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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.
111

Tecnologia para produção de extrato aquoso de amendoim e elaboração de produto fermentado

Pretti, Taciana [UNESP] 24 June 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-24Bitstream added on 2014-06-13T19:09:10Z : No. of bitstreams: 1 pretti_t_me_arafcf.pdf: 649581 bytes, checksum: 01a43b71b827a486ed71045fb400a33b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Visando ampliar o aproveitamento nutricional e tecnológico do amendoim realizou-se este trabalho, com o objetivo de elaborar extrato aquoso, com diferentes processamentos, e verificar a aceitação do extrato fermentado com Streptococcus thermophilus e Lactobacillus delbrueckii ssp bulgaricus e com adição de leite em pó desnatado. O procedimento para obtenção do extrato consistiu no aquecimento dos grãos em solução de bicarbonato de sódio a 0,5% (1:4, p/v) até ebulição, com posterior drenagem, lavagem, desintegração e filtração. Foram avaliadas duas temperaturas (75 ºC e 97 ºC) e duas proporções de grão: água (1:5 e 1:8, p/v) para a desintegração dos grãos. Os produtos fermentados, com 0%, 2% e 4% de leite em pó, foram avaliados sensorialmente. Água a 75 ºC produziu extrato com o menor conteúdo de lipídeos (5,87%) e maior de carboidratos (2,31%). Os componentes dos extratos foram significativamente diluídos com a maior proporção de água (1:8 p/v), que permitiu o maior rendimento (1:6,92 kg), a maior extração de sólidos totais e proteína e a menor perda de sólidos no resíduo, sendo este procedimento selecionado para elaboração do extrato fermentado. O aquecimento dos grãos a 97 ºC propiciou proteína com maior digestibilidade (80,6%). Os resultados mostraram a possibilidade de se elaborar um produto adequado, fermentando-se o extrato de amendoim adicionado de leite em pó. Apresentou pH 4,5, 0,5% de ácido lático, 4,86% proteína e 2,36% de lipídeos e características sensoriais aceitáveis. A adição de leite em pó desnatado favoreceu a fermentação (4 horas e meia), melhorou a consistência e a aceitação geral do produto fermentado. O extrato aquoso fermentado de grãos de amendoim é uma alternativa tecnológica viável à elaboração de alimentos para a população, pela qualidade nutricional de seus componentes e a sua fácil disponibilidade. / Aiming to increase nutritional and technological utilization of the peanut, this research was realized to produce an aqueous extract, with variations in processing, and to check the acceptance of the fermented extract with Streptococcus thermophilus and Lactobacillus delbrueckii ssp bulgaricus and with the addition of powder milk. The procedure to obtain the extract consisted of heating the beans until boiling (1:4 w/v) 0.5% of sodium bicarbonate, draining, washing, disintegration and filtration. It was evaluated two temperatures (75 ºC and 97 ºC) and two amounts of grain: water (1:5 and 1:8, w/v) in disintegration of the grains. Fermented products, with 0%, 2% and 4% of powder milk, were evaluated. Water at 75 ºC produced extract with lower content of lipids (5.87%), and higher of carbohydrates (2.31%). The extracts components of the were significantly diluted with the proportion 1:8 w/v, that permited the highest yield of process (1:6.92 kg) and better total solids and protein extraction and lower loss of solids in the waste. It was therefore selected for preparation of the fermented extract. The heating of the grains at 97 ºC, due to better digestibility of protein (80.6%). The results showed that is possible to obtain a fermented product with peanut extract added at milk powder. It presented pH 4.5, 0.5% lactic acid, 4.86% protein and 2.36% lipids and sensorial quality. The addition of powder milk favored fermentation (4 hours) and improved the consistency and general acceptance of the fermented product. The aqueous extract fermented of peanut grains represents a viable technological alternative in the preparation of food for population, due to nutritional quality of its components and its easy availability.
112

Utilização de zeólitas sintetizadas a partir de cinzas de carvão na remoção de corante em água / Utilization of zeolites synthesized from fly ash on the removal of dye from aqueous solution

BRUNO, MARIZA 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:52:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:13Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
113

Síntese de zeólitas de cinzas de carvão modificada por surfactante e aplicação na remoção de ácido laranja 8 de solução aquosa: estudo em leito móvel, coluna de leito fixo e avaliação ecotoxicológica / Synthesis of zeolites coal ash in surfactant modified in application and removal of orange 8 acid solution: study in batch, fixed bed column and evaluation ecotoxicological

MAGADALENA, CARINA P. 10 April 2015 (has links)
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-04-10T14:03:59Z No. of bitstreams: 0 / Made available in DSpace on 2015-04-10T14:03:59Z (GMT). No. of bitstreams: 0 / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
114

Reação em cadeia da polimerase e proteinograma no diagnóstico da leishmaniose ocular canina /

Barbosa, Virginia Tessarine. January 2011 (has links)
Orientador: José Luis Laus / Banca: Aline Adriana Bolzan / Banca: Leucio Camara Alves / Banca: Fábio Luiz da Cunha Brito / Banca: Newton Nunes / Resumo: A leishmaniose ocular canina envolve um complexo de alterações decorrentes da atuação do agente nos diversos tecidos oculares. Valendo-se de cães com sorologia positiva para a doença, portadores (G1) ou não (G2) de alterações oftálmicas, com este estudo avaliou-se: o exame parasitológico de esfregaço a partir de swab conjuntival, a presença do parasito, pela PCR, em fragmento conjuntival e no humor aquoso (HA) e as concentrações protéicas, pela eletroforese, no HA. O parasitológico de esfregaço a partir do swab conjuntival foi positivo em 60% e 38,1% dos animais do G1 e do G2, respectivamente, com a oddsratio de 2,438 para positividade em tal parâmetro nos cães do G1, comparativamente aos do G2. A positividade na PCR de fragmento conjuntival foi maior no G1 (p < 0,005), com oddsratio igual a 17,31 quando comparados G1 e G2. O parasito não foi detectado no HA de qualquer dos grupos. Houve correlação fracopositiva entre as concentrações de IgG e de albumina séricas e do HA. Diferenças significativas foram encontradas entre os grupos, quando comparadas as proteínas totais, IgG, e proteína de peso molecular 33 kDa no HA. A haptoglobina foi detectada apenas no HA dos cães do G1. Os dados apontam para uma tendência dos cães com sinais oftálmicos serem positivos no parasitológico de esfregaço a partir do swab conjuntival e na PCR de conjuntiva, podendo, o método ser útil no diagnóstico parasitológico da leishmaniose visceral canina. Proteínas de fase aguda merecem mais avaliações quanto ao seu valor diagnóstico para esta enfermidade / Abstract: Canine ocular leishmaniasis involves several ophthalmic alterations owing to the action of the parasite in numerous ocular tissues. Therefore, dogs serologically positive for leishmaniasis either presenting (G1) or not (G2) ocular alterations were enrolled in this study to evaluate the conjunctival cytology as a method for the diagnosis of this disease, the detection of the parasite in conjunctival tissue samples and in the aqueous humor using PCR, as well as the serum and aqueous humor protein concentrations determined by electrophoresis. The parasitological evaluation of the swabs disclosed 60% and 38.1% of positivity in dogs of groups 1 and 2, respectively, with a calculated oddsratio of 2.438 for a single animal testing positive in this procedure when ocular changes existed. The documented PCR results were more expressive in G1 dogs (P<0,005), with an oddsratio of 17,81 for the animals of this group testing positive using this method as compared to G2. The parasite was not found in the aqueous humor of either group. A weak positive correlation was calculated between the serum and aqueous humor IgG and albumin concentrations, and significant differences were found to exist between groups regarding total protein, IgG, and 33 kDa protein measured in the aqueous humor. Also, haptoglobin was detected only in the aqueous humor of G1 dogs. Our data suggest a tendency of dogs with ocular signs testing positive on the conjunctival swab exams and PCR, being these methods useful in the diagnosis of canine leishmaniasis. However, acute phase proteins require a more detailed evaluation concerning its diagnostic value for this disease / Doutor
115

Utilização de zeólitas sintetizadas a partir de cinzas de carvão na remoção de corante em água / Utilization of zeolites synthesized from fly ash on the removal of dye from aqueous solution

BRUNO, MARIZA 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:52:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:13Z (GMT). No. of bitstreams: 0 / Os experimentos de adsorção descontínuos foram realizados para remover azul de metileno de solução aquosa usando zeólitas sintetizadas a partir de cinza leve de carvão como adsorvente. Os estudos foram conduzidos para avaliar os efeitos do tempo de contato, concentração inicial do corante, parâmetros de ativação hidrotérmica, composição da cinza leve, quantidade do adsorvente, pH e temperatura sobre a adsorção. Um tempo de contato de aproximadamente 10 minutos foi suficiente para a adsorção do corante alcançar o equilíbrio. Os dados de equilíbrio foram analisados usando as isotermas de Langmuir e Freundlich e os resultados se ajustaram melhor à equação da isoterma de Freundlich. A eficiência de adsorção estava entre 72 a 98% sob as condições estudadas. O valor da constante de Freundlich para a capacidade de adsorção (KF) do azul de metileno no adsorvente foi 0,738 (mg/g) (L/mg)1/n. Os dados de adsorção foram ajustados aos modelos cinéticos de pseudoprimeira- ordem de Lagergren e pseudo-segunda-ordem e seguiram as cinéticas de pseudosegunda- ordem. As constantes de velocidade foram estimadas em diferentes concentrações iniciais. O mecanismo do processo de adsorção encontrado mostrou-se complexo, consistindo de adsorção superficial e difusão intrapartícula. Os parâmetros termodinâmicos foram avaliados indicando que o processo de adsorção do azul de metileno sobre a zeólita é espontâneo e exotérmico. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
116

Síntese de zeólitas de cinzas de carvão modificada por surfactante e aplicação na remoção de ácido laranja 8 de solução aquosa: estudo em leito móvel, coluna de leito fixo e avaliação ecotoxicológica / Synthesis of zeolites coal ash in surfactant modified in application and removal of orange 8 acid solution: study in batch, fixed bed column and evaluation ecotoxicological

MAGADALENA, CARINA P. 10 April 2015 (has links)
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-04-10T14:03:59Z No. of bitstreams: 0 / Made available in DSpace on 2015-04-10T14:03:59Z (GMT). No. of bitstreams: 0 / No presente estudo, material zeolítico sintetizado a partir de cinzas de carvão e modificado por surfactante catiônico foi utilizado na remoção do corante ácido laranja 8 (AL8) por processo de adsorção utilizando leito móvel e coluna de leito fixo. As matérias primas e os adsorventes foram caracterizados por diferentes técnicas, tais como: difração de raios-x, fluorescência de raios-X, entre outras. A adsorção do AL8 foi realizada por leito móvel com o objetivo de otimizar os resultados quando lançados em leito fixo. Os efeitos na adsorção do AL8 sobre zeólita foram comparados: (1) efeito dos contra-íons Br- e Cl- do surfactante usado na modificação da zeólita; (2) efeito do tipo de cinzas de carvão usada como matéria prima na síntese das zeólitas (leve e pesada). Os seguintes adsorventes foram utilizados no estudo: zeólita leve e pesada modificada por surfactante brometo de hexadeciltrimetilamônio (ZLMS-Br e ZPMS-Br) e zeólita leve modificada por surfactante cloreto de hexadeciltrimetilamônio (ZLMS-Cl). A cinética de pseudo-segunda-ordem descreveu a adsorção do corante sobre todos os adsorventes. O tempo de equilíbrio alcançado foi 40, 60 e 120 min para ZLMS-Br, ZLMS-Cl e ZPMS-Br, respectivamente. O equilíbrio de adsorção foi analisado pelas equações dos modelos das isotermas lineares e não lineares de Langmuir, Freundlich, Temkin e Dubinin-Radushkevivh (DR) e o critério de melhor ajuste foi avaliado usando as funções erros. O modelo DR ajustou-se melhor aos dados experimentais para o sistema AL8/ZLMS-Br, o modelo de Freundlich para AL8/ZLMS-Cl e Langmuir para AL8/ZPMS. Segundo Langmuir a capacidade máxima de adsorção foi 4,67 , 1,48 e 1,38 mg g-1 para ZLMS-Br, ZLMS-Cl e ZPMS-Br, nesta ordem. Nos estudos empregando-se colunas de leito fixo, os efeitos da concentração de entrada (20 - 30 mg L-1), vazão de alimentação (4,0 - 5,3 mL min-1) e a altura do leito (5,5 - 6,5 cm) sobre as características da curva de ruptura no sistema de adsorção foram determinados. Os modelos Bohart-Adams, Thomas, Yoon-Nelson foram aplicados aos dados experimentais para a previsão das curvas de ruptura e para a determinação dos parâmetros que caracterizam a coluna. Os modelos matemáticos de Thomas e Yoon-Nelson se ajustaram satisfatoriamenete aos dados das curvas de ruptura. A maior capacidade total de remoção do AL8 pela coluna de leito fixo apresentou o valor de 5,30 mg g-1 obtida com a concentração do corante de 30 mg L-1, altura do leito de 5,5 cm e uma vazão de alimentação de 5,3 mL min-1. Os ensaios de ecotoxicidade aguda utilizando o microcrustáceo Daphnia similis com o efluente bruto (AL8) e após tratamento com zeólita leve modificada com surfactante foram realizados com o propósito de avaliar evidências de uma possível contaminação quando lançados no corpo hídrico receptor. Os resultados obtidos neste estudo mostraram que as amostras do corante AL8 em solução aquosa não apresentou efeito tóxico e as amostras tratadas com ZLMS-Br apresentaram toxicidade. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
117

Sobre a cristalização de esferas de poliestireno em suspensão aquosa / About crystallization of polystyrene spheres in aqueous suspension

Maria Keiko Udo 16 August 1979 (has links)
Foi estudada a cristalização de suspensões aquosas de esferas de poliestireno (850&#197, 910&#197 e 1090&#197 de diâmetro) no limite de baixas concentrações -1011 a 1013 esferas / cm3. A dependência do parâmetro de rede com a concentração original (n) da suspensão aquosa apresenta uma transição de fase da fase bcc para fcc, conforme já foi observada por outros autores. Observamos também que durante a cristalização a concentração de esferas no cristal Ra sistematicamente maior do que na solução original, portanto a água estaria sendo expelida para a solução durante a cristalização. Baseado nestas observações nós propomos um modelo de cristalização onde os cristalites (concentração n1) estão em equilíbrio termodinâmico com uma solução com concentração n2 (n1&#62 n &#62 n2), dando para cada concentração inicial um diferente parâmetro de rede determinado por este equilíbrio. Nossos resultados mostraram que o coeficiente de expulsão da água durante a cristalização é dependente do raio da esfera. Para realizar as medidas de parâmetro de rede nós adaptamos para as nossas condições particulares o método de Debye-Scherrer usado em difração de raios-X por cristais. O equivalente à fonte de raios-X era um laser de Argônio com comprimentos de onda variáveis. Diversas experiências novas são sugeridas. / The crystallization of aqueous suspensions of polystyrene spheres 850&#197, 910&#197 and 1090&#197 of diameter) was studied in the limit of low concentration -1011 to 1013 spheres / cm3. The dependence of the lattice parameter with the original concentration (n) of the aqueous suspension shows a phase transition from bcc to fcc phase as it was already been observed by others authors. We also observed that during crystallization the concentration of spheres in the crystal was systematically higher than in the original solution, showing that water should be expelled toward the solution during crystallization where the crystallites (concentration n1) are in thermodynamic equilibrium with a solution with concentration n2 (n1&#62 n &#62 n2) giving for each initial concentration a different lattice parameter determined by this equilibrium. Our results showed that coefficient of water rejection during crystallization is dependent on the sphere radius. In order to make the measurements of the lattice parameter we adapted to our particular conditions the Debye-Scherrer method used in X-ray diffraction of crystals. The equivalent to the X-ray source was a tunable Argon laser. Several new experiments are suggested.
118

Monoclonal antibody (mAb) purification by counter current chromatography (CCC)

Fernando, Samantha January 2011 (has links)
Counter current chromatography (CCC) is a form of liquid liquid chromatography, which the Brunel Institute for Bioengineering (BIB) team have developed to process scale. In this thesis, its application has been successfully extended to the rapid, scalable purification of monoclonal antibodies (mAb) from mammalian cell culture, using aqueous two-phase systems (ATPS) of inorganic salts and polymer. A polyethylene glycol (PEG) and sodium citrate system was found to be the most appropriate by robotic phase system selection. The search for an economical alternative to protein A HPLC is a substantial bioprocessing concern; in this work CCC has been investigated. Initial studies showed that unpredictably, despite separation from impurities being achieved, some loss in the IgG‘s ability to bind to Protein A was seen, as confirmed by Protein A BiaCore analysis. CCC machines were seen to adversely affect IgG functionality. This led to a systematic investigation of the effect of CCC phase mixing on IgG functionality in a number of different CCC instruments, allowing direct comparisons of modes of CCC (hydrodynamic and hydrostatic CCC) and their associated mixing (wave-like and cascade, respectively). The varying g forces produced within the CCC column were determined using a recently developed model to calculate g force range. The effect of interfacial tension was also studied using a custom built 'g' shaker. The optimum CCC mode was identified to be the non synchronous CCC, operated in a hydrodynamic mode but allowing bobbin to rotor speed (Pr ratio) to be controlled independently. In a normal synchronous J type centrifuge a Pr of 1 is fixed, this is where the bobbin and rotor speed are identical I.e. one bobbin rotation (where mixing occurs) to one rotor revolution (where settling occurs). Constraints were seen with this 1:1 ratio and the separation of mAb using ATPS. This work has shown with the use of the non synchronous CCC at a Pr of 0.33, mixing is reduced and rotor rotations increased. Consequently the associated g force range is decreased. Furthermore, by the extension of settling time, the clear separation of the mAb from impurities has been achieved with retention of biological activity. This thesis demonstrates the importance of settling time for ATPS in phase separation and documents the fundamental requirements for the successful separation of biologics. Purified non synchronous CCC samples have additionally undergone rigorous quality control testing at Lonza Biologics by their purification scientists. This work has ultimately showed that with optimisation, the non synchronous CCC can be used to produce biological samples that are of industry standard.
119

Confinement de la détonation d'un objet explosif par mousse aqueuse sèche. Etude expérimentale et numérique / Confinement of an Explosive Device Detonation Using Dry Aqueous Foam. Experimental and Numerical Study

Ballanger, Félix 03 October 2016 (has links)
Dans un contexte de protection des biens et des personnes, le CEA DAM s’intéresse aux mousses aqueuses pour leur capacité à confiner une détonation.D’une part, le but est d’atténuer les effets de souffle liés à la détonation d’un engin explosif. D’autre part, il est souhaitable de ralentir ou de capturer les particules solides, potentiellement nocives, qui pourraient être dispersées.L’objectif de cette thèse est de comprendre les phénomènes physiques sous-jacents à ces deux problématiques, au travers de la réalisation d’expériences et de leur modélisation numérique.Les mousses aqueuses sont des milieux diphasiques, assemblages de bulles de gaz encapsulées dans une matrice de films liquides et de Bords de Plateau.Cette étude se concentre sur les mousses communément dites sèches, i.e. dont la fraction volumique de liquide est inférieure à 5%. Les travaux réalisés sont présentés en trois grandes parties. La première concerne la propagation des ondes de choc dans les mousses aqueuses. Elle présente une campagne expérimentale en tube à choc, menée à l’ENSTA Bretagne, dont les résultats permettent la mise en évidence de l’influence du gaz composant la mousse sur le ralentissement et l’atténuation du front de choc.La deuxième partie s’intéresse à l’atténuation des ondes de souffle issues d’une détonation. Deux campagnes ont été conduites : l’une à l’ISAE-ENSMA en mettant en œuvre un tube à détonation rempli d’un mélange réactif gazeux, l’autre au CEA/Gramat en utilisant la détonation d’un explosif solide en champ libre. Ces deux configurations amènent à l’observation de l’atténuation des phénomènes de souffle provenant de la détonation.Le modèle numérique qui s’appuie sur un formalisme multiphasique compressible, a permis d’appréhender la phénoménologie et l’importance relative des différents mécanismes de transferts entre phases, en y incluant notamment deux étapes de fragmentation de la mousse. Les résultats expérimentaux des trois précédentes campagnes et les résultats numériques sont en très bon accord.La dernière partie concerne l’étude du ralentissement et de la capture de particules micrométriques par la mousse aqueuse. Deux campagnes ont été menées à cet effet. La première consiste à étudier la dynamique à haute vitesse d’un nuage de particules métalliques, qui a été projeté par un explosif au sein d’une mousse. A l’aide de radiographies X, la position et la forme du nuage sont analysées au cours de sa propagation. Le freinage des particules parla mousse est manifeste. La deuxième campagne quantifie le taux de particules capturées par un confinement de mousse aqueuse.Ainsi, une comparaison de la dispersion de particules métalliques micrométriques a été effectuée pour différentes tailles de confinement. Ces résultats ont permis d’attester des bonnes propriétés de capture des particules dispersées par une charge explosive dans les mousses aqueuses. / In order to improve the protection of goods and persons, the French CEA DAM is interested in aqueous foams for their ability to mitigate the detonation outcome. Two objectives are put forward. The first one is to attenuate the blast effects induced by the detonation of an explosive device. The second one is to slow down or to capture potentially harmful solid particles, which could be dispersed by the considered device.As such, the aim is to understand the underlying physics of such phenomenon. Several experiments have been undertaken and compared to a multiphase numerical modelling.Aqueous foam is a two-phase medium, composed of gaseous bubbles within a liquid matrix made of films and Plateau Borders. This study focuses on dry aqueous foams, i.e. with a liquid volumic fraction lower than 5%. The presentation of the study is divided into three parts. The first one deals with the shock wave propagation through aqueous foam. An experimental campaign on a shock tube, at ENSTA Bretagne, is presented, whose results highlight the influence of the gas which fills the cells of the foam on the shock front behavior.The second part is related to the blast wave attenuation. Two experimental campaigns were conducted: one in a detonation tube with a reactive gaseous mixture, at ISAE-ENSMA and another one, using condensed explosive, at CEA/Gramat. In both cases, the results lead to the mitigation of the detonation induced blast effects.There is a good agreement between these three experimental results and the numerical results from the multiphase model. This enables us to clarify the phenomenology and quantify the different interphase exchange, which evolve as the foam fragmentation proceeds in two steps.The last part is about the aqueous foam ability to slow down or to capture micrometric particles. Two campaigns were conducted on this subject. The first one studied the high velocity dynamics of a cloud of particles propelled by an explosive into an aqueous foam. Using X-ray radiography, both the position and the shape of the cloud are analysed during its propagation through the foam. A strong decrease in speed of the particles is observed. The second campaign aimed to quantify the particle ratio captured by an aqueous foam confinement. To that end, several sizes of aqueous foam confinement have been compared. The results show the good properties of the foam to inhibit the particle dispersal by an explosive.
120

Stability of freeze-dried aqueous and other modified extracts of Leonotis leonurus

Basson, Ilana Alison January 2017 (has links)
Magister Pharmaceuticae - MPharm / Leonotis leonurus, a South African indigenous medicinal plant, is frequently used in the form of a tea. However, this dosage form has many disadvantages. Consequently three L. leonurus solid extract preparations were prepared and explored as possible replacements of the tea form, but very little was known about their physical and chemical stability during storage. The specific objectives were to: (i) prepare a freeze dried aqueous extract (FDAE), 20 % aqueous ethanol (Aq EtOH) extract and calcium alginate beads of the FDAE form of L. leonurus, (ii) characterize the extracts using parameters of select physical and chemical features and, (iii) determine the long-term stability of the extracts. It was hypothesised that the Aq EtOH extract would contain higher levels of chemical marker compounds (marrubiin and leonurine) than the FDAE and calcium alginate FDAE beads of L. leonurus and, that the calcium alginate FDAE beads would have greater stability (i.e. longer shelf-life) than the FDAE and the Aq EtOH extract. The three L. leonurus solid extracts were prepared using accepted published methods. For the physical characterization of the extracts, the organoleptic properties were determined using the natural senses (e.g. sight, smell, taste, etc.) and for chemical characterization, total phenol content (TPC; using the Folin-Ciocalteu reagent method), total flavonoid content (TFC; using aluminium chloride-methanol solution) and antioxidant activity (using the -diphenyl-2-picryl-hydrazyl (DPPH) assay). To establish the long-term stability of the preparations, encapsulated L. leonurus solid extracts was stored in sealed standard plastic containers at four conditions: (A), room temperature of 24 ˚C ± 5 ˚C; (B), fixed temperature of 30˚C ± 5 ˚C and (C), elevated temperature of 40˚C ± 5 ˚C for 6 months, and (D), accelerated stability test conditions of 40˚C ± 5 ˚C / 75 % RH for 4 weeks. Samples of the stored encapsulated preparations were collected periodically and assessed for changes in organoleptic properties, TPC, TFC, antioxidant activity levels and marker compound (i.e. marrubiin and leonurine) levels. The latter was determined by validated HPLC assay. Yields of 19.9, 12.82 and 10.7 % of FDAE, Aq EtOH extract and calcium alginate FDAE beads were obtained, respectively. Physically the calcium alginate beads contained less moisture (1.86 %) than the FDAE (3.77 %) and Aq EtOH (2.91 %). Chemically the FDAE, Aq EtOH extract and calcium alginate FDAE beads respectively had appreciable and similar TPC (i.e.7.86, 7.52 &, 6.94 mg GAE/g; p > 0.05; Anova) and TFC (i.e. 4.30, 4.47 & 3.67 mg QE/g; p > 0.05; Anova) levels, but variable amounts of marrubiin (i.e. 22.5, 17.5, and 0.4 ug/mg plant extract) and leonurine (i.e. 2.0, 1.4 and 0.7 ug/mg plant extract), respectively. The antioxidant activity levels were also different i.e. EC50 values of 7.71, 6.66 and 11.53 mg/mL (student t-test p-value of < 0.0001; ANOVA-test; p< 0.05) for the FDAE, Aq EtOH extract and calcium alginate FDAE beads, respectively. During storage (i.e. stability study) the L. leonurus solid extracts generally remained physically unaffected by temperature (i.e. no significant change in organoleptic features), but when exposed to humidity the FDAE and Aq EtOH extracts showed clear signs of physical degradation i.e. changed from being flaky powders to sticky melted masses, while the calcium alginate beads remained unchanged. Within 1 month storage at RT, 30 °C, 40 °C and 1 week at 40 °C / 75 % RH the TPC of the encapsulated FDAE decreased significantly by 61, 60, 58 and 52 %, respectively, that for the encapsulated Aq EtOH extract by 61, 54, 46 and 50 %, respectively, and for calcium alginate FDAE beads by 66, 71, 59 and 57 %, respectively. Using TPC as a stability parameter all three encapsulated extracts had very short shelf-lives ranging from 1.24 weeks (0.31 months) to 3.72 weeks (0.93 months). Under the same conditions and storage periods (i.e. 1 month & 1 week) the TFC of the encapsulated FDAE decreased significantly by 25, 25, 29 and 66 %, respectively, for encapsulated Aq EtOH extract by 26, 26, 23 and 70 %, respectively, and the calcium alginate FDAE beads by 55, 55, 52 and 64 %, respectively. The results obtained for TFC was thus similar to that obtained for the TPC data. Based on the TFC data all three encapsulated extracts had very short shelf-lives ranging, from 1.56 weeks (0.39 months) to 6.76 weeks (1.69 months). Under the same conditions and storage periods (i.e. 1 month & 1 week) as that used to determine TPC and TFC, the antioxidant activity of the extracts changed little, i.e. decreased by 0.2, 0.1, 0.8 and 2 %, respectively for FDAE, by 0.7 %, 1 %, 0.1 % and 5.3 %, respectively for the Aq EtOH and by 2, 2, 1.4 and 0.8 %, respectively for the calcium alginate FDAE beads. Moreover, based on antioxidant activity, all three encapsulated extracts had relatively long shelf-lives ranging from 15.6 weeks (3.9 months) to 22.4 weeks (5.6 months). Finally, the determination of the stability of the encapsulated L. leonurus extracts stored under stress conditions (i.e. 40 °C / 75 % RH) and based on marker compound levels was unresolved. Between the time of extract preparation and characterisation until start of the stability study the marrubiin levels in the FDAE, Aq. ETOH and calcium beads had decreased from 22.5, 17.5, and 0.4 ug/mg plant extract, respectively, to 0.30, 0.11, 0.30 μg/mg, respectively, and the leonurine levels from 2.0, 1.4 and 0.7 to 0.46, 0.38 and 0.09 μg/mg, respectively and was too low to conduct a meaningful stability study with the developed validated assay. Overall, all three the encapsulated L. leonurus solid extracts studied were clearly very unstable and did not have suitable long-term storage stability. The modification of the freeze-dried aqueous extract of L. leonurus into a calcium alginate bead form seemed to combat physical instability but did not improve the chemical instability of the aqueous extract. It is therefore recommended that the addition of excipients or other post extract modification (e.g. production of phytosomes) be explored to combat the hygroscopicity of L. leonurus FDAE and ultimately improve its overall product stability.

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