos extratos e dos óleos essenciais, serão importantes para assegurar a eficácia terapêutica destas.
412

Caractérisations chimiques et biologiques d’extraits de plantes aromatiques oubliées de Midi-Pyrénées / Chemical and biological characterizations of extracts of medieval aromatic plants from Midi-Pyrenees

El Kalamouni, Chaker 13 December 2010 (has links)
Les plantes aromatiques font parties des richesses naturelles du patrimoine de la région Midi-Pyrénées mais apparaissent cependant de moins en moins valorisées. Dans le cadre de la recherche de nouveaux aromatisants naturels de type WONF, nous avons choisi d'adopter la voie de valorisation des plantes aromatiques médiévales de cette région car elles ont toujours fait l'objet de cueillette à l'état sauvage sans jamais être cultivées. Dans une première étape, une étude bibliographique a été réalisée, à partir d'anciens ouvrages botaniques et de bases de données scientifiques, afin d'identifier les plantes régionales traditionnellement utilisées par nos ancêtres pour leurs activités aromatisantes, culinaires ou médicinales. Nous avons sélectionné cinq plantes aromatiques : Achillea millefolium, Calamintha grandiflora, Tanacetum balsamita, Myrrhis odorata et Monarda didyma. Dans une deuxième étape, des études physico-chimiques, sensorielles et biologiques des fractions volatiles et non volatiles, obtenues après extractions des plantes médiévales sélectionnées, ont été réalisées pour juger de leurs activités aromatiques, antioxydantes et antibactériennes ainsi que de leur intérêt dans le cadre de nouvelles réglementations européennes. Les résultats de ces travaux montrent des activités odorantes, antioxydantes et antibactériennes significatives pour l'ensemble des plantes sélectionnées. Dans une troisième étape, du fait de la rareté du végétal étudié, nous nous sommes intéressés à deux voies analytiques d'évaluation rapide de la composition de l'huile essentielle native de ces plantes aromatiques ; premièrement au moyen d'un échantillonnage classique couplé à un détecteur à forte sensibilité comme la chromatographie bidimensionnelle et deuxièmement par un échantillonnage spécifique couplé à un détecteur classique pour lequel nous avons développé un appareillage novateur dénommé "Crushing Finger Device" (CFD). Ce dernier permet de mimer instrumentalement l'écrasement de la feuille entre les doigts et de piéger les composés volatils odorants émis en vue de leur analyse chromatographique ultérieure. Enfin, pour une application pré-industrielle, afin d'élargir le champ d'application de ces plantes aromatiques, des études d'infusion des plantes et d'aromatisation des huiles végétales par les huiles essentielles ont été mises en place. Durant le processus d'aromatisation de l'huile végétale, les volatils émis par la plante ou par l'huile essentielle donnent un goût et une saveur spécifique tout en délivrant une activité biologique notable. / Midi-Pyrenees region has a rich and unvalorized wild vegetal heritage, especially for aromatic plants. In the framework of the search for new natural flavorings e.g. WONF, we chose to adopt the way of valorization of the medieval aromatic plants of this region, because they have been always picked in a wild state without being ever grown. In a first step, a global bibliographical survey study based on historical books, library archived documents and computerized data banks, was made in order to identify regional plants which were used by our ancestors for their odorous, culinary or medicinal activities. We selected five aromatic plants, e.g. Achillea millefolium, Calamintha grandiflora, Tanacetum balsamita, Myrrhis odorata and Monarda didyma. In a second step, physico-chemical, sensory and biological studies of volatiles and non volatiles fractions, obtained by extractions of the selected medieval plants were carried out, to judge their aromatic, antioxidant and antibacterial activities and their interest within the framework of new european regulations. Theses results show a significant odorous, antioxidant and antimicrobial activities for all selected plants. In a third step, such plants were rare or their harvesting problematic, inducing a limited sampling. We decided to investigate two strategic approaches to perform a rapid evaluation of native essential oil, based either on a classic sampling with a specific/ultra sensitive detection such as Comprehensive GC, nor the use of a specific/high effective sampling system with a classic detection. This last methodology was based on a self designed apparatus “Crushing Finger Device” (CFD), allowing to copy the crushing of leaves between fingers and to trap the volatiles emitted to their later chromatographic analysis. Finally, in the aim to expand the use of aromatic plants, also to enlarge the assortment of oil products, a pre-industrial application were carried out. Infusion of plants and flavoring of vegetable oil by essential oil were studied. During processing of aromatized vegetable oil, volatiles from added aromatic plants or essential oil migrate to oil to give a specific aroma and a significant biological activity. Plantes aromatiques oubliées, Huile essentielle, Antioxydant, Antibactérien, Simulateur de froissement, Composés d’arômes, Achillea millefolium, Calamintha grandiflora, Tanacetum balsamita, Myrrhis odorata, Monarda didyma.
413

Hemijski sastav, biološke i funkcionalne karakteristike novih proizvoda od zove / Chemical composition, biological and functional characteristics of new elderberry products

Vujanović Milena 14 December 2020 (has links)
<p>Glavni cilj ove doktorske disertacije je određivanje hemijskog sastava, biolo&scaron;kih i funkcionalnih karakteristika novih proizvoda od zove. Dobijanje proizvoda na bazi zove zasniva se na primeni tradicionalnih i savremenih tehnolo&scaron;kih procesa proizvodnje. Iskori&scaron;ćenje prirodnog potencijala zove započeto je primenom tradicionalne i savremene (liofilizacija) tehnike su&scaron;enja. U cilju dobijanja visoko-vrednih ekstrakata ploda i cveta zove primenjene su tradicionalna (maceracija) i savremene (ultrazvučna i mikrotalasna) ekstrakcione tehnike sa dva ekstragensa (50% etanol i voda). Dobijanje matičnog soka od plodova zove podrazumevalo je primenu tradicionalnog načina ceđenja, dok je vino od plodova zove dobijeno po standardnom postupku proizvodnje vina. Vino je izloženo različitim temperaturnim tretmanima u različitom vremenskom periodu (60 &deg;C u toku 5 minuta, 60 &deg;C u toku 10 minuta, 70 &deg;C u toku 5 minuta i bez toplotnog tretmana) u cilju evaluacije biolo&scaron;ke aktivnosti dobijenog proizvoda. Etarsko ulje ploda i cveta zove je dobijeno hidrodestilacijom. Ispitivanje efikasnosti primenjenih tehnolo&scaron;kih postupaka su&scaron;enja i ekstrakcije je zasnovano na određivanju biolo&scaron;kih i funkcionalnih karakteristika dobijenih ekstrakata ploda i cveta zove. U ispitivanim ekstraktima ploda i cveta zove dominantne fenolne kiseline su hlorogenska i protokatehinska kiselina, a rutin i kvercetin-3-O-heksozid su dominantna flavonoidna jedinjenja. Biolo&scaron;ke i funkcionalne karakteristike su ispitane primenom različitih in vitro antioksidativnih, neuroprotektivnih, antitirozinaznih i antidijabetogenih testova. Primenom liofilizacije kao savremene tehnike su&scaron;enja i mikrotalasne ekstrakcije kao savremene ekstrakcione tehnike povećava se biopotencijal ispitivanih ekstrakata. Matični sok od plodova zove kao potencijalno novi funkcionalni proizvod je analiziran u cilju definisanja hemijskog, fitohemijskog i nutritivnog sastava, biolo&scaron;kog potencijala i senzorskih karakteristika. Ispitivanja dobijenog vina su bila usmerena na utvrđivanje optimalnih uslova za proizvodnju voćnog vina. Definisanjem hemijskog i fitohemijskog sastava i evaluacijom biopotencijala vina određen je optimalan temperaturni profil za dobijanje jednog od novih funkcionalnih proizvoda. Na osnovu utvrđenog hemijskog sastava etarsko ulje ploda i cveta zove se pokazalo kao potencijalno novi prirodni agens za održavanje svežine i produženja roka trajanja prehrambenih proizvoda. Zova je nesumnjivo samonikla biljna vrsta koja u budućnosti osnovano može biti polazna sirovina za kreiranje i dobijanje novih prehrmabenih proizvoda na domaćem i inostranom trži&scaron;tu.</p> / <p>The main goal of this doctoral dissertation is to determine the chemical composition, biological and functional characteristics of new elderberry products. Elderberry products were obtained via traditional and modern technological processes. The exploitation of the natural potential of the elderberry started with the application of traditional and modern (lyophilization) drying techniques. To obtain high-value extracts of fruits and flowers, traditional (maceration) and modern (ultrasonic and microwave) extraction techniques with two solvents (50% ethanol and water) were applied. Obtaining the juice from the elderberry fruits implied the application of the traditional cold pressing method, whereas wine from the elderberry fruits was obtained in accordance with the standard procedure of wine production. The wine was exposed to different temperature treatments in different periods (60&deg;C for 5 minutes, 60&deg;C for 10 minutes, 70&deg;C for 5 minutes and without heat treatment) to evaluate the biological activity of the product. The essential oil of the fruit and flower was obtained by hydrodistillation. The examination of the efficiency of the applied technological procedures of drying and extraction is based on observing the biological and functional characteristics of the obtained extracts of the said fruits and flowers. In the examined fruit and flower extracts, the dominant phenolic acids are chlorogenic and protocatechuic acid, while rutin and quercetin-3-O-hexoside are the dominant flavonoid compounds. Biological and functional characteristics were examined using various in vitro antioxidant, neuroprotective, antityrosinase, and antidiabetic tests. The application of lyophilization and microwave extraction (as modern drying and extraction techniques) increased the biopotential of the analyzed extracts. Elderberry juice, a potentially new functional product, was analyzed to define the chemical, phytochemical and nutritional composition, biological potential, and sensory characteristics. The wine was tested in order to determine the optimal conditions for the production of fruit wine. By defining the chemical and phytochemical composition and evaluating the biopotential of wine, the optimal temperature profile for obtaining one of the new functional products was determined. Based on the obtained chemical composition, it is determined that the essential oil of fruits and flowers is a potentially new natural agent for maintaining freshness and extending the shelf life of food products. Without a doubt, elderberry is a wild plant species that could be used in the future as the starting material for creating and obtaining new food products on the domestic and foreign markets.</p>
414

Síntesis, caracterización y aplicaciones de microcápsulas de aceite esencial de naranja (Citrus sinensis) en tejidos 100 % algodón / Síntese, caracterização e aplicações de microcápsulas de óleo essencial de laranja (Citrus sinensis) em tecidos 100 % algodão

Soares Rossi, Wagner 11 April 2022 (has links)
[ES] La tecnología de microencapsulación se ha utilizado en áreas como farmacología, medicina, ingeniería y diseño. Centrado en el área de la ingeniería, más específicamente, la selección de materiales y el desarrollo de productos, el carácter simbólico, perceptivo y funcional se puede combinar para el diseño de productos innovadores. Mediante la tecnología de microencapsulación se combinan una amplia gama de materiales de núcleo y membrana, más específicamente en la área textil, la aplicación de microcápsulas puede proporcionar el desarrollo de tejidos y materiales funcionales con propiedades específicas. En este contexto, este trabajo se propone verificar las condiciones y analizar la síntesis de microcápsulas de aceite esencial de naranja (Citrus sinensis) y estudiar su comportamiento cuando se aplica a tejidos de algodón. Para la síntesis de microcápsulas de membrana polimérica de melamina-formaldehído con núcleo de aceite esencial de naranja (Citrus sinensis) se utilizó el método de polimerización in situ. El aceite esencial de naranja se caracterizó por cromatografía de gases, espectroscopia infrarroja por transformada de Fourier, termogravimetría, las microcápsulas sintetizadas se caracterizaron por espectroscopia infrarroja por transformada de Fourier, termogravimetría, microscopía electrónica de barrido y haz de iones enfocado. Las microcápsulas poliméricas con núcleo de aceite esencial de naranja sintetizadas se aplicaron al tejido algodón mediante tres métodos diferentes (impregnación, pulverización y estampación). Después de la aplicación sobre el tejido de algodón, se realizón prueba de frote, pruebas de lavado y prueba de actividad antibacteriana en laboratorio para estudiar el comportamiento de las microcápsulas sobre el sustrato. La caracterización de las muestras de tejido con las microcápsulas aplicadas, antes y después de las pruebas de durabilidad, se realizó mediante microscopía electrónica de barrido y espectroscopía infrarroja por transformada de Fourier. Al finalizar se sistematizaron los procedimientos, condiciones y parámetros para la polimerización in situ así como la aplicación de microcápsulas poliméricas con núcleo de aceite esencial de naranja (Citrus sinensis) en tejido 100 % algodón, avanzando en el estudio de la selección de materiales para aplicación en textiles que se puede utilizar para el desarrollo de productos innovadores. Los resultados mostraron que se produjo la microencapsulación del aceite esencial de naranja volátil y que las microcápsulas aplicadas al tejido de algodón presentan actividad antibacteriana y resistien quince ciclos de lavado utilizando la norma ISO 105 C06: 2010. / [CA] La tecnologia de la microencaspulació s'utilitza en àrees com farmacologia, medicina, enginyeria i disseny. Centrat en l'àrea de l'enginyeria específicament, la selecció dels materials i el desenvolupament de productes de caràcter simbólic, perceptiu i funcional es pot combinar per al disseny de productes innovadors. Mitjançant la tecnologia de la microencapsulació es combinen una àmplia gamma de materials de nucli i membrana, més específicament en l'àrea tèxtil, l'aplicació de microcàpsules pot proporcionar el desenvolupament de teixits i materials funcionals amb propietats específiques. En aquest context, aquest treball es proposa verificar les condicions i analitzar la síntesi de microcàpsules d'oli essencial de taronja (Citrus sinensis) i estudiar el seu comportament quan s'aplica als teixits de cotó. Per a la síntesi de microcápsules de membrana polimèrica de melanina-formalheid amb nucli d'oli essencial de taronja (Citrus sinensis) s'ha utilitzat el mètode de polimeritzacio in situ. L'oli essencial de taronja es va caracteritzar per cromatografia de gasos, espectroscòpia infraroja per transformada de Fourier, termogravimetria, les microcàpsules sintetitzades es caracteritzaven per espectroscopia infraroja per transformada de Fourier, termogravimetria, microscòpia electrònica d'escombrat i feix d'ions enfocat. Les microcàpsules polimèriques amb nucli d'oli essencial de taronja sintetitzades s'han aplicat al teixit de cotó mitjançant tres mètodes diferents (impregnació, pulverització i estampat). Després de l'aplicació sobre el teixit de cotó, s'ha realitzat prova de trot, prova de llavat i prova de activitat antibacteriana en laboratori per a estudiar el comportament de les microcàpsules sobre el sustrat. La caracterització de les mostres de teixit amb microcàpsules aplicades, abans i després de les proves de durabilitat, s'ha realitzat mitjançat microscòpia electrònica d'escombrat i espectroescòpia infraroja per transformada de Fourier. Al finalitzar la sistematització dels procediments, condicions i paràmetres per a la polimerització in situ així com l'aplicació de microcàpsules polimèriques amb nucli d'oli essencial de taronja (Citrus Sinensis) en teixit de cotó 100%, avançat en l'estudi de la selecció de materials per a l'aplicació en tèxtil que es puga utilitzar en el desenvolupament de productes innovadors. Els resultats han demostrat que s'ha produït la microencapsulació del oli essencial de taronja volàtil i que les microcàpsules aplicades al teixit de cotó presenten activitat antibacteriana han resistit quinze cicles de llavat utilitzant la normativa ISO 105 C06:2010. / [EN] Microencapsulation technology has been used in areas such as pharmacology, medicine, engineering and design. Focused on the engineering area, more specifically, material selection and product development, the symbolic, perceptive and functional character can be combined for the design of innovative products. Through microencapsulation technology, a wide range of core and membrane materials are combined, more specifically in the textile area, the application of microcapsules can provide the development of fabrics and functional materials with specific properties. In this context, this work proposes to verify the conditions and analyze the synthesis of microcapsules of orange essential oil (Citrus sinensis) and study their behavior when applied to cotton fabric. For the microcapsules synthesis of melamine-formaldehyde polymeric membrane with orange essential oil core (Citrus sinensis), the in situ polymerization method was used. The orange essential oil was characterized by gas chromatography, Fourier transform infrared spectroscopy, thermogravimetric, the synthesized microcapsules were characterized by Fourier transform infrared spectroscopy, thermogravimetric, scanning electron microscopy and focused ion beam. The polymeric microcapsules with an orange essential oil core synthesized were applied to cotton fabric by three different methods (impregnation, spraying and screen printing). After application on the cotton fabric, friction tests, washing tests and antibacterial activity tests were performed in the laboratory to study the behavior of microcapsules on the substrate. The characterization of fabric samples with the applied microcapsules, before and after the durability tests, was performed by scanning electron microscopy and infrared spectroscopy by Fourier transform. At the end, the procedures, conditions and parameters for in situ polymerization as well as the application of polymeric microcapsules with an orange essential oil core (Citrus sinensis) in 100 % cotton fabric were systematized, advancing the study of the selection of materials for application in textiles that can be used for the development of innovative products. The results showed that microencapsulation of the volatile orange essential oil occurred and that the microcapsules applied to the cotton fabric showed antibacterial activity and resisted fifteen washing cycles using the ISO 105 C06: 2010. / Soares Rossi, W. (2022). Síntesis, caracterización y aplicaciones de microcápsulas de aceite esencial de naranja (Citrus sinensis) en tejidos 100 % algodón [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182096
415

Могућност гајења иђирота (Acorus calamus L.) у циљу смањења притиска на природну популацију / Mogućnost gajenja iđirota (Acorus calamus L.) u cilju smanjenja pritiska na prirodnu populaciju / Possibility of cultivating sweet flag (Acorus calamus L.) in the purpose of lowering the pressure on the natural population

Škobić Slađana 29 September 2016 (has links)
<p>&nbsp;Acorus calamus L. је вишегодишња зељаста биљка влажних подручја, чија су лековита својства одавно позната. Дрогу иђирота чини ризом који се употребљава као чај, прах, сок, гел, уље или крема. Због прекомерне експлоатације и високог степена угрожености ове дивље лековите биљне врсте у Србији је уведена забрана његовог сакупљања из природе. Да би се задовољила повећана потражња од стране индустрија које га користе, гајење иђирота се намеће као једно од најпрагматичнијих решења. За потребе утврђивање начина гајења, прво се приступило истраживању услова успевања и варирање својстава иђирота са пет локалитета природних станишта: Обедска бара, Делиблатска пешчара, Засавица, Раковац и Дубовац. Потом је заснован двогодишњи пољски оглед на ком је испитиван утицај примене основних агротехничких мера, односно густине садње и ђубрења азотом, на својства биљака. Оглед је постављен 2013. године, на подручју засеока Ћумуране у насељу Рипањ. Код биљка са природних станишта и са огледног поља праћена су следећа својства: висина биљака, дужина ризома, број и дужина бочних грана на ризому, број пупољака на ризому и бочним гранама, број нодуса на ризому и бочним гранама, проценат суве материје ризома, маса свежег и сувог ризома, однос масе свежег и сувог ризома. Код гајених биљака праћен је и принос свежег и сувог ризома. Код свих узорака иђирота испитиван је садржај и састав етарског уља из ризома. Идентификоване су, такође, најзаступљеније компоненте и утврђен је садржаја &beta;-азарона. За утврђивање нивоа плоидије популација из Србије рађено је пребројавање хромозома. Испитивањем биљака са природних станишта, констатовано је да на већину њихових морфолошких одлика, локалитет није имао утицаја. Утицај локалитета испољен је само на: број нодуса на ризому (највећи је био у Дубовцу - 58 а најмањи на Обедској бари - 15), проценат суве материје (највећи је био у Раковцу - 50,2%, а најмањи на Делиблатској пешчари - 37,9%) и однос масе свежег и сувог ризома (највећи је на Делиблатској пешчари - 2,64, а најмањи у Раковцу - 1,90). У пољском огледу добијени су следећи резултати: висина биљака је била највећа при најмањој густини усева (35000 биљака/ha) и најмањој дози азота (60 kg/ha) дужина ризома, као и број и дужина њихових бочних грана су највећи при средњој густини садње (48000 биљака/ha) и најмањој дози азота; број пупољака на ризому има највећу вредност при најмањој густини садње и најмањој дози азота. Број пупољака прве бочне гране је био највећи на највећој густини садње (62000 биљака/ha) и при најмањој дози азота, а број нодуса на ризому није зависио од густине садње, као ни од доза ђубрења. Највећа маса свежег и сувог ризома остварена је при средњој густини садње (48000 биљака/ha) и најмањој (62000 биљака/ha) дози азота, док је проценат суве материје био највећи при највећој густини и најмањој дози азота (60 kg/ha). На однос масе свежег и сувог ризома утицај нису имали ни ђубрење ни густина</p><p>садње усева, док су приноси свежег и сувог ризома били највећи на највећој густини садње и при најмањој дози азота. Садржај етарског уља иђирота из природе није показао значајна одступања између локалитета. Садржај етарског уља ризома гајеног иђирота опадао је са порастом густине садње, док различите дозе азота нису утицале на ову особину. Максимална концентрација &beta;-азарона у етарском уљу иђирота са природног станишта била је 17,07 % (локалитет Раковац), док је највећи садржај &beta;-азарона код гајеног иђирота био 21,41 %. Повећана концентрација &beta;- азарона се објашњава интензивнијим метаболизмом азота, због повећане количине из ђубрива. обијени резултати потврђују да је концентрација &beta;-азарона у етарском уљу ризома иђирота слична резултатима из других земаља Европе. Бројањем хромозома утврђено је да иђирот припада триплоидном, европском варијетету Аcоrus cаlаmus vаr. cаlаmus.</p> / <p>&nbsp;Acorus calamus L. je višegodišnja zeljasta biljka vlažnih područja, čija su lekovita svojstva odavno poznata. Drogu iđirota čini rizom koji se upotrebljava kao čaj, prah, sok, gel, ulje ili krema. Zbog prekomerne eksploatacije i visokog stepena ugroženosti ove divlje lekovite biljne vrste u Srbiji je uvedena zabrana njegovog sakupljanja iz prirode. Da bi se zadovoljila povećana potražnja od strane industrija koje ga koriste, gajenje iđirota se nameće kao jedno od najpragmatičnijih rešenja. Za potrebe utvrđivanje načina gajenja, prvo se pristupilo istraživanju uslova uspevanja i variranje svojstava iđirota sa pet lokaliteta prirodnih staništa: Obedska bara, Deliblatska peščara, Zasavica, Rakovac i Dubovac. Potom je zasnovan dvogodišnji poljski ogled na kom je ispitivan uticaj primene osnovnih agrotehničkih mera, odnosno gustine sadnje i đubrenja azotom, na svojstva biljaka. Ogled je postavljen 2013. godine, na području zaseoka Ćumurane u naselju Ripanj. Kod biljka sa prirodnih staništa i sa oglednog polja praćena su sledeća svojstva: visina biljaka, dužina rizoma, broj i dužina bočnih grana na rizomu, broj pupoljaka na rizomu i bočnim granama, broj nodusa na rizomu i bočnim granama, procenat suve materije rizoma, masa svežeg i suvog rizoma, odnos mase svežeg i suvog rizoma. Kod gajenih biljaka praćen je i prinos svežeg i suvog rizoma. Kod svih uzoraka iđirota ispitivan je sadržaj i sastav etarskog ulja iz rizoma. Identifikovane su, takođe, najzastupljenije komponente i utvrđen je sadržaja &beta;-azarona. Za utvrđivanje nivoa ploidije populacija iz Srbije rađeno je prebrojavanje hromozoma. Ispitivanjem biljaka sa prirodnih staništa, konstatovano je da na većinu njihovih morfoloških odlika, lokalitet nije imao uticaja. Uticaj lokaliteta ispoljen je samo na: broj nodusa na rizomu (najveći je bio u Dubovcu - 58 a najmanji na Obedskoj bari - 15), procenat suve materije (najveći je bio u Rakovcu - 50,2%, a najmanji na Deliblatskoj peščari - 37,9%) i odnos mase svežeg i suvog rizoma (najveći je na Deliblatskoj peščari - 2,64, a najmanji u Rakovcu - 1,90). U poljskom ogledu dobijeni su sledeći rezultati: visina biljaka je bila najveća pri najmanjoj gustini useva (35000 biljaka/ha) i najmanjoj dozi azota (60 kg/ha) dužina rizoma, kao i broj i dužina njihovih bočnih grana su najveći pri srednjoj gustini sadnje (48000 biljaka/ha) i najmanjoj dozi azota; broj pupoljaka na rizomu ima najveću vrednost pri najmanjoj gustini sadnje i najmanjoj dozi azota. Broj pupoljaka prve bočne grane je bio najveći na najvećoj gustini sadnje (62000 biljaka/ha) i pri najmanjoj dozi azota, a broj nodusa na rizomu nije zavisio od gustine sadnje, kao ni od doza đubrenja. Najveća masa svežeg i suvog rizoma ostvarena je pri srednjoj gustini sadnje (48000 biljaka/ha) i najmanjoj (62000 biljaka/ha) dozi azota, dok je procenat suve materije bio najveći pri najvećoj gustini i najmanjoj dozi azota (60 kg/ha). Na odnos mase svežeg i suvog rizoma uticaj nisu imali ni đubrenje ni gustina</p><p>sadnje useva, dok su prinosi svežeg i suvog rizoma bili najveći na najvećoj gustini sadnje i pri najmanjoj dozi azota. Sadržaj etarskog ulja iđirota iz prirode nije pokazao značajna odstupanja između lokaliteta. Sadržaj etarskog ulja rizoma gajenog iđirota opadao je sa porastom gustine sadnje, dok različite doze azota nisu uticale na ovu osobinu. Maksimalna koncentracija &beta;-azarona u etarskom ulju iđirota sa prirodnog staništa bila je 17,07 % (lokalitet Rakovac), dok je najveći sadržaj &beta;-azarona kod gajenog iđirota bio 21,41 %. Povećana koncentracija &beta;- azarona se objašnjava intenzivnijim metabolizmom azota, zbog povećane količine iz đubriva. obijeni rezultati potvrđuju da je koncentracija &beta;-azarona u etarskom ulju rizoma iđirota slična rezultatima iz drugih zemalja Evrope. Brojanjem hromozoma utvrđeno je da iđirot pripada triploidnom, evropskom varijetetu Acorus calamus var. calamus.</p> / <p>&nbsp;&nbsp;Acorus calamus L. is a perennial herbaceous plant found in wet areas, whose medicinal properties have been long known. The drug of sweet flag is made from the rhizome which is used as tea, powder, juice, gel, oil or cream. Because of overexploitation and the high degree of endangerment of this wild medicinal plant species in Serbia collecting was banned. In order to meet the increased demand for this plant by industries that use it, cultivation of sweet flag is emerging as one of the most pragmatic solutions. For the purpose of determining the method for plant growth, the first approach was studying the growing conditions and the variation of properties of sweet flag from five natural habitats: Obedska pond, Deliblato Sands, Zasavica, Rakovac and Dubovac.After that a two-year field experiment was designed in which the effect of application of basic agrotechnical measures, i.e., different planting density and doses of nitrogen fertilization on the plants, was studied. The experiment was set up in 2013, in the area of the hamlet Ćumurana in the settlement Ripanj. In plants from natural habitats and the experiment, the following properties were measured: the height of the plants, the length of the rhizome, the number and length of lateral branches on the rhizome, the number of buds on the rhizome and lateral branches, the number of leaf scars on the rhizome and lateral branches, the percentage of dry matter of the rhizome, the mass of the fresh and the dry rhizome, the ratio of mass between the fresh and the dry rhizome. In the experiment with cultivated plants, the yield of the fresh and the dry rhizome was also measured. For all samples of sweet flag, the content and composition of the essential oil from the rhizome was measured. Also, the main components were identified and the content of the &beta;-asarone was determined. For the purposes of identifying the ploidy, i.e., which varieties the sweet flag from Serbia belongs to, counting of chromosomes was done. By examining plants from natural habitats, it was noted that the site had no influence on the majority of morphological features of plants. The impact of the sites was manifested only in the number of leaf scars (the largest number was in Dubovac-58,0 and the smallest number was in Obedska pond-15,0), percentage of dry matter (the largest percentage was in Rakovac-50.2% and the smallest percentage was in Deliblato Sands-37,9 %) and the ratio of mass between a fresh and a dry rhizome (the largest ratio was in Deliblato Sands-2,6 and the smallest ratio was in Rakovac-2,2). In the field experiment, the following results were obtained: the height of the plants is the largest at the lowest planting density (35000 plants/ha) and lowest nitrogen dosage (60 kg/ha), the length of the rhizome, as well as number and length of lateral branches of the rhizome are largest at medium planting density (48000 plants/ha) and the lowest dosage of nitrogen (60 kg/ha), the number of buds on the rhizome has the highest value at the lowest planting density (35000 plants/ha) and the lowest dosage of nitrogen (60 kg/ha). The number of buds on the first lateral branch was largest at the largest planting density (62000 plants/ha) and the lowest dosage of nitrog (60 kg/ha) , and the number of leaf scars on the rhizome does</p><p>not depend on the planting dosage or the dosage of fertilizing. The largest mass of the fresh and the dry rhizome is accomplished at medium planting density and the lowest dosage of nitrogen, while the percentage of dry matter was largest at the largest density and the lowest dosage of nitrogen. The fertilization and the crop density had no effect on the ratio of mass between the fresh and the dry rhizome, while the yields of the fresh and the dry rhizome were largest at the largest planting density and the lowest dosage of nitrogen. The content of essential oils of natural sweet flag showed no significant discrepancies between the sites. The content of essential oil of cultivated sweet flag rhizomes declined with the increase of planting density, while different nitrogen doses had no effect on this property. The maximum concentration of &beta;-asarones in the essential oil of natural sweet flag was 17,07 % (Rakovac), while the largest content of &beta;-asarones in cultivated sweet flag was 21,41 %. The larger concentration of &beta;-asarones is explained through increased nitrogen metabolism, because of increased amounts of fertilizer. The results confirm that the concentration of &beta;-asarone in the essential oil of sweet flag rhizomes is similar to the concentration of essential oil of sweet flag rhizomes from Europe. By counting the chromosomes it is established that sweet flag belongs to the triploid, European variety of Аcоrus cаlаmus vаr. cаlаmus.</p>
416

Caractérisations chimiques et biologiques d’extraits de plantes aromatiques et médicinales oubliées ou sous-utilisées de Midi-Pyrénées (France) et de Chongqing (Chine) / Chemical and biological characterisation of extracts from forgotten or underutilised medicinal and aromatic plants from Midi-Pyrénées (France) and Chongqing (China) regions

Zhao, Tianming 12 May 2014 (has links)
Les régions de Midi-Pyrénées (France) et de Chongqing (Chine) sont riches en plantes aromatiques et médicinales dites oubliées (ou médiévales). Afin de valoriser pleinement les différentes bio-molécules extractibles de ces plantes, le concept de MAP-raffinerie a été créé et appliqué à une sélection de plantes issues de ces deux régions. Plusieurs technologies d’extraction utilisant l’eau comme solvant vert (hydrodistillation, distillation à la vapeur et extraction par eau sub-critique) ont ainsi été employées et leur impact tant sur la composition des huiles essentielles que sur la récupération des molécules anti-oxydantes a été évalué. Dans un premier temps, une liste de plantes aromatiques et médicinales oubliées, voire sous-utilisées dans les deux régions a été établie selon des règles de sélection prédéfinies. Six plantes modèles de la région de Midi-Pyrénées (Tussilago farfara L., Calendula arvensis L., Robinia pseudoacacia L., Geranium robertianum L., Cytisus scoparius L. et Spartium junceum L.) et trois plantes de la région de Chongqing (Tussilago farfara L., Citrus aurantium L. et Saussurea costus) ont finalement été retenues. Puis, le concept de MAP-raffinerie a été appliqué à ces plantes afin d’étudier leur possible valorisation globale. L’étude des compositions chimiques des extraits volatils des racines de Tussilago farfara L. et de Calendula arvensis L., ainsi que des boutons de fleurs de Spartium junceum L. a été réalisée par GC et GC-MS pour la première fois. Les principaux composés chimiques dans l’extrait volatil de racines de Tussilago farfara L. étaient des hydrocarbures sesquiterpéniques et des composés aliphatiques tandis que les principaux composés chimiques dans l’extrait volatil de racines de Calendula arvensis L. étaient des sesquiterpènes oxygénés, des monoterpènes oxygénés et des diterpènes oxygénés. L’extrait volatil de boutons de fleurs de Spartium junceum L. était principalement composé de composés aliphatiques. Par ailleurs, les résultats de l’évaluation des capacités anti-oxydantes des extraits (par les tests DPPH, ABTS, FRAP, ORAC et Folin-Ciocalteu) ont montrés que plusieurs plantes comme Cytisus scoparius L., Tussilago farfara L., Citrus aurantium L. ou Robinia pseudoacacia L. pourraient être des sources potentielles d’anti-oxydants naturels. D’un point de vue technologique, les comparaisons de l’utilisation de l’hydrodistillation (HD), de la distillation à la vapeur (SD) et de l’extraction par eau sub-critique (SWE) ont montrées que si la HD et la SD ont des effets limités sur la composition des huiles essentielles, la HD semble être une méthode plus efficace pour la récupération des composés anti-oxydants à partir des résidus de distillation que la SD tandis que la SWE s’avère être une technologie prometteuse pour l’extraction directe de ces molécules à partir des plantes. Si la composition minérale de l’eau lors de l’hydrodistillation n’a que des effets très limités sur les rendements d’extraction, les teneurs en ions calcium et bicarbonate des eaux ont par contre des effets décroissants significatifs sur la capacité anti-oxydante et sur la teneur phénolique totale des extraits aqueux et méthanoliques. Au vue de ces résultats, un concept amélioré de MAP-raffinerie a été développé en intégrant une extraction à l’eau sub-critique pour l’extraction des composés anti-oxydants des résidus d’extraction primaire. Selon ce nouveau concept, cinq extraits peuvent être obtenus à partir des matières végétales: un extrait volatil, un extrait aqueux, un extrait méthanolique, un extrait à l’eau sub-critique et in fine un résidu solide. Les premiers résultats ont montrés que la "MAP-raffinerie améliorée" augmente de manière significative la récupération des antioxydants par rapport à la MAP-raffinerie originale et permet d’envisager une valorisation plus facile du résidu solide en agro-matériaux du fait de sa faible teneur en eau résiduelle. / In both Midi-Pyrénées region (France) and Chongqing region (China), there are rich and underutilized medicinal and aromatic plants (MAP). Aiming at fully exploiting different molecules in these plants, the concept of MAP-refinery was developed and applied to several underutilized medicinal and aromatic plants in these two regions. Several water-based green extraction technologies of natural products (e.g. hydrodistillation, steam distillation and subcritical water extraction) were also investigated to look at their effects on essential oil composition and antioxidants recovery from selected plants. Firstly, lists of forgotten or underutilized medicinal and aromatic plants in both regions were established according to the rules of selection. From the lists, six plants in the Midi-Pyrénées region (Tussilago farfara L., Calendula arvensis L., Robinia pseudoacacia L., Geranium robertianum L., Cytisus scoparius L. and Spartium junceum L.) and three plants in the Chongqing region (Tussilago farfara L., Citrum aurantium L. and Saussurea costus) were finally selected for investigations. Then the MAP-refinery was applied to the selected plants in two regions in order to realise their global valorisation. Volatile extracts composition in the roots of Tussilago farfara L. and Calendula arvensis L., as well as flower buds of Spartium junceum L. were firstly investigated. The main chemical compounds in volatile extract from Tussilago farfara L. roots were sesquiterpene hydrocarbons and aliphatic compounds while main chemical compounds in volatile extract from Calendula arvensis L. roots were oxygenated sesquiterpenes, oxygenated monoterpenes and oxygenated diterpenes. The volatile extract from flower buds of Spartium junceum L. was mainly composed of aliphatic compounds. Antioxidant capacity evaluation results (by DPPH, ABTS, FRAC, ORAC and Folin-Ciocalteu tests) showed that several plant samples like Cytisus scoparius L., Tussilago farfara L., Citrum aurantium L. and Robinia pseudoacacia L. could be potential sources of natural antioxidants. Comparisons of hydrodistillation (HD), steam distillation (SD) and subcritical water extraction (SWE) showed that HD and SD had limited effects on essential oil composition but HD, SD and SWE had significant impacts on the recovery of antioxidants. Hydrodistillation seemed to be a better method for recovery of antioxidant compounds from residues of distillation than steam distillation. However, SWE appeared to be a more efficient method for direct extraction of antioxidant molecules (or phenolic compounds) from plants. In the hydrodistillation process, mineral contents in water were found to have very limited effects on yields of extracts but calcium and bicarbonate ions, had significant decreasing effects on antioxidant capacity and total phenolic content of both aqueous and methanolic extracts. Finally, an improved MAP-refinery was developed. Subcritical water was used for further extraction of antioxidant compounds from residues in original MAP-refinery. In this way, five parts could be obtained from plant materials: volatile extract, aqueous extract, methanolic extract, subcritical water extract and the final residue. The results showed that the improved MAP-refinery significantly increased the recovery of antioxidants compared with original MAP-refinery. This promising process will also allow a better valorisation of the final solid residue due to the lower content of residual water.
417

New Strategies to Enhance the Quality and Safety of Liquid Foods Based on the Use of Natural Antimicrobial Compounds

Gómez Llorente, Héctor 02 September 2024 (has links)
Tesis por compendio / [ES] Los componentes de los aceites esenciales (CAEs) han demostrado ser eficaces contra una amplia variedad de microorganismos. Sin embargo, su aplicación plantea desafíos debido a su baja solubilidad y alteración de las propiedades organolépticas en los alimentos. Por tanto, la búsqueda de nuevas formas de dosificación es fundamental para promover su uso en la industria alimentaria. La presente tesis doctoral está centrada en el desarrollo y aplicación de sistemas antibacterianos y antivirales basados en la inmovilización covalente de CAEs para mejorar la calidad y seguridad de alimentos líquidos. El primer capítulo evaluó el efecto de la adición de componentes naturalmente presentes en los alimentos (proteínas, lípidos, carbohidratos, ácidos orgánicos y etanol) sobre la actividad antimicrobiana de diferentes CAEs (carvacrol, eugenol, geraniol, timol y vainillina) en su forma libre. Además, se evaluó la influencia de los componentes alimentarios sobre la vainillina inmovilizada. Los resultados mostraron que la albúmina sérica bovina (BSA), el aceite de girasol y algunos carbohidratos fueron los componentes que más inhibieron la actividad antimicrobiana de los CAEs libres, con algunas excepciones. En los medios que contienen BSA, no se inhibió la actividad antimicrobiana del geraniol. Lo mismo ocurrió con eugenol en aceite de girasol, o con carvacrol, eugenol, geraniol y timol en presencia de D-lactosa. La vainillina inmovilizada confirmó el efecto inhibidor de las proteínas, lípidos y carbohidratos sobre la actividad antimicrobiana, pero el ácido cítrico y el etanol mejoraron la actividad antimicrobiana. Estos resultados demuestran la importancia de considerar la composición de la matriz alimentaria al seleccionar un compuesto antimicrobiano. El segundo capítulo evaluó la aplicación de CAEs frente al crecimiento y producción de guaiacol por un microorganismo alterante y termorresistente como Alyciclobacillus acidoterrestris en zumo de naranja. Para ello, se utilizaron CAEs inmovilizados con dos enfoques diferentes: como aditivos y como coadyuvantes tecnológicos. La presencia de CAEs provocó una reducción microbiana y una inhibición de la producción de guayacol, que fue mantenida tras la inmovilización. Este hecho es de gran interés, ya que la inmovilización evita el problema de alteración organoléptica del producto, derivado de la aplicación de estos antimicrobianos en forma libre. En el tercer capítulo se estudió la actividad antiviral de los CAEs, tanto en forma libre como inmovilizada, frente al virus Tulane en agua. La aplicación de CAEs en forma libre logró una reducción de la infectividad de sólo 1 log10, mientras que concentraciones equivalentes de antimicrobiano inmovilizado redujeron la infectividad a más de 4,5 log10. Por otro lado, el mecanismo antiviral se basó en la modificación o alteración de cápside viral. Además, se determinó que los CAEs inmovilizados no son citotóxicos en concentraciones antivirales efectivas. A pesar de la eficacia observada tras la inmovilización de los CAEs, su aplicación práctica en la industria alimentaria presenta varios desafíos, siendo uno de ellos la aceptación de esta tecnología por parte de los consumidores. El último capítulo estudió la percepción de los consumidores sobre el uso de la nanotecnología en el procesamiento de alimentos. La valoración de los distintos alimentos en los que se había aplicado nanotecnología en su procesamiento o envasado fue en general positiva. De todos los productos, aquellos en los que la nanotecnología no formaba parte de los alimentos recibieron la mejor valoración. Teniendo en cuenta este resultado, los CAEs inmovilizados aplicados como coadyuvantes tecnológicos serían los más valorados y, por tanto, podrían ser una excelente alternativa a los tratamientos de conservación convencionales, para controlar tanto virus como bacterias durante la producción y el almacenamiento de alimentos. / [CA] Els components dels olis essencials (COEs) han demostrat ser eficaços en fornt d'una àmplia varietat de microorganismes. Tot i això, la seua aplicació planteja desafiaments a causa de la seua baixa solubilitat i alteració de les propietats organolèptiques en els aliments. Per tant, la recerca de noves formes de dosificació és fonamental per promoure'n l'ús a la indústria alimentària. Aquesta tesi doctoral està centrada en el desenvolupament i l'aplicació de sistemes antibacterians i antivirals basats en la immobilització covalent de COEs per a millorar la qualitat i la seguretat d'aliments líquids. El primer capítol va avaluar l'efecte de l'addició de components naturalment presents als aliments (proteïnes, lípids, carbohidrats, àcids orgànics i etanol) sobre l'activitat antimicrobiana de diferents COEs (carvacrol, eugenol, geraniol, timol i vainillina) en la seua forma lliure. En aquesta primera part també es va avaluar la influencia dels components alimentaris sobre la vainillina immobilitzada. Els resultats van mostrar que l'albúmina sèrica bovina (BSA), l'oli de gira-sol i alguns carbohidrats van ser els components que van inhibir més l'activitat antimicrobiana dels COEs lliures, amb algunes excepcions. Als mitjans que contenen BSA no es va inhibir l'activitat antimicrobiana del geraniol. El mateix va passar amb eugenol en oli de gira-sol, o amb carvacrol, eugenol, geraniol i timol en presencia de D-lactosa. La vainillina immobilitzada va confirmar l'efecte inhibidor de les proteïnes, els lípids i els carbohidrats sobre l'activitat antimicrobiana, però l'àcid cítric i l'etanol van millorar l'activitat antimicrobiana. Aquests resultats demostren la importància de considerar la composició de la matriu alimentària quan s'ha de seleccionar un compost antimicrobià per a una aplicació concreta. El segon capítol va avaluar l'aplicació de COEs en front del creixement i la producció de guaiacol per un microorganisme alterant i termorresistent com Alyciclobacillus acidoterrestris en suc de taronja. Per això, es van utilitzar COEs immobilitzats amb dos enfocaments diferents: com a additius i com a coadjuvants. La presència de COEs provoca una reducció microbiana i una inhibició de la producció de guaiacol, així com manté la seua eficàcia després de la immobilització. Aquest fet és de gran interès, ja que la immobilització evita el problema d'alteració organolèptica del producte, derivat de l'aplicació d'aquests antimicrobians en forma lliure. Al tercer capítol es va estudiar l'activitat antiviral dels COEs, tant en forma lliure com immobilitzada, davant del virus Tulane en aigua. L'aplicació de COEs en forma lliure va aconseguir una reducció de la infectivitat de només 1 log10, mentre que concentracions equivalents d'antimicrobià immobilitzat van reduir la infectivitat a més de 4,5 log10. D'altra banda, es va comprobar que el mecanisme antiviral es va basar en la modificació o alteració de la càpside viral. A més, es va determinar que els COEs immobilitzats no són citotòxics en concentracions antivirals efectives. Tot i l'eficàcia observada després de la immobilització dels COEs, la seua aplicació pràctica a la indústria alimentària presenta diversos desafiaments, un dels quals és l'acceptació d'questa tecnologia per part dels consumidors. El darrer capítol va estudiar la percepció dels consumidors sobre l'ús de la nanotecnologia en el processament d'aliments. La valoració dels diferents aliments en que s'havia aplicat nanotecnologia al seu processament o envasat va ser en general positiva. De tots els productes, aquells en que la nanotecnologia no formava part dels aliments van rebre la millor valoració. Tenint en compte aquest resultat, els COEs immobilitzats aplicats com a coadjuvants de processament serien els més valorats i, per tant, podrien ser una alternativa excel·lent als tractaments de conservació convencionals, per controlar tant virus com bacteris durant la producció i l'emmagatzematge d'aliments. / [EN] Essential oil components (EOCs) have proven to be effective against a wide variety of microorganisms. However, the direct application of these compounds poses challenges due to their low solubility and alteration of the organoleptic properties of foods. Therefore, the search for new dosage forms of these promising antimicrobials is essential to promote their use in the food industry. The present doctoral thesis is focused on the development and application of antibacterial and antiviral systems based on the covalent immobilization of EOCs to improve the quality and safety of liquid foods. The first chapter evaluated the effect of the addition of components naturally present in food (proteins, lipids, carbohydrates, organic acids and ethanol) on the antimicrobial activity of certain EOCs (carvacrol, eugenol, geraniol, thymol and vanillin) in their free form. In this first part, the influence of these food components on the antimicrobial activity of vanillin immobilized on silicon oxide particles was also evaluated. The results showed that bovine serum albumin (BSA), sunflower oil and some carbohydrates were the food components that most inhibited the antimicrobial activity of the free EOCs, with some exceptions. In media containing BSA the antimicrobial activity of geraniol was not inhibited. The same occurred with eugenol in media containing sunflower oil, or with carvacrol, eugenol, geraniol and thymol in media with D-lactose. Immobilized vanillin confirmed the inhibitory effect of the proteins, lipids and carbohydrates on the antimicrobial activity, but citric acid and ethanol enhanced the antimicrobial activity. These results demonstrate the importance of considering the composition of the food matrix when selecting an antimicrobial compound. The second chapter evaluated the application of EOCs against the growth and production of guaiacol by a spoilage and heat-resistant microorganism such as Alyciclobacillus acidoterrestris in orange juice. For this purpose, EOCs immobilized on silicon oxide particles were used with two different approaches: as additives and as processing aids. The presence of EOCs causes a microbial reduction and an inhibition of guaiacol production, maintaining their effectiveness after immobilization. This fact is of great interest, since immobilization avoids the problem of organoleptic alteration of the product, derived from the application of these antimicrobials in free form. In the third chapter, the antiviral activity of EOCs, both in free and immobilized form, against Tulane virus in water was studied. The application of EOCs in free form achieved a reduction in infectivity of only 1 log10, equivalent concentrations of immobilized antimicrobial reduced infectivity to more than 4.5 log10. On the other hand, it has been demonstrated that the antiviral mechanism is based on the ability of immobilized antimicrobials to modify or disrupt the viral capsid. Furthermore, it was determined that immobilized EOCs are not cytotoxic at effective antiviral concentrations. Despite the efficacy observed after immobilization of EOCs against bacteria and viruses, their practical application in the food industry presents several challenges, one of them is the acceptance of this technology by consumers. Thus, the last chapter studied the perception of consumers regarding the use of nanotechnology in food processing. The evaluation of the different foods in which nanotechnology had been applied in their processing or packaging was generally positive, and most consumers would buy them. Of all the products, those in which nanotechnology was not part of the food received the best evaluation. Considering this result, immobilized EOCs applied as processing aids would be the most highly valued, and therefore could be an excellent alternative to conventional preservation treatments, to control both viruses and bacteria during food production and storage. / This research forms part of project PID2021-128141OB-C21 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. H.G.LL. acknowledges the Universitat Politécnica de València for his predoctoral fellowship. The authors acknowledge native English translator Helen Warburton for editing the text. The authors gratefully acknowledge the financial support from the project PID2021-128141OB-C21 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. This work is also granted by the project TED2021- 132035B-I00, funded by MCIN/AEI/10.13039/501100011033 and by “European Union NextGenerationEU/PRTR”. CG-B thanks the financial support received from the Spanish State Agency of Research (PID2022-136963OBI00/AEI/10.13039/501100011033), the Xunta de Galicia [ED431C 2021/29 and Centro singular de investigación de Galicia accreditation 2019-2022 (ED431G 2019/03)], and the European Regional Development Fund (ERDF). H.G.LL. acknowledges the Universitat Politècnica de València for his predoctoral fellowship. The authors gratefully acknowledge the financial support from the project PID2021- 128141OB-C21 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. This work is also granted by the project TED2021-132035B-I00, funded by MCIN/AEI/10.13039/501100011033 and by “European Union NextGenerationEU/PRTR”. H.G.LL. acknowledges the Universitat Politècnica de València for his predoctoral fellowship.The authors gratefully acknowledge the financial support for the experiment reported herein from the Spanish Government (RTI2018-101599-B-C21-AR). Héctor Gómez Llorente wishes to thank the Universitat Politècnica de València for the FPI Grant. / Gómez Llorente, H. (2024). New Strategies to Enhance the Quality and Safety of Liquid Foods Based on the Use of Natural Antimicrobial Compounds [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/207284 / Compendio

Page generated in 0.1122 seconds