Os cálices do hibisco possuem uma grande quantidade de compostos bioativos responsáveis pela sua atividade antioxidante. O presente trabalho teve como objetivos a obtenção de extratos contendo esses compostos bioativos em solução aquosa com 2 % de ácido cítrico por extração assistida por micro-ondas (EAM) e o encapsulamento desses extratos por atomização e liofilização utilizando polidextrose (PD), proteína isolada do soro de leite (WPI) e a mistura destes na concentração de 10 %. Previamente foram estudados três métodos de extração, o primeiro usando somente EAM a 200, 300 e 700 W de potência, e tempos de 2, 5 e 8 minutos; o segundo consistiu de dois períodos, a extração aquosa ácida com tempos de 1, 2, 4, 6, 18 e 24 horas seguida de EAM nas potências de 200, 300 e 700 W; o terceiro consistiu de EAM seguida de extração aquosa ácida, nos mesmos tempos e potências citados para o segundo método. Os resultados indicaram que a melhor condição do primeiro método foi a 700 W e 8 min, do segundo método realizada a 6 horas de extração aquosa ácida, seguida de EAM a 700 W por 8 min e do terceiro método, EAM a 700 W por 8 min seguida de 6 horas de extração aquosa ácida. Quando os três métodos foram comparados, a melhor condição de extração foi aquela obtida no terceiro método: 1,63 mg delfinidina-3-sambubiosídeo · g-1; 29,62 mg EAG · g-1; 133,25 μmol ET · g-1 para antocianinas, fenólicos totais e atividade antioxidante por ABTS, respectivamente. Para avaliar o efeito da extração obtida somente por EAM, os extratos obtidos por extração exaustiva com metanol por 25 min e EAM a 700 W e 8 min foram quantificados por HPLC-DAD-ESI-MS/MS, sendo encontrados 13 compostos (6 ácidos fenólicos, 2 antocianinas e 5 flavonóides derivados da quercetina, kaempferol e miricetina). Os compostos fenólicos majoritários foram o ácido 3-cafeoilquínico (2,58 e 1,32 mg · g-1) e ácido 5-cafeoilquínico (1,71 e 0,90 mg · g-1) para extração exaustiva e EAM, respectivamente. Esse mesmo extrato (700 W e 8 min) foi encapsulado por atomização (160 °C) e liofilização (- 68 °C por 54 horas). Os pós obtidos foram avaliados quanto aos teores de compostos fenólicos totais, antocianinas monoméricas totais, atividade antioxidante (ABTS, DPPH e HRSA), medidas por análises espectrofotométricas, atividade de água, umidade, higroscopicidade, solubilidade, eficiência de encapsulação, cor, análise termogravimétrica, temperatura de transição vítrea, espectroscopia de infravermelho com transformada de Fourier (FTIR) e microestrutura (MEV). Os pós atomizados tiveram menor atividade de água (0,14 a 0,17), umidade (3,4 a 4,5 %), higroscopicidade (23,9 a 34,1 %), solubilidade (86 a 98,2 %) e eficiência de encapsulação (51,62 a 84,52 %) do que os pós liofilizados. Os resultados do FTIR mostraram que os encapsulantes não interagiram quimicamente, visto que não foram observados mudanças na frequência dos picos; as provas termogravimétricas indicaram que os pós apresentaram a mesma tendência nas perdas de massa. Na análise de microestrutura foi observado um melhor desempenho nas micropartículas atomizadas com PD, as quais mostraram partículas mais esféricas e sem tendência de atração e aderência entre si. Foram obtidas retenções de 38 a 77 % para antocianinas monoméricas totais, 42 a 89 % para compostos fenólicos totais, e entre 33 e 90 % para atividade antioxidante nos pós obtidos. O pó encapsulado liofilizado com 10 % de polidextrose mostrou uma maior retenção de antocianinas (77 %), atividade antioxidante por DDPH (90 %) e HRSA (74 %), entretanto com maior higroscopicidade (39,4 %). As provas aceleradas de estocagem (umidades relativas de 75 e 90 % em temperaturas de 40 e 60 °C) realizadas em todos os pós encapsulados, após 30 dias, indicaram que o tratamento liofilizado com 10 % de PD foi o que apresentou melhores resultados a essas condições, retendo 75 % dos compostos fenólicos, com atividades antioxidantes medidas por ABTS, DPPH e HRSA de 75, 90 e 74 %, respectivamente, existentes no extrato original. O pó obtido tem potencial para aplicação em alimentos, portanto, devido ao hibisco ser uma matriz com ampla composição de compostos bioativos. / The hibiscus calyces contend a high quantity of bioactive compounds responsible for their antioxidant activity. The present paper was aimed the production of extracts containing those bioactive compounds in acidified aqueous solution 2 % of citric acid by microwave assisted extraction (MAE) and the encapsulation of those extracts by spray drying and freeze-drying using polydextrose (PD), whey protein isolate (WPI) and their mixture in the concentration of 10 %. Previously three methods of extraction were studied, the first using only MAE at 200, 300 and 700 W of power, and times of 2, 5 and 8 minutes; the second consisted of two steps, the acid aqueous extraction with times of 1, 2, 4, 6, 18 and 24 hours followed by MAE at the powers of 200, 300 and 700 Watts; the third consisted of MAE followed by acid aqueous extraction, in the same times and powers mentioned for the second method. The results indicated that the best condition of the first method was 700 W and 8 minutes, the second method performed at 6 hours of acid aqueous extraction, followed by MAE at 700 W for 8 minutes and the third method, MAE at 700 W for 8 minutes followed by 6 hours of acid aqueous extraction. When the three methods are compared, the best condition of extraction was obtained in the third method: 1.63 mg delphinidin-3-sambubioside · g-1; 29.62 mg GAE · g-1; 133.25 μmol TE · g-1 for total monomeric anthocyanins, total phenolic compounds and antioxidant activity by ABTS, respectively. To evaluate the effect of the extraction obtained only by MAE, the extracts obtained by exhaustive extraction with methanol for 25 minutes and MAE at 700 W and 8 minutes were quantified by HPLC-DAD-ESI-MS/MS, was found 13 compounds (6 phenolic acids, 2 anthocyanins and 5 flavonoids derived from quercetin, kaempferol and myricetin). The phenolic compounds majorities were acid 3-caffeoylquinic (2.58 e 1.32 mg · g-1) and acid 5-caffeoylquinic (1.71 e 0.90 mg · g-1) for exhaustive extraction and MAE, respectively. That same extract (700 W and 8 minutes) was encapsulated by spray drying (160 ºC) and freeze-drying (- 68 °C for 54 hours). The obtained powders were evaluated about the levels of total phenolic compounds, total monomeric anthocyanins, antioxidant activity (ABTS, DPPH e HRSA), measured by spectrophotometric analysis, water activity, moisture, hygroscopicity, solubility, encapsulation efficiency, color, thermogravimetric analysis, glass transition temperature, Fourier transform infrared spectroscopy (FTIR) and microstructure (MEV). The spray dried powders had lower water activity (0.14 to 0.17), moisture (3.4 to 4.5 %), hygroscopicity (23.9 to 34.1 %), solubility (86 to 98.2 %) and encapsulation efficiency (51.62 to 84.52 %) than the freeze-dried powders. The results of FTIR showed that the encapsulants did not interact chemically, since changes were not observed on the frequency of the peaks; the thermogravimetric tests indicated that the powders presented the same tendency on the mass loss. On the microstructure analysis a better perform was observed on the spray dried microparticles with PD, which showed more spherical particles and with no tendency of attraction and adherence between them. Were obtained retentions of 38 to 77 % for total monomeric anthocyanins, 42 to 89 % for total phenolic compounds and between 33 and 90 % for antioxidant activity in the obtained powders. The encapsulated power by freeze-drying, with 10 % of polydextrose, was showed higher retention of anthocyanins (77 %), antioxidant activity by DDPH (90 %) and HRSA (74 %), however with higher hygroscopicity (39.4 %). The accelerated tests of storage (relative humidity of 75 and 90 % in temperatures of 40 and 60 ºC) performed in all the encapsulated powders, after 30 days, indicated that the freeze-drying treatment with 10 % of PD has the best behavior in those conditions, retaining 75 % of the phenolic compounds, with antioxidant activities measured by ABTS, DPPH and HRSA of 75, 90 and 74 %, respectively, present in the original extract. The obtained powder has potential for application in foods, therefore, due to the hibiscus being a matrix with ample composition of bioactive compounds.

A celulose das árvores do gênero Eucalyptus é um dos principais elementos de interesse econômico desse vegetal. Suas folhas, apesar de conter óleo essencial (OE), caracterizam-se como um subproduto da indústria de processamento de papel e celulose. Assim, pesquisas com relação à recuperação dessa biomassa tornam-se importantes, principalmente, do ponto de vista ambiental e econômico. Tradicionalmente, a extração de OEs ocorre pelo processo de hidrodestilação (HD), o qual necessita de longos tempos de extração. Visando superar essa restrição, a tecnologia de extração assistida por micro-ondas (Microwave Assisted Extraction - MAE) vem sendo desenvolvida e aplicada. O objetivo principal deste estudo foi avaliar o processo de extração de OE de folhas de eucalipto, empregando os métodos de extração HD e MAE. Para esse processo em escala de bancada, desenvolveu-se um aparato de extração por meio da adaptação de um forno micro-ondas doméstico. Inicialmente, analisou-se o rendimento de OE das matrizes de subprodutos de folhas de eucalipto das espécies Eucalyptus saligna, E. urohpylla e E. urophylla x globulus geradas a partir de uma indústria de celulose. Os resultados apontaram que a espécie E. urophylla x globulus apresentou maior teor de OE (2,16±0,02%), sendo a espécie escolhida para a aplicação da tecnologia MAE. Na segunda etapa do estudo, fez-se uma avaliação dos efeitos dos fatores do processo MAE, avaliando os fatores razão sólido:solvente (1:1; 1:1,5 e 1:2), potência do micro-ondas (680, 850 e 1.020 W) e tempo de extração total (20, 40, 60 min) no rendimento de OE. Desse modo, as condições ideais do processo foram determinadas como: razão sólido:solvente de 1:2, potência de 680 W e tempo de extração total de 60 minutos. Para essas condições, realizou-se o estudo cinético e modelagem matemática com a avaliação dos modelos de primeira ordem, segunda ordem, Peleg e Patricelli. No estudo cinético, o tempo total do processo MAE para a obtenção do rendimento de 1,8±0,1% foi apenas 60 minutos, tempo 57% inferior ao observado no método HD para igual rendimento (140 minutos). Dentre os modelos cinéticos estudados, o modelo de Patricelli foi o que apresentou melhor ajuste aos dados experimentais da extração HD (R² igual 0,9904 e RMSE igual 0,0016) e da extração MAE (R² igual 0,9962 e RMSE igual 0,0006). Por fim, as análises energéticas e de impacto ambiental também indicaram o método MAE como uma tecnologia mais ambientalmente amigável do que a HD, tornando-se atrativa para o setor industrial. Com base nos resultados obtidos, pode-se concluir que a extração de OE da matriz estudada proporcionou a reutilização de um subproduto industrial, sugerindo uma alternativa de exploração e agregando valor ao mesmo. / The cellulose from trees of the genus Eucalyptus is the main industrial product of this species. Its leaves, although containing essential oil (EO), are characterized as a by-product from the pulp and paper processing industry. Thus, researches about the recovery of this biomass are important, mainly from the environmental and ecological point of view. Traditionally, the extraction of EO occurs by hydrodistillation (HD), process that requires long extraction times. In order to overcome this restriction, microwave assisted extraction (MAE) has been developed and applied. The main objective of this study was to evaluate the extraction process of eucalyptus EO, using the HD and MAE methods. For this laboratory-scale process, an extraction apparatus was developed through the adaption of a domestic microwave oven. Initially, the yield of EO by-products of eucalyptus leaves of the species Eucalyptus saligna, E. urophylla and E. urophylla x globulus from a cellulose industry were analyzed. The results showed that the species E. urophylla x globulus presented the highest EO content (2.16 ± 0.02%), being the species chosen for the application of the MAE technology. In the second stage of the study, an evaluation of the effects of MAE process factors was performed, analyzing the factors ratio solid:solvent (1:1, 1:1,5 and 1:2), microwave power (680, 850 and 1.020 W) and total extraction time (20, 40, 60 min) in the EO yield. Thus, the ideal process conditions were determined as: ratio solid:solvent of 1:2, power of 680 W and total extraction time of 60 minutes. For these conditions, a kinetic study and a mathematical modeling were performed evaluating the first-order, second-order, Peleg and Patricelli models. In the kinetic study, the total time of the MAE process to obtain the yield of 1.8 ± 0.1% was only 60 minutes, 57% lower than the HD method for the same yield (140 min). Among the kinetic models studied, the Patricelli model presented the best fit to the experimental data of the HD extraction (R² equal to 0.9904 and RMSE equal to 0.0016) and MAE extraction (R² equal to 0.9962 and RMSE equal to 0.0006). Finally, the energy and environmental impact analyzes also indicated the MAE method more environmentally friendly than HD, being attractive for the industrial sector. Based on the results, it is possible to conclude that the extraction of EO from the studied matrix provided the reuse of an industrial by-product, suggesting an exploration alternative adding value to this residue.

Les organismes marins, dont les microalgues, constituent un champ d’investigation majeur pour la découverte de nouveaux médicaments anticancéreux. Pour mettre en évidence de nouvelles molécules anticancéreuses, nous avons adopté une démarche bioguidée sur des extraits de microalgues marines présentant une activité antiproliférative. Ce travail a conduit à l’isolement de la violaxanthine, pigment caroténoïde époxydé, et à la démonstration de son activité antiproliférative, cytotoxique, pro-apoptotique et pro-nécrotique sur la lignée cellulaire de cancer du sein MCF-7. Des caroténoïdes tels que la fucoxanthine sont déjà connus pour présenter une activité anticancéreuse liée à leur fonction époxyde. Cependant, cette étude est la première à montrer le potentiel de la violaxanthine.Afin d’isoler d’autres pigments microalgaux potentiellement anticancéreux, des méthodes de CLHP efficaces ont été développées pour leur analyse et leur purification. Puis, des méthodes classiques d’extraction de pigments issus de microalgues ont été comparées à des méthodes d’extraction innovantes. Cette étude a permis de montrer l’intérêt de la technologie micro-onde en termes d’efficacité et de rapidité pour l’extraction des pigments de microalgues frustulées (diatomées). Plus largement, ce travail confirme le potentiel des microalgues marines comme source de molécules anticancéreuses, et démontre l’intérêt de la technologie micro-onde pour l’extraction de molécules à activité biologique issues de produits naturels. / Marine organisms, including microalgae, constitute a major field of investigation for the discovery of new anticancer drugs. To obtain new anticancer compounds, we used a bio-guided methodology on microalgae extracts showing antiproliferative activity. This work led to the isolation of violaxanthin, an epoxycarotenoid pigment, and to the demonstration of its antiproliferative, cytotoxic, pro-apoptotic and pro-necrotic activity. Carotenoids such as fucoxanthin are already known to have anticancer activity related to the epoxide. However, this is the first study demonstrating the potential of violaxanthin.In order to isolate other pigments with anticancer activity , efficient HPLC methods were developed for their analysis and purification. Then, conventional methods of pigments extraction from microalgae were compared to innovative methods of extraction. This study demonstrates the interest of microwave technology in terms of efficiency and rapidity for the pigments extraction from frustulated microalgae (diatoms).To conclude, this work confirms the potential of marine microalgae as a source of anticancer drugs, and demonstrates the interest of microwave technology for the extraction of biologically active molecules from natural products.

Os cálices do hibisco possuem uma grande quantidade de compostos bioativos responsáveis pela sua atividade antioxidante. O presente trabalho teve como objetivos a obtenção de extratos contendo esses compostos bioativos em solução aquosa com 2 % de ácido cítrico por extração assistida por micro-ondas (EAM) e o encapsulamento desses extratos por atomização e liofilização utilizando polidextrose (PD), proteína isolada do soro de leite (WPI) e a mistura destes na concentração de 10 %. Previamente foram estudados três métodos de extração, o primeiro usando somente EAM a 200, 300 e 700 W de potência, e tempos de 2, 5 e 8 minutos; o segundo consistiu de dois períodos, a extração aquosa ácida com tempos de 1, 2, 4, 6, 18 e 24 horas seguida de EAM nas potências de 200, 300 e 700 W; o terceiro consistiu de EAM seguida de extração aquosa ácida, nos mesmos tempos e potências citados para o segundo método. Os resultados indicaram que a melhor condição do primeiro método foi a 700 W e 8 min, do segundo método realizada a 6 horas de extração aquosa ácida, seguida de EAM a 700 W por 8 min e do terceiro método, EAM a 700 W por 8 min seguida de 6 horas de extração aquosa ácida. Quando os três métodos foram comparados, a melhor condição de extração foi aquela obtida no terceiro método: 1,63 mg delfinidina-3-sambubiosídeo · g-1; 29,62 mg EAG · g-1; 133,25 μmol ET · g-1 para antocianinas, fenólicos totais e atividade antioxidante por ABTS, respectivamente. Para avaliar o efeito da extração obtida somente por EAM, os extratos obtidos por extração exaustiva com metanol por 25 min e EAM a 700 W e 8 min foram quantificados por HPLC-DAD-ESI-MS/MS, sendo encontrados 13 compostos (6 ácidos fenólicos, 2 antocianinas e 5 flavonóides derivados da quercetina, kaempferol e miricetina). Os compostos fenólicos majoritários foram o ácido 3-cafeoilquínico (2,58 e 1,32 mg · g-1) e ácido 5-cafeoilquínico (1,71 e 0,90 mg · g-1) para extração exaustiva e EAM, respectivamente. Esse mesmo extrato (700 W e 8 min) foi encapsulado por atomização (160 °C) e liofilização (- 68 °C por 54 horas). Os pós obtidos foram avaliados quanto aos teores de compostos fenólicos totais, antocianinas monoméricas totais, atividade antioxidante (ABTS, DPPH e HRSA), medidas por análises espectrofotométricas, atividade de água, umidade, higroscopicidade, solubilidade, eficiência de encapsulação, cor, análise termogravimétrica, temperatura de transição vítrea, espectroscopia de infravermelho com transformada de Fourier (FTIR) e microestrutura (MEV). Os pós atomizados tiveram menor atividade de água (0,14 a 0,17), umidade (3,4 a 4,5 %), higroscopicidade (23,9 a 34,1 %), solubilidade (86 a 98,2 %) e eficiência de encapsulação (51,62 a 84,52 %) do que os pós liofilizados. Os resultados do FTIR mostraram que os encapsulantes não interagiram quimicamente, visto que não foram observados mudanças na frequência dos picos; as provas termogravimétricas indicaram que os pós apresentaram a mesma tendência nas perdas de massa. Na análise de microestrutura foi observado um melhor desempenho nas micropartículas atomizadas com PD, as quais mostraram partículas mais esféricas e sem tendência de atração e aderência entre si. Foram obtidas retenções de 38 a 77 % para antocianinas monoméricas totais, 42 a 89 % para compostos fenólicos totais, e entre 33 e 90 % para atividade antioxidante nos pós obtidos. O pó encapsulado liofilizado com 10 % de polidextrose mostrou uma maior retenção de antocianinas (77 %), atividade antioxidante por DDPH (90 %) e HRSA (74 %), entretanto com maior higroscopicidade (39,4 %). As provas aceleradas de estocagem (umidades relativas de 75 e 90 % em temperaturas de 40 e 60 °C) realizadas em todos os pós encapsulados, após 30 dias, indicaram que o tratamento liofilizado com 10 % de PD foi o que apresentou melhores resultados a essas condições, retendo 75 % dos compostos fenólicos, com atividades antioxidantes medidas por ABTS, DPPH e HRSA de 75, 90 e 74 %, respectivamente, existentes no extrato original. O pó obtido tem potencial para aplicação em alimentos, portanto, devido ao hibisco ser uma matriz com ampla composição de compostos bioativos. / The hibiscus calyces contend a high quantity of bioactive compounds responsible for their antioxidant activity. The present paper was aimed the production of extracts containing those bioactive compounds in acidified aqueous solution 2 % of citric acid by microwave assisted extraction (MAE) and the encapsulation of those extracts by spray drying and freeze-drying using polydextrose (PD), whey protein isolate (WPI) and their mixture in the concentration of 10 %. Previously three methods of extraction were studied, the first using only MAE at 200, 300 and 700 W of power, and times of 2, 5 and 8 minutes; the second consisted of two steps, the acid aqueous extraction with times of 1, 2, 4, 6, 18 and 24 hours followed by MAE at the powers of 200, 300 and 700 Watts; the third consisted of MAE followed by acid aqueous extraction, in the same times and powers mentioned for the second method. The results indicated that the best condition of the first method was 700 W and 8 minutes, the second method performed at 6 hours of acid aqueous extraction, followed by MAE at 700 W for 8 minutes and the third method, MAE at 700 W for 8 minutes followed by 6 hours of acid aqueous extraction. When the three methods are compared, the best condition of extraction was obtained in the third method: 1.63 mg delphinidin-3-sambubioside · g-1; 29.62 mg GAE · g-1; 133.25 μmol TE · g-1 for total monomeric anthocyanins, total phenolic compounds and antioxidant activity by ABTS, respectively. To evaluate the effect of the extraction obtained only by MAE, the extracts obtained by exhaustive extraction with methanol for 25 minutes and MAE at 700 W and 8 minutes were quantified by HPLC-DAD-ESI-MS/MS, was found 13 compounds (6 phenolic acids, 2 anthocyanins and 5 flavonoids derived from quercetin, kaempferol and myricetin). The phenolic compounds majorities were acid 3-caffeoylquinic (2.58 e 1.32 mg · g-1) and acid 5-caffeoylquinic (1.71 e 0.90 mg · g-1) for exhaustive extraction and MAE, respectively. That same extract (700 W and 8 minutes) was encapsulated by spray drying (160 ºC) and freeze-drying (- 68 °C for 54 hours). The obtained powders were evaluated about the levels of total phenolic compounds, total monomeric anthocyanins, antioxidant activity (ABTS, DPPH e HRSA), measured by spectrophotometric analysis, water activity, moisture, hygroscopicity, solubility, encapsulation efficiency, color, thermogravimetric analysis, glass transition temperature, Fourier transform infrared spectroscopy (FTIR) and microstructure (MEV). The spray dried powders had lower water activity (0.14 to 0.17), moisture (3.4 to 4.5 %), hygroscopicity (23.9 to 34.1 %), solubility (86 to 98.2 %) and encapsulation efficiency (51.62 to 84.52 %) than the freeze-dried powders. The results of FTIR showed that the encapsulants did not interact chemically, since changes were not observed on the frequency of the peaks; the thermogravimetric tests indicated that the powders presented the same tendency on the mass loss. On the microstructure analysis a better perform was observed on the spray dried microparticles with PD, which showed more spherical particles and with no tendency of attraction and adherence between them. Were obtained retentions of 38 to 77 % for total monomeric anthocyanins, 42 to 89 % for total phenolic compounds and between 33 and 90 % for antioxidant activity in the obtained powders. The encapsulated power by freeze-drying, with 10 % of polydextrose, was showed higher retention of anthocyanins (77 %), antioxidant activity by DDPH (90 %) and HRSA (74 %), however with higher hygroscopicity (39.4 %). The accelerated tests of storage (relative humidity of 75 and 90 % in temperatures of 40 and 60 ºC) performed in all the encapsulated powders, after 30 days, indicated that the freeze-drying treatment with 10 % of PD has the best behavior in those conditions, retaining 75 % of the phenolic compounds, with antioxidant activities measured by ABTS, DPPH and HRSA of 75, 90 and 74 %, respectively, present in the original extract. The obtained powder has potential for application in foods, therefore, due to the hibiscus being a matrix with ample composition of bioactive compounds.

Os cálices do hibisco possuem uma grande quantidade de compostos bioativos responsáveis pela sua atividade antioxidante. O presente trabalho teve como objetivos a obtenção de extratos contendo esses compostos bioativos em solução aquosa com 2 % de ácido cítrico por extração assistida por micro-ondas (EAM) e o encapsulamento desses extratos por atomização e liofilização utilizando polidextrose (PD), proteína isolada do soro de leite (WPI) e a mistura destes na concentração de 10 %. Previamente foram estudados três métodos de extração, o primeiro usando somente EAM a 200, 300 e 700 W de potência, e tempos de 2, 5 e 8 minutos; o segundo consistiu de dois períodos, a extração aquosa ácida com tempos de 1, 2, 4, 6, 18 e 24 horas seguida de EAM nas potências de 200, 300 e 700 W; o terceiro consistiu de EAM seguida de extração aquosa ácida, nos mesmos tempos e potências citados para o segundo método. Os resultados indicaram que a melhor condição do primeiro método foi a 700 W e 8 min, do segundo método realizada a 6 horas de extração aquosa ácida, seguida de EAM a 700 W por 8 min e do terceiro método, EAM a 700 W por 8 min seguida de 6 horas de extração aquosa ácida. Quando os três métodos foram comparados, a melhor condição de extração foi aquela obtida no terceiro método: 1,63 mg delfinidina-3-sambubiosídeo · g-1; 29,62 mg EAG · g-1; 133,25 μmol ET · g-1 para antocianinas, fenólicos totais e atividade antioxidante por ABTS, respectivamente. Para avaliar o efeito da extração obtida somente por EAM, os extratos obtidos por extração exaustiva com metanol por 25 min e EAM a 700 W e 8 min foram quantificados por HPLC-DAD-ESI-MS/MS, sendo encontrados 13 compostos (6 ácidos fenólicos, 2 antocianinas e 5 flavonóides derivados da quercetina, kaempferol e miricetina). Os compostos fenólicos majoritários foram o ácido 3-cafeoilquínico (2,58 e 1,32 mg · g-1) e ácido 5-cafeoilquínico (1,71 e 0,90 mg · g-1) para extração exaustiva e EAM, respectivamente. Esse mesmo extrato (700 W e 8 min) foi encapsulado por atomização (160 °C) e liofilização (- 68 °C por 54 horas). Os pós obtidos foram avaliados quanto aos teores de compostos fenólicos totais, antocianinas monoméricas totais, atividade antioxidante (ABTS, DPPH e HRSA), medidas por análises espectrofotométricas, atividade de água, umidade, higroscopicidade, solubilidade, eficiência de encapsulação, cor, análise termogravimétrica, temperatura de transição vítrea, espectroscopia de infravermelho com transformada de Fourier (FTIR) e microestrutura (MEV). Os pós atomizados tiveram menor atividade de água (0,14 a 0,17), umidade (3,4 a 4,5 %), higroscopicidade (23,9 a 34,1 %), solubilidade (86 a 98,2 %) e eficiência de encapsulação (51,62 a 84,52 %) do que os pós liofilizados. Os resultados do FTIR mostraram que os encapsulantes não interagiram quimicamente, visto que não foram observados mudanças na frequência dos picos; as provas termogravimétricas indicaram que os pós apresentaram a mesma tendência nas perdas de massa. Na análise de microestrutura foi observado um melhor desempenho nas micropartículas atomizadas com PD, as quais mostraram partículas mais esféricas e sem tendência de atração e aderência entre si. Foram obtidas retenções de 38 a 77 % para antocianinas monoméricas totais, 42 a 89 % para compostos fenólicos totais, e entre 33 e 90 % para atividade antioxidante nos pós obtidos. O pó encapsulado liofilizado com 10 % de polidextrose mostrou uma maior retenção de antocianinas (77 %), atividade antioxidante por DDPH (90 %) e HRSA (74 %), entretanto com maior higroscopicidade (39,4 %). As provas aceleradas de estocagem (umidades relativas de 75 e 90 % em temperaturas de 40 e 60 °C) realizadas em todos os pós encapsulados, após 30 dias, indicaram que o tratamento liofilizado com 10 % de PD foi o que apresentou melhores resultados a essas condições, retendo 75 % dos compostos fenólicos, com atividades antioxidantes medidas por ABTS, DPPH e HRSA de 75, 90 e 74 %, respectivamente, existentes no extrato original. O pó obtido tem potencial para aplicação em alimentos, portanto, devido ao hibisco ser uma matriz com ampla composição de compostos bioativos. / The hibiscus calyces contend a high quantity of bioactive compounds responsible for their antioxidant activity. The present paper was aimed the production of extracts containing those bioactive compounds in acidified aqueous solution 2 % of citric acid by microwave assisted extraction (MAE) and the encapsulation of those extracts by spray drying and freeze-drying using polydextrose (PD), whey protein isolate (WPI) and their mixture in the concentration of 10 %. Previously three methods of extraction were studied, the first using only MAE at 200, 300 and 700 W of power, and times of 2, 5 and 8 minutes; the second consisted of two steps, the acid aqueous extraction with times of 1, 2, 4, 6, 18 and 24 hours followed by MAE at the powers of 200, 300 and 700 Watts; the third consisted of MAE followed by acid aqueous extraction, in the same times and powers mentioned for the second method. The results indicated that the best condition of the first method was 700 W and 8 minutes, the second method performed at 6 hours of acid aqueous extraction, followed by MAE at 700 W for 8 minutes and the third method, MAE at 700 W for 8 minutes followed by 6 hours of acid aqueous extraction. When the three methods are compared, the best condition of extraction was obtained in the third method: 1.63 mg delphinidin-3-sambubioside · g-1; 29.62 mg GAE · g-1; 133.25 μmol TE · g-1 for total monomeric anthocyanins, total phenolic compounds and antioxidant activity by ABTS, respectively. To evaluate the effect of the extraction obtained only by MAE, the extracts obtained by exhaustive extraction with methanol for 25 minutes and MAE at 700 W and 8 minutes were quantified by HPLC-DAD-ESI-MS/MS, was found 13 compounds (6 phenolic acids, 2 anthocyanins and 5 flavonoids derived from quercetin, kaempferol and myricetin). The phenolic compounds majorities were acid 3-caffeoylquinic (2.58 e 1.32 mg · g-1) and acid 5-caffeoylquinic (1.71 e 0.90 mg · g-1) for exhaustive extraction and MAE, respectively. That same extract (700 W and 8 minutes) was encapsulated by spray drying (160 ºC) and freeze-drying (- 68 °C for 54 hours). The obtained powders were evaluated about the levels of total phenolic compounds, total monomeric anthocyanins, antioxidant activity (ABTS, DPPH e HRSA), measured by spectrophotometric analysis, water activity, moisture, hygroscopicity, solubility, encapsulation efficiency, color, thermogravimetric analysis, glass transition temperature, Fourier transform infrared spectroscopy (FTIR) and microstructure (MEV). The spray dried powders had lower water activity (0.14 to 0.17), moisture (3.4 to 4.5 %), hygroscopicity (23.9 to 34.1 %), solubility (86 to 98.2 %) and encapsulation efficiency (51.62 to 84.52 %) than the freeze-dried powders. The results of FTIR showed that the encapsulants did not interact chemically, since changes were not observed on the frequency of the peaks; the thermogravimetric tests indicated that the powders presented the same tendency on the mass loss. On the microstructure analysis a better perform was observed on the spray dried microparticles with PD, which showed more spherical particles and with no tendency of attraction and adherence between them. Were obtained retentions of 38 to 77 % for total monomeric anthocyanins, 42 to 89 % for total phenolic compounds and between 33 and 90 % for antioxidant activity in the obtained powders. The encapsulated power by freeze-drying, with 10 % of polydextrose, was showed higher retention of anthocyanins (77 %), antioxidant activity by DDPH (90 %) and HRSA (74 %), however with higher hygroscopicity (39.4 %). The accelerated tests of storage (relative humidity of 75 and 90 % in temperatures of 40 and 60 ºC) performed in all the encapsulated powders, after 30 days, indicated that the freeze-drying treatment with 10 % of PD has the best behavior in those conditions, retaining 75 % of the phenolic compounds, with antioxidant activities measured by ABTS, DPPH and HRSA of 75, 90 and 74 %, respectively, present in the original extract. The obtained powder has potential for application in foods, therefore, due to the hibiscus being a matrix with ample composition of bioactive compounds.

A celulose das árvores do gênero Eucalyptus é um dos principais elementos de interesse econômico desse vegetal. Suas folhas, apesar de conter óleo essencial (OE), caracterizam-se como um subproduto da indústria de processamento de papel e celulose. Assim, pesquisas com relação à recuperação dessa biomassa tornam-se importantes, principalmente, do ponto de vista ambiental e econômico. Tradicionalmente, a extração de OEs ocorre pelo processo de hidrodestilação (HD), o qual necessita de longos tempos de extração. Visando superar essa restrição, a tecnologia de extração assistida por micro-ondas (Microwave Assisted Extraction - MAE) vem sendo desenvolvida e aplicada. O objetivo principal deste estudo foi avaliar o processo de extração de OE de folhas de eucalipto, empregando os métodos de extração HD e MAE. Para esse processo em escala de bancada, desenvolveu-se um aparato de extração por meio da adaptação de um forno micro-ondas doméstico. Inicialmente, analisou-se o rendimento de OE das matrizes de subprodutos de folhas de eucalipto das espécies Eucalyptus saligna, E. urohpylla e E. urophylla x globulus geradas a partir de uma indústria de celulose. Os resultados apontaram que a espécie E. urophylla x globulus apresentou maior teor de OE (2,16±0,02%), sendo a espécie escolhida para a aplicação da tecnologia MAE. Na segunda etapa do estudo, fez-se uma avaliação dos efeitos dos fatores do processo MAE, avaliando os fatores razão sólido:solvente (1:1; 1:1,5 e 1:2), potência do micro-ondas (680, 850 e 1.020 W) e tempo de extração total (20, 40, 60 min) no rendimento de OE. Desse modo, as condições ideais do processo foram determinadas como: razão sólido:solvente de 1:2, potência de 680 W e tempo de extração total de 60 minutos. Para essas condições, realizou-se o estudo cinético e modelagem matemática com a avaliação dos modelos de primeira ordem, segunda ordem, Peleg e Patricelli. No estudo cinético, o tempo total do processo MAE para a obtenção do rendimento de 1,8±0,1% foi apenas 60 minutos, tempo 57% inferior ao observado no método HD para igual rendimento (140 minutos). Dentre os modelos cinéticos estudados, o modelo de Patricelli foi o que apresentou melhor ajuste aos dados experimentais da extração HD (R² igual 0,9904 e RMSE igual 0,0016) e da extração MAE (R² igual 0,9962 e RMSE igual 0,0006). Por fim, as análises energéticas e de impacto ambiental também indicaram o método MAE como uma tecnologia mais ambientalmente amigável do que a HD, tornando-se atrativa para o setor industrial. Com base nos resultados obtidos, pode-se concluir que a extração de OE da matriz estudada proporcionou a reutilização de um subproduto industrial, sugerindo uma alternativa de exploração e agregando valor ao mesmo. / The cellulose from trees of the genus Eucalyptus is the main industrial product of this species. Its leaves, although containing essential oil (EO), are characterized as a by-product from the pulp and paper processing industry. Thus, researches about the recovery of this biomass are important, mainly from the environmental and ecological point of view. Traditionally, the extraction of EO occurs by hydrodistillation (HD), process that requires long extraction times. In order to overcome this restriction, microwave assisted extraction (MAE) has been developed and applied. The main objective of this study was to evaluate the extraction process of eucalyptus EO, using the HD and MAE methods. For this laboratory-scale process, an extraction apparatus was developed through the adaption of a domestic microwave oven. Initially, the yield of EO by-products of eucalyptus leaves of the species Eucalyptus saligna, E. urophylla and E. urophylla x globulus from a cellulose industry were analyzed. The results showed that the species E. urophylla x globulus presented the highest EO content (2.16 ± 0.02%), being the species chosen for the application of the MAE technology. In the second stage of the study, an evaluation of the effects of MAE process factors was performed, analyzing the factors ratio solid:solvent (1:1, 1:1,5 and 1:2), microwave power (680, 850 and 1.020 W) and total extraction time (20, 40, 60 min) in the EO yield. Thus, the ideal process conditions were determined as: ratio solid:solvent of 1:2, power of 680 W and total extraction time of 60 minutes. For these conditions, a kinetic study and a mathematical modeling were performed evaluating the first-order, second-order, Peleg and Patricelli models. In the kinetic study, the total time of the MAE process to obtain the yield of 1.8 ± 0.1% was only 60 minutes, 57% lower than the HD method for the same yield (140 min). Among the kinetic models studied, the Patricelli model presented the best fit to the experimental data of the HD extraction (R² equal to 0.9904 and RMSE equal to 0.0016) and MAE extraction (R² equal to 0.9962 and RMSE equal to 0.0006). Finally, the energy and environmental impact analyzes also indicated the MAE method more environmentally friendly than HD, being attractive for the industrial sector. Based on the results, it is possible to conclude that the extraction of EO from the studied matrix provided the reuse of an industrial by-product, suggesting an exploration alternative adding value to this residue.

Lignin är, med undantag för cellulosa, den av de naturliga polymererna det finns mest av på jorden och den ledande källan till fenolföreningar. De träväxterna som existerar idag, innehåller ca 30 % av just denna biopolymer. Lignin har länge ansetts vara svår att utnyttja i materialapplikationer, i jämförelse med de polymererna som existerar i lignocellulosa biomassa, nämligen cellulosa och hemicellulosa. Konventionella metoder som innefattar lignin-extraktion leder ofta till strukturell skada på polymeren, men också, blir ofta resultatet en försämrad, modifierad produkt med få användningsområden. Mikrovågsextraktion är en nyare process som är både effektiv och selektiv. I denna rapport har tre typer av lignin-innehållande växter använts som biomass-råvara, nämligen barrträ, lövträ och halm för att utforska möjligheterna att isolera lignin med mikrovågs-assisterad extraktion. Utspädd svavelsyra har använts som lösningsmedel i denna extraktion. Olika kombinationer av parametrar har använts med avseende på temperatur (180-200 °C), processtid (5-20 minuter) samt koncentration av svavelsyra (0.2 M och 1 M). Syftet med extraktionen var att avlägsna cellulosa samt hemicellulosa. Även förbehandling av biomassan har undersökts med fokus på malningsprocessen och torkningsförhållandena. Den kvarvarande fasta fasen, förhoppningsvis syra-olösligt lignin, har analyserats med FTIR, TGA, HSQC-, 31P- samt 1H-NMR. Den lösliga fasen (potentiellt syra-lösligt lignin samt polysackarider) har analyserats med hjälp av 13C-NMR. Lignin, utvunnet från tall (mjukträ) vid 190 °C, 0.2 M svavelsyra under 15 respektive 20 minuter visade sig ha de mest önskvärda egenskaperna (högre lignin-innehåll). För provet med den lägre processtiden användes olika tillvägagångssätt för att utvinna mer produkt per mikrovågsextraktion vilket ledde till sämre resultat. På grund av tidsbegränsningen av arbetet, blandades de nya proven för att uppnå en lämplig mängd lignin för att fortsätta utvärdera de möjliga material-applikationerna. Det utvunna ligninet acetylerades för att förhoppningsvis förbättra kompatibilitet med den mer hydrofoba polymeren polylaktid (PLA). Därefter, blandades lignintyperna med PLA var för sig till 10 vikt% vardera. Nästa steg involverade filament-extrudering för att förbereda materialen för 3D-printing. Dessvärre, lyckades endast ett prov med en enhetlig extrudering, nämligen ligninet från den kortare mikrovågsprocessen, PLA/Lignin15. PLA extruderades för att kunna jämföra egenskaperna med lignin/PLA blandningen. Båda materialen 3D printades till en hundbenssliknande form och undersöktes med dragprovning. Resultatet var ett material med 10 vikt% lignin blandat med PLA med en lägre töjning vid brott (%) och med liknande maximal dragspänning (MPa) än PLA. / Lignin is, second after cellulose, the most abundant natural polymer on earth and the leading natural source of phenolic compounds. Woody plants that exist today consist of ∼30 % of this biopolymer. Lignin has long been seen as a difficult material to utilize in material applications in comparison to the other two main polymers existing in woody biomass- cellulose and hemicellulose. Conventional methods of extraction of lignin often result in a structurally damaged polymer, often highly degraded, modified or condensed lignin with finite usages. Microwave extraction is a more novel process contributing to efficient and selective processing. Softwood, hardwood and straw have been utilized as biomass sources in this study to evaluate the possibility of isolating lignin by microwave-assisted extraction. Diluted sulphuric acid was used as solvent in this extraction. Different parameters have been investigated- a temperature range of 180 °C-200 °C, a reaction duration varying from 5-20 minutes and a concentration of sulphuric acid of 0.2 M or 1 M. The aim of the extraction was to remove cellulose and hemicellulose. The remaining solid phase, expectantly lignin, was  analyzed by FTIR, TGA, HSQC-, 31P-, and 1H-NMR. The liquid phase after extraction was analyzed by 13C-NMR. The samples with the more favorable properties (higher lignin content) appeared to be lignin extracted from Pine (Softwood) with the processing temperature of 190 °C with 0.2 M sulphuric acid with a time of 15 and 20 minutes. For the sample with the lower processing time different approaches were used to achieve more product per microwave extraction but this led to inferior results. Due to the limit of time, the new samples were blended to achieve an appropriate amount of lignin for further evaluation in material applications. More product from the lignin with the longer extraction time was also needed and resulted in more similar lignin properties. The goal was to blend the most suitable lignin (the sample with the more distinct lignin structure /highest lignin content based on the analysis) with PLA. The extracted lignin was acetylated to hopefully achieve better compatibility with the more hydrophobic PLA. Thereafter, filament extrusion took place prior to 3D printing. Extrusion of PLA with the modified lignin sample with a processing time of 20 minutes failed (PLA/Lignin19). The other blend on the other hand, PLA/Lignin15, was more successful leading to successful filament extrusion and 3D printing being performed. Also, neat PLA was extruded successfully and 3D printed for comparison in tensile testing. The result was a material with 10 wt. % of lignin incorporated in PLA. The material had a decrease in elongation at break (%) but similar tensile strength (MPa) compared to PLA.

Nine Virginia soybeans grown in a single location were compared for their antioxidant properties and isoflavone profiles. The extracts were evaluated for their total phenolic contents (TPC), Oxygen Radical Absorbance Capacity (ORAC), and DPPH™ radical scavenging activities. In order to evaluate efficient preparation methods for soybean antioxidants, three Virginia-grown soybeans were extracted using different extraction strategies. The extraction techniques included soxhlet extraction, conventional solvent extraction, and ultrasonic-assisted extraction (UAE) with 5 different common solvent systems including 50% and 80% aqueous acetone, 50 and 70% aqueous ethanol, and 80% aqueous methanol. The TPC in the soybean extracts and isoflavone compositions were significantly different among cultivars. Malonylgenistin was the major isoflavone in all soybean seeds, accounting for 75-83% of the total measured isoflavones. The V01-4937 variety had the highest total isoflavone and malonylgenistin contents, followed by V03-5794. The antioxidant activities of the soybean extracts were also significantly different. Overall, the V01-4937 soybean was the variety that stood out from the other tested Virginia soybeans because it had the highest TPC, ORAC value, and isoflavone contents as well as the second highest DPPH™ scavenging activity. Ultrasonic treatment improved the extraction of soybean phenolics by more than 50% compared to solvent alone. The UAE with 50% aqueous acetone was the most efficient for extraction of phenolic compounds in the soybean seeds. The conventional and UAE with 70% aqueous ethanol extracts had the highest ORAC values, while the soxhlet methanol extracts had the highest DPPH™ radical scavenging activities. Our results suggest that different extraction technologies have a remarkable effect on soybean antioxidant estimation and the UAE is more appropriate for soybean phenolic extraction because it is less time and solvent consuming than the conventional solvent and soxhlet extractions. The V01-4937 soybean with the highest TPC was evaluated for its antioxidant activity and isoflavone contents in an in vitro digestive system. After gastrointestinal digestion, soybean extracts contained higher TPC and ORAC values than cooked soybean (before digestion) but they were relatively low in DPPH™ radical scavenging capacity. The glucosides, daidzin, genistin, and malonylgenistin showed stability during simulated digestion with 83.3 %, 59.4 %, and 10.7 % recovery, respectively. Aglycones, including daidzein and genistein, were recovered at 37 % and 73.7 %, respectively, after in vitro digestion. In this study, daidzin was the most stable and bioaccessible isoflavone determined using the in vitro digestive system. Among the aglycones, genistein was more stable and bioaccessible than daidzein after digestion. In conclusion, soybean antioxidant activities were different among cultivars and efficient extraction for TPC was found using UAE with 50% aqueous acetone. Furthermore, antioxidant activities were stable during digestion and genistein, within aglycones tested, was the most stable and bioaccessible compound following in vitro digestion. This information may provide manufacturers or researchers information required to develop food or nutraceutical products processed for better bioaccessibility of soybean bioactive components. / Ph. D.

Experimental data are presented for the first time in support of a theoretical model of band broadening proposed by Blumberg (1997). This model addresses the effects of the compressibility of the mobile phase in gas chromatography and presents an equation derived from only two mutually independent variables. Solutions of decane and tridecane in hexane were analyzed at pressures ranging from 15 to 150 psi. Six different columns were used that varied in length, internal diameter and film thickness. Theoretical plate heights were obtained from this data and plotted versus the average linear carrier gas velocity (Golay type plots). These plots showed that at high pressures the Blumberg model fit the experimental data statistically significantly better than the earlier model proposed by Golay. The Blumberg model also accurately predicts the relationship between the optimum linear carrier gas velocity and the temperature. The second part of this work explores the scope and limitations of fast temperature programming in the fast GC analyses of various sample types. These samples included polycyclic aromatic hydrocarbons (PAHs), hydrocarbons and food samples. Programming rates of up to 1200° C/min were used. These fast programming rates were obtained by using "flash"â ¢ temperature programming, controlled by resistive heating of a metal tube that enclosed a capillary column. The precision of peak data was found to be good, less than 5% for peak areas and 4% for retention times. However, a slight, but statistically significant decrease in peak areas was seen above programming rates of 240° C/min. Microwave assisted extraction (MAE) was used to extract 2,6-di-(tert-butyl)-4-methylphenol, BHT, from chewing gum and breakfast cereal. The extraction was followed by a fast GC analysis (less than 4 minutes) using "flash"â ¢ temperature programming. MAE reduced the sample preparation time, from hours to minutes, and consequently reduced, the total analysis time. Extraction times longer than 5 minutes gave decreased recoveries of BHT. / Ph. D.

By addressing new sample preparation techniques, the U.S. Environmental Protection Agency (EPA) has recently implemented research programs to reduce or abolish laboratory pollution. In the work reported here, EPA Method 8270, established for Priority Pollutant Organics, will be evaluated by both Soxhlet and microwave-assisted extraction (MAE) for two classifications of compounds. The common procedure for sample preparation of solids is Soxhlet extraction. This is a lengthy operation and uses abundant solvent volumes. With ever changing times, the new technology of MAE is surfacing. This technique uses far less solvent and sample preparation times are greatly reduced. The work reported here compares the recoveries of phenolic and polynuclear aromatic compounds for both Soxhlet and closed-vessel MAE. / Master of Science