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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.
1

Pilot scale process for polysaccharide extraction and fractionation from cereal by-products

Rudjito, Reskandi Chastelia January 2017 (has links)
No description available.
2

Extraction des molécules à haute valeur ajoutée par eau sous critique et fractionnement par procédés membranaires : Valorisation des co-produits de la vigne et du vin par des procédés éco-innovants / Extraction of high-value added compounds by subcritical water and fractionation by membrane processes : Valorization of vine and wine by-products by eco-innovative processes

Yammine, Sami 03 May 2016 (has links)
Ce travail a porté sur l'extraction de substances naturelles de sous-produits de la vigne en mettant en œuvre des procédés "verts" tels que l'extraction par eau sous-critique et la purification par filtration membranaire. Ces procédés représentent une alternative à l'extraction par solvant, traditionnellement utilisée dans la production de substances bio-sourcées. La majeure partie de cette étude a été menée sur des marcs de raisin de cépages variés, l'extraction a été optimisée et comparée sur la base du rendement, de la composition chimique et de l'activité antioxydante des extraits obtenus. De tous les cépages testés, les extraits de Dunkelfelder ont présenté l'activité antioxydante la plus élevée et la concentration en familles de molécules polyphénoliques la plus importante. En outre, ce marc de raisin de Dunkelfelder a été utilisé comme modèle afin d'optimiser les différents paramètres du procédé tels que la température, la pression et le temps de séjour hydraulique. Après la phase d'extraction par eau sous-critique, les extraits obtenus se sont révélés riches en de nombreuses familles de molécules. Ainsi, une étape de purification des composés cibles avant usage industriel s'est révélée indispensable. Le couplage de l'extraction par eau sous-critique avec des procédés membranaires représente une solution innovante pour la purification de ces extraits. Des essais de filtration tangentielle de l'extrait ont été menés avec onze membranes d'ultrafiltration (100 kDa à 2 kDa) et neuf membranes de nanofiltration (1000 Da à 150 Da). Le suivi du procédé s’est appuyé sur une détermination des paramètres opératoires optimisés et sur la détermination des coefficients de rétention des différentes familles des macro et micromolécules. Les résultats obtenus ont démontré que l'utilisation des technologies membranaires pourrait dans le futur, constituer une innovation technologique pour la purification des composés bio-actifs / This work has dealt with extraction of natural substances from winery by-products using "green" processes such as extraction by subcritical water and purification by membrane processes. These processes are an alternative to solvent extraction traditionally used in the natural products industry. Main part of the work was done on different grape pomace, extraction was optimized and compared in terms of yield, chemical composition, and antioxidant activity of extracts. Dunkelfelder extracts exhibited the strongest antioxidant activity and comparison of chemical compositions of the different extracts indicated. Furthermore this Dunkelfelder grape pomace was used as model in order to optimize the different process parameters such as temperature, pressure and hydraulic retention time. After the subcritical water extraction, extracts produced were found to be rich in several families of molecules. An essential purification step of target compounds prior to industrial use was indispensable. Coupling the subcritical water with membrane processes offers an innovative solution for the purification of these extracts. Thereby, the extract was assayed in a cross-flow apparatus against eleven membranes of ultrafiltration (100 to 2 kDa) and nine membranes of nanofiltration (1000 to 150 Da). The monitoring of the process was carried out by determining performance parameters and retention coefficients of different families of macro and micromolecules. The results obtained have demonstrated that the use of membrane technologies could bring innovative changes in the recovery of bioactive compounds for future industries.
3

Cascade Valorization of Apple Pomace into Polyphenols and Pectins by Green Extraction Processes / Utvinning av Äpplepress till Polyfenoliska Ämne och Pektin genom Gröna Extraktionsprocesser

Gál, Teodóra January 2020 (has links)
I det här projektet extraherades värdefulla komponenter från äpple-pomace som är en restprodukt från cidertillverkning. Restprodukten var tillhandahållen av en svensk cidertillverkare. Extraktionen fokuserades mot pektin och fenolföreningar som uppvisar antioxiderande aktivitet. Extraktionsprocessen designades ur ett miljövänligt perspektiv, inga skadliga kemikalier användes. Fenolära substanser extraherades initialt från pomacen med en vattenlösning innehållande 50% etanol. Därefter studerades kompositionen och den antioxiderande aktiviteten i dessa extrakt. Fokuseringen i projektet låg främst på pektin. Pektin extraherades med subkritiskt vatten vid tre olika pH (3,5 och 7) samt vid två skilda temperaturer (120°C och 140°C) i antingen 5, 10 och 15 minuters sekvenser. Pektinet karakteriserades med avseende på extraktionsutvinningsgrad, sockerkomposition, molekylvikt och antioxiderande aktivitet. Resultaten jämfördes för att undersöka effekten av pH, temperatur och extraktionstid. Gelningsegenskapen hos olika pektin studerades som ett bevis på koncept i ett empiriskt experiment där hög-viskösa vätskor bestående av 5% pektin och 60% sackaros framställdes. Extraherade fenolföreningar har potential att fungera som naturligt utvunna antioxidanter i kosmetiska produkter och pektin kan tänkas användas som reologimodifierare i vattenbaserade formuleringar med låga pH-värden utan behov av kemiska modifieringar. / In this project, apple pomace from a Swedish cider making factory as a by-product was used as a raw material to extract valuable compounds. The extraction was focused on pectin and phenolic compounds with antioxidant activity. For the extraction procedures environmentally friendly processes were chosen without using any harsh chemicals. Phenolic compounds wereinitially extracted from the pomace using 50% aqueous ethanol and then the composition, total phenolic content and antioxidant activity were studied in these extracts. The main focus was on pectins, which were extracted by subcritical water at three different pH conditions (pH 3, 5 and 7) and two different temperatures (120°C and 140°C) in 5-, 10- and 15 minute sequences. Then the pectins were characterized in terms of extraction yield, sugar composition, molecular weight and antioxidant activity and the results were compared in terms of the effect of pH, temperatur eand extraction time. The gelling properties of the different pectins were also studied as a proof of concept in an empirical experiment, where highly viscous liquids were obtained at 5% pectinand 60% sucrose content. In summary, the extracted phenolic compounds have potential to function as naturally derived antioxidants in cosmetics and the pectin may be used as a rheology modifier in water-based formulations of low pH without any additional chemical modifications.
4

Comparison of Corn and Rye Arabinoxylans for the Production of Bio-based Materials / Jämförelse av arabinoxylaner från råg och majs för tillverkning av biobaserade material

Chen, Chen January 2020 (has links)
Enzymes and subcritical water can be used for the extraction of hemicelluloses from cereal by-products, making the processes eco-friendly. The polysaccharides extracted from cereal by-products can be used as matrices for development of materials for various applications. This includes bio-based materials such as films and hydrogels, which offer alternatives to existing materials produced from petrochemicals. The polymeric structure of cereal hemicelluloses contains functional groups which enable the modification of their structure by cross-linking, resulting in the formation of hydrogels. This project aims to use subcritical water extraction (SWE) to extract arabinoxylans (AXs) from corn and rye bran meanwhile the enzymatic treatment is done for purifying the samples during both pre- and post-treatment. AXs were further crosslinked by enzyme (laccase) for hydrogel preparation. During the whole project, the characterization included moisture and yield determination, starch and protein content which were tested using a spectrophotometer, monosaccharide content was analyzed by high performance anion exchange chromatography followed by pulsed amperometric detection (HPAEC-PAD) and phenolic acid content was quantified by high performance liquid chromatography (HPLC). The pretreatment for destarching and SWE process was successful. The result showed that arabinoxylans form corn bran were having higher content of arabino substituents, arabino toxylans ratio and ferulic acid content than rye samples. The enzymatic crosslinking could form strong gels in the condition that the AXs had high ferulic acid content. In terms of forming strong hydrogels or to improving the properties of AXs gel, the pre- and post-treatment should be optimized to increase the purity of the extracted feruloylated AX content. / Enzymer och subkritiskt vatten kan användas för extraktion av hemicellulosa från spannmålsbiprodukter, vilket gör extraktionen miljövänlig. Polysackariderna extraherade från spannmålsprodukter kan användas som matriser för utveckling av material för diverse applikationer. Detta inkluderar biobaserade material som filmer och hydrogeler, där petrokemikalier kan ersättas som råvara. Den polymera strukturen hos spannmålshemicelluloser innehåller funktionella grupper som möjliggör formation av tvärbindningar vilket resulterar i bildandet av hydrogeler. Syftet med detta projekt är extraktion av arbinoxylaner (AXs) från majs och rågkli genom att använda subkritiskt vatten-extraktion (SWE) där rening under för- och efterbehandling utförs enzymatiskt. AX modifierades därefter enzymatiskt (laccas) med tvärbindningar för hydrogelframställning. Under hela projektet karakteriserades hydrogelen utifrån fuktinnehåll, bestämmelse av utbyte, stärkelse och proteininnehåll som testades med en spektrofotometer, monosackaridhalten analyserades med högpresterande anjonsutbyteskromatografi följt avpuls-amperometrisk detektion (HPAEC-PAD), samt kvantifierades fenolsyrahalten med högupplöst vätskekromatografi (HPLC). Resultatet visade att arabinoxylaner från majskli hade högre innehåll av arabinosubstituenter, där förhållandet mellan arabino och xylans, samt arabino och ferulsyra innehållet var högre än för rågproverna. Den enzymatiska tvärbindningen kunde bilda starka geler i det tillståndet där AX hade en hög ferulsyrahalt. När det gäller att bilda starka hydrogeler eller att förbättra egenskaperna hos AXs-gel, bör för-och efterbehandlingen optimeras för att öka renheten fördet extraherade feruloylerade AX-innehållet.
5

Оптимизација савремених екстракционих поступака за изоловање апигенина из цвета камилице (Chamomilla recutita L.) и карактеризација биолошке активности добијених екстраката / Optimizacija savremenih ekstrakcionih postupaka za izolovanje apigenina iz cveta kamilice (Chamomilla recutita L.) i karakterizacija biološke aktivnosti dobijenih ekstrakata / Optimization of novel extraction techniques for apigenin isolation from chamomile flowers (Chamomilla recutita L.) and characterization of biological activity of obtained extracts

Cvetanović Aleksandra 02 December 2016 (has links)
<p>У оквиру ове докторске дисертације изведено је<br />испитивање различитих екстракционих поступака за<br />изоловање апигенина из цвета камилице, као и евалуација<br />биолошке активности добијених екстраката. Полазни<br />биљни материјал сачињавале су две групе латица<br />камилице: ферментисане и неферментисане (нативне).<br />Екстракција ферментисаних цветова је извођена применом<br />ултразвучне екстракције користећи етанол као екстрагенс,<br />а добијени екстракти су се одликовали изузетно високим<br />садржајем апигенина. Оптимизација екстракције је била<br />изведена применом методе одзивне површине. Применом<br />електрон-спин резонанце испитана је антирадикалска<br />активност екстраката. Додатно, фармаколошка вредност<br />добијених екстраката је потврђена и одређивањем њиховог<br />антимикробног и антипролиферативног потенцијала.<br />Нативни цветови камилице су екстраховани применом<br />различитих екстаркционих техника: микроталасне,<br />ултразвучне, Soxhlet екстракције као и екстракције<br />субкритичном водом. Eкстрaкција водом у субкритичном<br />стању се показала супериорнијом у односу на све остале<br />технике у погледу садржаја укупних фенола и флавоноида.<br />У циљу добијања екстраката са максималним садржајем<br />апигенина изведена је оптимизација овог екстракционог<br />процеса. Изоловање чистог апигенина је изведено из<br />екстракта добијеног под оптималним екстракцијом<br />условима (однос дрога:растварач 1:30, брзина мешања 3 Hz,<br />притисак 45 bar, температура 115&ordm;C, време 30 мин,<br />концентрација модификатора 0,001 М) применом поступка<br />колонске хроматографије на стубу полиамида. Хемијски<br />профил као и садржај појединачних полифенолних<br />компонената у екстрактима добијеним на различитим<br />притисцима, температурама и уз присуство модификатора<br />различитих концентрација одређен је применом UHPLCDAD-<br />HESI-MS/MS. У свим анализираним екстрактима<br />детектован је велики број полифенолних компонената, док<br />је апигенин у свима био доминантно једињење. Садржај<br />апигенина у екстракту добијеном под оптималним<br />екстракционим условима је износио 1.700,34 mg/kg.<br />Применом седам различитих тестова извршена је<br />евалуација антиоксидативног и антирадикалског<br />потенцијала екстраката. Антимикробни потенцијал<br />екстраката је одређен за осам различитих микробних<br />линија. in vitro тестовима испитана је способност<br />инхибиције &alpha;-амилазе, &alpha;-глукозидазе и тирозиназе.<br />Деловањем на раст три хистолошки различите ћелијске<br />линије, испитана је антипролиферативна активност<br />екстраката добијених субкритичном водом.<br />Антимотилитетна активност обе групе екстраката<br />(ферментисаних и неферментисаних цветова) одређена је у<br />in vitro условима.</p> / <p>U okviru ove doktorske disertacije izvedeno je<br />ispitivanje različitih ekstrakcionih postupaka za<br />izolovanje apigenina iz cveta kamilice, kao i evaluacija<br />biološke aktivnosti dobijenih ekstrakata. Polazni<br />biljni materijal sačinjavale su dve grupe latica<br />kamilice: fermentisane i nefermentisane (nativne).<br />Ekstrakcija fermentisanih cvetova je izvođena primenom<br />ultrazvučne ekstrakcije koristeći etanol kao ekstragens,<br />a dobijeni ekstrakti su se odlikovali izuzetno visokim<br />sadržajem apigenina. Optimizacija ekstrakcije je bila<br />izvedena primenom metode odzivne površine. Primenom<br />elektron-spin rezonance ispitana je antiradikalska<br />aktivnost ekstrakata. Dodatno, farmakološka vrednost<br />dobijenih ekstrakata je potvrđena i određivanjem njihovog<br />antimikrobnog i antiproliferativnog potencijala.<br />Nativni cvetovi kamilice su ekstrahovani primenom<br />različitih ekstarkcionih tehnika: mikrotalasne,<br />ultrazvučne, Soxhlet ekstrakcije kao i ekstrakcije<br />subkritičnom vodom. Ekstrakcija vodom u subkritičnom<br />stanju se pokazala superiornijom u odnosu na sve ostale<br />tehnike u pogledu sadržaja ukupnih fenola i flavonoida.<br />U cilju dobijanja ekstrakata sa maksimalnim sadržajem<br />apigenina izvedena je optimizacija ovog ekstrakcionog<br />procesa. Izolovanje čistog apigenina je izvedeno iz<br />ekstrakta dobijenog pod optimalnim ekstrakcijom<br />uslovima (odnos droga:rastvarač 1:30, brzina mešanja 3 Hz,<br />pritisak 45 bar, temperatura 115&ordm;C, vreme 30 min,<br />koncentracija modifikatora 0,001 M) primenom postupka<br />kolonske hromatografije na stubu poliamida. Hemijski<br />profil kao i sadržaj pojedinačnih polifenolnih<br />komponenata u ekstraktima dobijenim na različitim<br />pritiscima, temperaturama i uz prisustvo modifikatora<br />različitih koncentracija određen je primenom UHPLCDAD-<br />HESI-MS/MS. U svim analiziranim ekstraktima<br />detektovan je veliki broj polifenolnih komponenata, dok<br />je apigenin u svima bio dominantno jedinjenje. Sadržaj<br />apigenina u ekstraktu dobijenom pod optimalnim<br />ekstrakcionim uslovima je iznosio 1.700,34 mg/kg.<br />Primenom sedam različitih testova izvršena je<br />evaluacija antioksidativnog i antiradikalskog<br />potencijala ekstrakata. Antimikrobni potencijal<br />ekstrakata je određen za osam različitih mikrobnih<br />linija. in vitro testovima ispitana je sposobnost<br />inhibicije &alpha;-amilaze, &alpha;-glukozidaze i tirozinaze.<br />Delovanjem na rast tri histološki različite ćelijske<br />linije, ispitana je antiproliferativna aktivnost<br />ekstrakata dobijenih subkritičnom vodom.<br />Antimotilitetna aktivnost obe grupe ekstrakata<br />(fermentisanih i nefermentisanih cvetova) određena je u<br />in vitro uslovima.</p> / <p>In the frame of this thesis different extraction approaches for<br />apigenin isolation from chamomile ligulate flowers were<br />examined and biological activity of obtained extracts was<br />evaluated. Starting plant samples included fermented and<br />nonfermented (native) flowers.<br />Extraction of fermented flowers was performed by using<br />ultrasound-assisted extraction with ethanol. The concentration<br />of apigenin was high in obtained extracts. Optimization of the<br />extraction procedures was performed by response surface<br />methodology. Antiradical activity of observed extracts was<br />examined by electron-spin resonance spectroscopy.<br />Furthermore, pharmacological potential of obtained extracts<br />was confirmed by determining their antimicrobial and<br />antiproliferative activity.<br />Native chamomile flowers were extracted by different<br />extraction techniques: microwave, ultrasound, Soxhlet and<br />subcritical water extraction. Subcritical water extraction<br />showed to be superior in comparison to other applied techniques<br />in respect to total phenols and flavonoids content. Optimization<br />of the subcritical water extraction was directed to maximization<br />of apigenin content. Isolation of pure apigenin from extracts<br />obtained under optimal extraction conditions (sample-tosolvent<br />ratio 1:30, agitation rate 3 Hz, temperature 115&ordm;C,<br />pressure 45 bar, extraction time 30 min) was performed by<br />preparative chromatography. Chemical profiles and content of<br />individual polyphenolic components in extracts obtained at<br />different pressures, temperatures, and with different<br />concentrations of a modifier was determined by UHPLC-DADHESI-<br />MS/MS. In all analyzed extracts the great number of<br />polyphenolic components was detected while apigenin was the<br />dominant compound in all extracts. Content of apigenin in the<br />extract obtained under optimal extraction condition was<br />1,700.34 mg/kg. Antioxidant and antiradical potential of<br />extracts was evaluated according to different mechanisms.<br />Antimicrobial potential of extracts was determined against eight<br />different microbial strains. Ability of extracts to inhibit &alpha;-<br />amylase, &alpha;-glucosidase and tyrosinase was determined by in<br />vitro assays. Antiproliferative activity of subcritical water<br />extracts was defined by testing their influence on the growth of<br />three histologically different cell lines.<br />Anti-intestinal motility activity of both group of extracts (native<br />and fermented) was determined by in vivo experiments.</p>
6

Iskorišćenje sporednog proizvoda uve (Arctostaphylos uva ursi L.) u cilju dobijanja novih biljnih ekstrakata savremenim tehnikama ekstrakcije / Utilization of uva (Arctostaphylos uva ursi L.) by product in order to obtain new herbal extracts by modern extraction techniques

Naffati Abdulhakim 01 February 2019 (has links)
<p style="text-align: justify;">U okviru ove doktorske disertacije ispitana je mogućnost ekstrakcije bioaktivnih jedinjenja iz biljne pra&scaron;ine A. uva-ursi, koja nastaje kao sporedni proizvod u fabrici filter čaja. Za ekstrakciju bioaktivnih jedinjenja primenjene su različite tehnike ekstrakcije (klasična ekstrakcija, ultrazvučna ekstrakcija i ekstrakcija subkritičnom vodom), kao i različiti ekstragensi: voda na sobnoj temperaturi, 30-70% etanol i subkritična voda. Sadržaj bioaktivnih jedinjenja u ekstraktima ispitan je primenom odgovarajućih spektrofotometrijskih metoda i HPLC metode. U ekstrakciji biljne pra&scaron;ine A. uva-ursi detaljno je matematički analiziran uticaj procesnih parametara na ekstrakciju subkritičnom vodom bioaktivnih jedinjenja iz materijala ovog tipa i u tom smislu je posmatran uticaj temperature, vremena i dodatka kiseline, a takođe su određeni uslovi pri kojima je, primenom ove tehnike, moguće ostvariti maksimalnu ekstrakciju bioaktivnih jedinjenja od značaja. Pored toga prikazana je i mogućnost primene spray drying tehnike za su&scaron;enje tečnih i proizvodnju suvih ekstrakta A. uva-ursi u formi praha. Na kraju, na osnovu koncentracije bioaktivnih jedinjenja i njihovog delovanja, dat je predlog nekoliko novih preparata na bazi ekstrakata A. uva-ursi, u tečnoj i čvrstoj formi.</p> / <p>This dissertation investigated the possibility to extract bioactive compounds from A. uva-ursi herbal dust, which occurs as a by-product at the filter-tea<br />factory. Various extraction techniques (classical extraction, ultrasound assisted extraction and subcritical water extraction), were applied for the extraction of bioactive compounds, as well as different solvents: water at room temperature, 30-70% ethanol and subcritical water. The content of bioactive compounds in the extracts was investigated using appropriate spectrophotometric methods and the HPLC method. In the extraction of A. uva-ursi herbal dust a detailed mathematical analysis of the influence of process parameters on subcritical water extraction of bioactive compounds from this type of material was conducted. In this regard the influence of temperature, time and acid addition was observed and the conditions under which it is possible to achieve maximum extraction of significant bioactive compounds, by applying this technique, were determined. In addition, the possibility of applying the spray drying technique for drying the liquid and producing dry A. uva-ursi extracts in the form of powder is also presented. Eventually, based on the concentration of the bioactive compounds and their activity, a proposal for a several new preparations in liquid and solid form, based on A. uva-ursi extracts is given.</p>
7

New methods for determination of airborne pollutants : Focus on tetrabromobisphenol A, organophosphate triesters and polycyclic aromatic hydrocarbons

Tollbäck, Johanna January 2009 (has links)
The work presented in this thesis concerns the development and evaluation of new methods of sampling and analysis of organic pollutants in the indoor and outdoor environment. In Paper I, the development of a new method was reported for the determination of the brominated flame retardant tetrabromobisphenol A (TBBPA) in air using sampling with glass fiber filter and polyurethane foam (PUF), ultrasonic solvent extraction and liquid chromatography coupled to electrospray ionisation mass spectrometry (LC-ESI/MS). The MS fragmentation mechanism of TBBPA was thoroughly investigated and different acquisition modes were evaluated to achieve the most sensitive and selective detection. In Papers II and III, the potential use of Empore SPE membranes was evaluated for air sampling of volatile, semi-volatile and particle-associated organic compounds. Breakthrough studies conducted for 24h at air flows of 10- 20 L/min showed that the SPE membranes efficiently retains volatile and semi-volatile organophosphate esters and particles &gt;10 nm. Effort was invested in the development of fast and environmental friendly methods, with low cost, for sample clean up and analysis. In Paper II, the sample preparation technique was dynamic solvent extraction with methanol coupled to LC-ESI/MS. The total run time per sample, including both extraction and separation, was less than 34 min, consuming only 1.6mL methanol. In Paper III, efficiency of selective extraction of polycyclic aromatic hydrocarbons from particulate matter sampled with Empore SPE membranes, using dynamic subcritical water extraction (DSWE) was investigated. Acceptable recoveries of the investigated compounds from reference material (SRM 1649a) were achieved. In Paper IV, the application of dynamic solid phase micro-extraction (SPME) air sampling was evaluated using, gas chromatography/positive ion chemical ionisation (GC/PICI) and tandem-MS detection for the determination of organophosphate esters in work environment.
8

Optimizacija ekstrakcionih postupaka i karakterizacija ekstrakata korena gaveza (Symphytum officinale), lista duda (Morus nigra) i peteljki trešnje (Prunus avium) / Optimization of extraction techniques andcharacterization of comfrey root (Symphytum officinale), black mullberry leaves (Morus nigra )and sweet cherry stems (Prunus avium) extracts

Nastić Nataša 09 July 2020 (has links)
<p>U okviru ove doktorske disertacije ispitane su i<br />poređene različite ekstrakcione tehnike korena<br />gaveza, lista crnog duda i peteljki tre&scaron;nje. Poređene<br />su konvencionalne i savremene ekstrakcione<br />tehnike i izvedena je optimizacija ekstrakcionih<br />postupaka s ciljem dobijanja ekstrakata ispitivanih<br />biljnih vrsta sa najvećom bioaktivno&scaron;ću. Za svaku<br />ekstrakcionu tehniku ispitan je uticaj najznačajnijih<br />parametara: maceracija (rastvarač i vreme<br />ekstrakcije), ubrzana ekstrakcija (temperatura i<br />rastvarač), supekritična ekstrakcija (pritisak i<br />koncentracija ko-rastvarača) i ekstrakcija<br />subkritičnom vodom (temperatura, pritisak, vreme<br />ekstrakcije i brzina me&scaron;anja). Ekstrakcija polifenola<br />korena gaveza, lista crnog duda i peteljki tre&scaron;nje je<br />bila najefikasnija ekstrakcijom subkritičnom<br />vodom. Primenjene su tehnika visokopritisne tečne<br />hromatografije spregnute sa masenom<br />spektrometrijom uz primenu različitih masenih<br />analizatora, masenog analizatora na bazi vremena<br />preleta jona i tandema kvadrupolnog i analizatora<br />na bazi vremena preleta jona. Za karakterizaciju<br />dobijenih ekstrakata instrumentalnom analizom su<br />određene kvalitativne i kvantitativne karakteristike dobijenih ekstrakata korena gaveza, lista crnog duda i peteljki tre&scaron;nje. HPLC-ESI-QTOF-MS/MS analizom ekstrakata identifikovano je vi&scaron;e od 27 novih jedinjenja različitih hemijskih klasa u svakom od ispitivanih biljnih matriksa.</p> / <p>Within the scope of this doctoral dissertation,<br />different extraction techniques of comfrey root,<br />black mulberry leaves and sweet cherry stems were<br />applied and compared. Conventional and novel<br />extraction techniques were optimized and<br />compared in order to obtain plant extracts with the<br />highest content of bioactive compounds. The<br />influence of the most important parameters was<br />investigated for each extraction technique:<br />maceration (solvent and extraction time),<br />accelerated solvent extraction (temperature and<br />solvent), supercritical fluid extraction (co-solvent<br />percentage and pressure) and subcritical water<br />extraction (temperature, pressure, extraction time<br />and agitation rate). Extraction of polyphenolic<br />compounds from comfrey root, black mulberry<br />leaves and sweet cherry stems was the most<br />effective using subcritical water. High-pressure<br />liquid chromatography coupled to mass<br />spectrometry techniques using time-of-flight and<br />quadrupole-time-of-flight mass analyzers have<br />been used to characterize bioactive compounds.<br />Qualitative and quantitative characteristics of the<br />obtained comfrey root, black mulberry leaves and sweet cherry stem extracts were determined. HPLC-ESI-QTOF-MS/MS revealed the presence of more than 27 compounds of different chemical classes that have been identified for the first time in&nbsp; the plant matrix.</p>
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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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