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  • 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.
11

Solvent-free Microwave Extraction And Microwave-assisted Hydrodistillation Of Essential Oils From Spices

Bayramoglu, Beste 01 September 2007 (has links) (PDF)
ABSTRACT SOLVENT-FREE MICROWAVE EXTRACTION AND MICROWAVEASSISTED HYDRODISTILLATION OF ESSENTIAL OILS FROM SPICES Bayramoglu, Beste M.S., Department of Food Engineering Supervisor: Assoc. Prof. Dr. Serpil Sahin Co-Supervisor: Assoc. Prof. Dr. S. G&uuml / l&uuml / m S&uuml / mn&uuml / September 2007, 130 pages The undesirable effects of conventional methods generated the need for economical and safe techniques in the extraction of essential oils. Microwave-assisted hydrodistillation (MAHD) and solvent-free microwave extraction (SFME) are recently developed techniques, which are thought to overcome this problem. Oregano (Origanum vulgare L.), laurel (Laurus nobilis L.) and rosemary (Rosmarinus officinalis L.) were chosen in this study since they have high antimicrobial and antioxidant effects and are widely grown and consumed in Turkey. The objectives of this study were to examine the applicability of SFME in the extraction of essential oils from oregano and laurel, and MAHD in the extraction of rosemary essential oil. The effects of microwave power and extraction time on the yield, composition, and other quality parameters of the extracts were also investigated. Hydrodistillation was performed as control. SFME offered significantly higher essential oil yields (0.054 mL oil/g oregano) from oregano as compared to hydrodistillation (0.048 mL oil/g oregano). Conventional process time was reduced by 80%. Main aroma compound was thymol (650-750 mg thymol/mL oil). For laurel, no significant differences were obtained in yields (about 0.022 mL oil/g laurel) obtained by SFME and hydrodistillation. Process time was reduced by 55-60%. Main aroma compound was 1,8-cineole (630-730 mg 1,8-cineole/mL oil). In the case of rosemary, no significant differences were obtained in yields (about 0.026 mL oil/g rosemary) obtained by MAHD at 622 W and hydrodistillation. The process time was reduced by about 65%. Main aroma compounds were 1,8-cineole (430-500 mg 1,8-cineole/mL oil) and camphor (150-210 mg camphor/mL oil). Keywords: Solvent-free microwave extraction (SFME), Microwave-assisted hydrodistillation (MAHD), Origanum vulgare L., Laurus nobilis L., Rosmarinus officinalis L.
12

Analyse des mélanges complexes de volatils issus des végétaux.

Muselli, Alain 12 December 2007 (has links) (PDF)
Ce travail constitue un recueil des mes activités d'enseignement et de recherche postdoctorales réalisées au sein du laboratoire " Chimie des Produits Naturels " (CPN) dans le cadre du projet de recherche " Ressources Naturels " soutenu par l'UMR CNRS 6134 " Sciences de l'Environnement " de l'Université de Corse Pasquale Paoli. Les travaux concernent la caractérisation des Plantes aromatiques et médicinales (PAM) et des produits de l'agroalimentaire au travers des mélanges complexes volatils qui en sont issus. Ces mélanges complexes sont des huiles essentielles, des hydrolats, des extraits aux solvants et des fractions volatiles. Les différentes étapes de la séquence analytique ont été examinées à savoir, le choix des végétaux et leur échantillonnage, la préparation de l'échantillon, son analyse proprement dite, l'interprétation des résultats au moyen de l'outil statistique et leur valorisation au travers de la recherche de principes actifs. La première partie vise à caractériser les huiles essentielles, les hydrolats, les extraits aux solvants et les fractions volatiles issus de PAM et ainsi que les arômes des huiles d'olives et de jus d'agrumes. Pour cela, nous avons examiné les potentialités de méthodes dites alternatives à l'hydrodistillation, méthode conventionnelle pour l'obtention des huiles essentielles et des hydrolats, telles que l'extraction assistée par micro-ondes et la MicroExtraction en Phase Solide. L'analyse proprement est réalisée au laboratoire CPN à l'aide de techniques chromatographiques telles que la Chromatographie en Phase Gazeuse (CPG) pour la quantification et la CPG couplée à la Spectrométrie de Masse (CPG-SM) pour l'identification des constituants des mélanges. Nous avons optimisé la séquence analytique en utilisant la complémentarité des techniques telles que la chromatographie sur colonne, l'utilisation de la SM en mode ionisation chimique et de la Résonance Magnétique Nucléaire pour l'identification de molécules absentes des bibliothèques de références. La deuxième partie concerne le développement d'un axe de recherche nouveau qui vise à mettre en évidence des principes actifs au travers de l'étude des propriétés antibactériennes et antifongiques des huiles essentielles et des extraits de végétaux. Nous avons mis en évidence les propriétés biologiques d'huiles essentielles et d'extraits sur un certain nombre de bactéries impliquées dans des infections nosocomiales et alimentaires. La dernière partie développe les perspectives de travail qui visent à renforcer les travaux sur les PAM et sur les produits identitaires de l'agroalimentaire produits en Corse en explorant de nouvelles matrices d'études (fraction lourde) et de nouvelles techniques d'extraction. La valorisation des mélanges complexes issus des végétaux par la recherche de nouveaux antibiotiques surpassant les mécanismes de résistance des bactéries et de nouveaux antioxydants reste un challenge scientifique d'avenir.
13

Estudo químico de Annona coriacea Mart. E Xylopia aromatica (Lam.) Mart. (Annonaceae) / Chemical study of Annona coriacea Mart. and Xylopia aromatica (Lam.) Mart. (Annonaceae)

Junqueira, João Gabriel Moraes 26 March 2015 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2016-01-29T13:15:45Z No. of bitstreams: 2 Dissertação - João Gabriel Moraes Junqueira - 2015.pdf: 5620624 bytes, checksum: b030b0a7744d9893a10756f4cef1821c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2016-01-29T13:17:29Z (GMT) No. of bitstreams: 2 Dissertação - João Gabriel Moraes Junqueira - 2015.pdf: 5620624 bytes, checksum: b030b0a7744d9893a10756f4cef1821c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-01-29T13:17:29Z (GMT). No. of bitstreams: 2 Dissertação - João Gabriel Moraes Junqueira - 2015.pdf: 5620624 bytes, checksum: b030b0a7744d9893a10756f4cef1821c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-03-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / CHAPTER 01: CHEMICAL STUDY OF VOLATILE ORGANIC COMPOUNDS Annona coriacea Mart. AND Xylopia aromatica (Lam.) Mart (Annonaceae) - In this research was performed the study of the chemical profile of the volatile organic compounds (VOCs) of flowers and leaves of species Annona coriacea and Xylopia aromatica (Annonaceae) by means of extraction in vivo and in vitro, through the techniques headspace-solid phase microextraction (HS-SPME), hydrodistillation and characterization by gas chromatography-mass spectrometry (GC-MS). By the analysis of the volatile fraction of flowers and leaves of A. coriacea it was observed different VOCs, according to the coatings utilized, since the selection of the fiber becomes one of the main factors for VOCs analysis in different vegetables parts. The chemical profile of the flowers of X. aromatica was obtained through HS-SPME, which compared the efficiency of in vivo and in vitro extractions, due to the higher number of VOCs present in the floral aroma. Once were obtained various chemical data, the multivariate analysis of the data was performed, which provided relevant information, contributing to the optimization of some conditions, such as selection of fiber, extraction time and extraction temperature yielded the characterization of the most number of VOCs. In this context, the conditions that presented the most promising results were: fibers CAR/PDMS and PA, extraction time equal the 60 min and extraction temperature of 29 °C. The essential oil of the flowers of X. aromatica was obtained by hydrodistillation and chemically characterized by GC-MS. The major compound present was the pentadecan-2-one (16.38%). The extraction techniques utilized were helpful, however there was qualitative and quantitative variation of VOCs, which is expected due to the extraction process be different. Thus, it is observed that depending on the objective of the survey or that searches for in the volatile fraction, it is necessary to use the technique to give the most promising results for the investigation held or in order to complement each other. In this way, the study of A. coriacea and X. aromatica contributed to the knowledge of the chemical profile of VOCs present in these species, seen from these investigations that the same can be applied in several industrial areas, for example cosmetic, food, among others. / CAPÍTULO 01: ESTUDO QUÍMICO DOS COMPOSTOS ORGÂNICOS VOLÁTEIS DE Annona coriacea Mart. E Xylopia aromatica (Lam.) Mart (Annonaceae) - Nesta pesquisa realizou-se o estudo do perfil químico dos compostos orgânicos voláteis (COVs) das flores e folhas das espécies Annona coriacea e Xylopia aromatica (Annonaceae), por meio da extração in vivo e in vitro, através das técnicas de headspace-microextração em fase sólida (HS-SPME), hidrodestilação e caracterização via cromatografia gasosa acoplada à espectrometria de massas (CG-EM). Pela análise da fração volátil das flores e folhas de A. coriacea observou-se COVs diferentes, de acordo com os revestimentos usados, visto que a seleção da fibra se torna um dos principais fatores para a análise de COVs em partes vegetais diferentes. O perfil químico das flores de X. aromatica foi obtido via HS-SPME, em que se comparou a eficiência das extrações in vivo e in vitro, em função do maior número de COVs presentes no aroma floral. Uma vez que foram obtidos vários dados químicos, foi realizada a análise multivariada dos mesmos, a qual forneceu informações relevantes, contribuindo para a otimização de algumas condições, tais como seleção da fibra, tempo de extração e temperatura de extração que rendessem a caracterização do maior número de COVs. Neste contexto, as condições que apresentaram os resultados mais promissores foram: fibras de CAR/PDMS e PA, tempo de extração igual a 60 min e temperatura de extração de 29 oC. O óleo essencial das flores de X. aromatica foi obtido por hidrodestilação e caracterizado quimicamente por CG-EM. O composto majoritário presente foi a pentadecan-2-ona (16,38%). As técnicas de extração utilizadas foram úteis, entretanto houve variação quali e quantitativa dos COVs, o que é esperado devido ao processo de extração ser diferente. Assim, observou-se que dependendo do objetivo da pesquisa ou do que se procura na fração volátil, faz-se necessária a utilização da técnica que dê os resultados mais promissores para a investigação realizada ou de forma que se complementem. Desta maneira, o estudo de A. coriacea e X. aromatica contribuiu para o conhecimento do perfil químico dos COVs presentes nestas espécies, visto que a partir destas investigações os mesmos podem ser aplicados em várias áreas industriais, por exemplo cosmético, alimentos, dentre outros.
14

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.

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