• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 41
  • 28
  • 4
  • 3
  • 1
  • 1
  • 1
  • Tagged with
  • 93
  • 20
  • 16
  • 15
  • 12
  • 10
  • 10
  • 9
  • 8
  • 8
  • 8
  • 8
  • 8
  • 7
  • 7
  • 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.
21

Avaliação da composição e da capacidade antioxidante "in vivo" e "in vitro"de antocianinas da casca de jabuticaba (Myrciaria jaboticaba (Vell.) Berg) liofilizada em ratos Wistar / Evaluation of composition and antioxidant capacity in vivo and in vitro anthocyanins in freeze-dried jaboticaba peel (Myrciaria jaboticaba (Vell.) Berg) in rats

Leite, Alice Vieira 16 August 2018 (has links)
Orientador: Mário Roberto Maróstica Júnior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-16T13:28:38Z (GMT). No. of bitstreams: 1 Leite_AliceVieira_M.pdf: 971111 bytes, checksum: 075888bf78f40ee6ae18cdf0e3fb131a (MD5) Previous issue date: 2010 / Resumo: O objetivo do presente estudo foi avaliar a produção de casca de jabuticaba em pó, sua composição de antocianinas e efeito antioxidante em animais de laboratório. Muitas frutas tropicais são ricas em antocianinas e existem poucos dados disponíveis sobre a caracterização e quantificação destas antocianinas. A identificação e quantificação de antocianinas de casca de jabuticaba liofilizada foram realizadas por HPLC-PDA e HPLC-ESI-MS/MS e revelaram a presença de dois compostos, delfinidina-3-glicosídeo e cianidina-3- glicosídeo (635,3 e 1964 mg/100 de peso seco), respectivamente. Para as análises do potencial antioxidante foram utilizados os ensaios de ORAC, DPPH e ABTS. Para estes ensaios foram encontrados os seguintes valores, respectivamente, 25514,25±3037,24 YMTEAC.g-1, 45,38 Yg.ml-1, 9457,74±54,29 YMTEAC.g-1. Foram quantificados também os fenólicos totais por Folin-Ciocalteau, e encontrado 556,28±20,37 gGAEb.kg-1 .Neste estudo, a casca de jabuticaba liofilizada mostrou uma grande capacidade antioxidante comprovada por todos os métodos antioxidantes analisados, pela quantidade de compostos fenólicos encontrada e principalmente pela concentração de cianidina-3-glicosídeo e delfinidina-3- glicosídeo. Diante dos dados descritos acima, o efeito antioxidante da ingestão de pó casca de jabuticaba liofilizada no plasma de ratos foi investigado em dois experimentos. No primeiro foi realizado um teste de cinética de absorção, no qual trinta e cinco ratos machos, divididos em 5 grupos, receberam por gavagem 7 mg de antocianinas/ 100 g de peso. A coleta de sangue foi realizada nos tempos 0, 30, 60 e 120 minutos. O potencial antioxidante foi quantificado no plasma por ORAC e TEAC. Neste experimento não ocorreu diferença significativa no potencial antioxidante plasmático quando comparados os diversos tempos. No segundo experimento, 40 ratos machos foram divididos em 4 grupos que consumiram, respectivamente, 0, 1, 2 e 4% de pó de casca de jabuticaba liofilizada acrescido a dieta. Foi observado um aumento no potencial antioxidante plasmático (1.7 vezes pelo método de TEAC e 1.3 vezes por ORAC), porém a concentração de 4% não apresentou efeito antioxidante. A partir dos resultados do potencial antioxidante in vivo, e diante do fato de que a ingestão de uma dieta rica em antioxidantes e com pouca quantidade de gorduras pode reduzir o risco de obesidade e resistência à insulina, investigou-se o efeito da casca de jabuticaba liofilizada sobre as concentrações plasmáticas de glicose, frações lipídicas, aspartato aminotransferase e alanina aminotrasferase em ratos Wistar machos adultos. Os animais foram distribuídos nos seguintes grupos: G0, o grupo controle e G1, G2 e G4, os grupos que receberam 1, 2 e 4%, respectivamente, do pó de casca de jabuticaba liofilizada adicionado à dieta AIN-93M. A suplementação reduziu as concentrações de glicose nos grupos G1 e G2, porém no grupo G3 esse efeito não foi encontrado. O colesterol total sofreu redução para os animais tratados com 1% de cascas de jabuticabas em relação ao grupo controle, mas os animais tratados com 2 e 4% de cascas de jabuticabas sofreram aumento no colesterol total e da fração LDL-colesterol, porém, o valor para colesterol total apresenta-se dentro da faixa normal para ratos Wistar. Os triacilgliceróis e a fração HDL-colesterol não sofreram alterações significativas. Os resultados indicam um possível benefício da suplementação da casca de jabuticaba na redução da glicemia plasmática, dos níveis de LDL e colesterol total e a possível existência de uma dose recomendada / Abstract: The objective of this study was to evaluate the antioxidant effects of anthocyanin and the antioxidant effects of peel jabuticaba powder in laboratory animals. Many tropical fruits are rich in anthocyanins, but there are few data available on the characterization and quantification of these anthocyanins. The identification and quantification of anthocyanins from bark jabuticaba was performed by HPLC-PDA and LC-ESI-MS/MS Q-TOF. The analysis revealed the presence of two compounds, delphinidin-3-glucoside and cyanidin-3-glucoside (635, 3 and 1964 mg/100 dry weight, respectively). ORAC, DPPH and ABTS methods were used for antioxidant analysis and the results were, 25514,24±3037,24 µMTEAC.g-1, 45.38 Yg.ml-1, 9457,74±54,29 µMTEAC.g-1, respectively. The total phenolics (Folin-Ciocalteau method) revealed that the jabuticaba powder contained 556,28±20,37 gGAEb.kg-1. In this study, freezedried peel jabuticaba showed great antioxidant proven by all methods antioxidants tested. The effects of the ingestion of jabuticaba peel in the antioxidant capacity of plasma of rats was investigated in two 'in vivo¿ experiments. In the first test, the absorption kinetics were evaluated. The male rats were divided into 5 groups received, by gavage, 7 mg anthocyanins / 100 g of body weight. Blood collection was performed at 0, 30, 60 and 120 minutes. The antioxidant potential was quantified in plasma by ORAC and TEAC. In this experiment there was no significant difference in plasma antioxidant potential when comparing the different times. In the second experiment, 40 rats were divided into 4 groups that consumed, respectively, 0, 1, 2 and 4% powdered peel jabuticaba lyophilized plus diet. We observed an increase in plasma antioxidant potential (1.7 times by the method of TEAC and ORAC by 1.3 4 times), but the concentration of 4% had no antioxidant effect. We investigated the effect of freeze-dried peel jabuticaba on plasma glucose, lipid fractions, aminotransferase and aspartate aminotransferase alanian in adult male Wistar rats. The animals assigned to groups G0, the control group, G1, G2 and G4 groups receiving 1, 2 and 4%, respectively, of freeze-dried peel jabuticaba added to the AIN-93M diet. Supplementation reduced the concentration of glucose in G1 and G2, but in G4 this effect was not found. Total cholesterol was reduced in animals treated with 1% bark jabuticabas in the control group, but animals treated with 2 and 4% experienced an increase in total cholesterol and LDL cholesterol, but the value for cholesterol total amount is within the normal range for rats. Triglycerides and HDL-cholesterol did not change significantly. The results indicate the possible benefit of supplementing with bark jabuticaba in reducing plasma glucose, LDL cholesterol and total cholesterol and the possible existence of a dose / Mestrado / Nutrição Experimental e Aplicada à Tecnologia de Alimentos / Mestre em Alimentos e Nutrição
22

Sistemas inteligentes e biodegradáveis = incorporação de indicadores de temperatura / Intelligent and biodegradable systems : temperature indicator

Maciel, Vínicius Borges Vieira, 1983- 04 August 2011 (has links)
Orientadores: Telma Teixeira Franco, Cristiana Maria Pedroso Yoshida / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-18T06:37:13Z (GMT). No. of bitstreams: 1 Maciel_ViniciusBorgesVieira_M.pdf: 5300890 bytes, checksum: ec3a873a5ab6ee31375cae1dd06832d3 (MD5) Previous issue date: 2011 / Resumo: Embalagem inteligente é uma tecnologia inovadora que permite a comunicação de informações relacionadas à qualidade e segurança do produto envolvendo a incorporação de sensores ou indicadores que produzem um sinal como resposta a qualquer alteração das condições iniciais. No setor de alimentos e fármacos, uma embalagem com barreiras efetivas a gases, umidade e luz não garante a total qualidade do produto, se as condições de temperatura durante o transporte e armazenamento não forem rigorosamente cumpridas. Desta forma, o monitoramento da temperatura, que apresenta efeito significativo nas reações de deterioração, é um fator importante para garantir qualidade e segurança do produto até o consumidor. O objetivo deste projeto foi o desenvolvimento de sistemas indicadores colorimétricos obtidos a partir de filmes de quitosana contendo pigmentos naturais termossensíveis, com potencial para aplicação como material para formação de embalagens inteligentes que comunicam a variação de temperatura. A quitosana é um polímero biodegradável, proveniente de fontes renováveis, capaz de formar filmes flexíveis e resistentes, com barreira efetiva ao oxigênio. Os pigmentos naturais estudados neste trabalho foram clorofila (CLO) e antocianina (ATH), escolhidos por serem de baixa toxidade, termossensíveis e apresentarem diferentes faixas de estabilidade de temperatura. Pigmento natural na concentração de 0,25% (m/m) foi incorporado à suspensão de quitosana (2,0%, m/m). Os efeitos da temperatura (10° a 50°C) e IL (0 a 1000 Lux) foram estudados utilizando um planejamento experimental de duas variáveis, avaliando os paramentos de cor L*, a* e b* e propriedades mecânicas dos filmes. As suspensões de quitosana contendo os pigmentos foram aplicadas como revestimento em superfície de papel cartão formando o sistema filme-papel cartão (FP). A alteração de cor para os filmes e sistema FP foi avaliada após exposição a diferentes temperaturas e IL. Os filmes caracterizaram-se pela homogeneidade, flexibilidade, transparência e fácil manuseabilidade. A variação de cor foi visualmente observada no sistema FP contendo CLO, mudando de verde para amarelo quando submetido a temperaturas acima de 50°C independente da IL e de roxo tendendo ao amarelo no sistema FP contendo ATH, para temperaturas acima de 40°C, sendo a alteração de cor intensificada na presença de IL / Abstract: Intelligent packaging is a technology that brings information related to the quality and safety of products. The system involves sensors or indicators incorporation that produce a signal as a response to any initial change conditions. In food and drug sectors, a packaging with effective barriers to gases, moisture and light no ensure the total product quality if the temperature conditions during transport and storage are not controlled. Temperature monitoring, that shows significant effect on deterioration reactions, is an important factor to guarantee the product integrity. The objective of this work was develop a colorimetric indicator system obtained from chitosan films containing thermal sensitive natural pigments. The potential application is as intelligent material packaging that communicates temperature changes. Chitosan is a biodegradable polymer, obtained from renewable source and has the ability to form flexible and resistant films with an efficient oxygen barrier. Natural pigments chlorophyll (CLO) and anthocyanin (ATH) were chosen due to their low toxicity, thermal sensitivity and stability in different range of temperatures. Pigment (0.25%, w/w) was incorporated to chitosan suspensions (2.0%, w/w). The temperature (10 to 50°C) and luminosity (0 to 1000 Lux) effects were studied using an experimental design with two variables, analyzing the colour parameters L*, a*, b* and mechanicals properties of chitosan films. The chitosan suspensions containing the pigments were applied as coating on card paper surface forming a card paper-film (FP) system. The colour changes of intelligent systems were evaluated after different temperature and luminosities exposition. The films were characterized by homogeneity, flexibility, transparency and handling. The colour change was irreversible and visually observed in the FP system containing CLO from green to yellow when submitted to temperature above 50°C despite the luminosity. For FP system containing ATH the colour change from purple to yellow for temperatures exposition above 40°C, where the colour change was intensified on luminosity presence / Mestrado / Processos em Tecnologia Química / Mestre em Engenharia Química
23

Extração, estabilidade e quantificação de antocianinas de frutas tipicas brasileiras para aplicação industrial como corantes / Extraction, stability and qualification of anthocyanins of Brazilian typical fruits for industrial application as colorants

Favaro, Martha Maria Andreotti, 1981- 28 January 2008 (has links)
Orientador: Adriana Vitorino Rossi / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-11T04:59:51Z (GMT). No. of bitstreams: 1 Favaro_MarthaMariaAndreotti_M.pdf: 1938335 bytes, checksum: 34f7f06916d0509676423ad381a2e27d (MD5) Previous issue date: 2007 / Resumo: Antocianinas (ACYS) são corantes encontrados em vegetais, responsáveis pela coloração de flores, frutas e folhas de azul a vermelho. A proposta de estudos analíticos envolvendo extração, estabilidade e quantificação de ACYS, visando a obtenção de extratos padronizados a partir de diferentes frutas, leva em consideração as novas perspectivas do uso desses pigmentos como corantes em diversos segmentos da indústria, tais como, farmacêutico, cosmético e alimentício. Neste trabalho, foram estudadas 3 frutas típicas brasileiras congeladas: jabuticaba (Myrciaria cauliflora), amora (Morus nigra) e amora preta (Rubus sp), visando maximizar a quantidade de ACYS extraídas e obter extratos com maior durabilidade. As condições estudadas foram: tipo de solvente, adição de conservantes em solvente aquoso, temperaturas de extração e armazenamento, tempo de armazenamento e, para a jabuticaba, foi estudada a influência do uso da fruta inteira na extração e estabilidade dos extratos. O solvente extrator que apresentou maior capacidade extratora além de oferecer maior estabilidade aos extratos foi etanol 94% v/v. O conjunto de conservantes Nipagin 0,01 % m/v +Nipazol 0,05 % m/v forneceu os melhores resultados, reduzindo a degradação das ACYS e impedindo o aparecimento de fungos. Em condição otimizada, foram encontrados os seguintes teores de ACYS nas frutas, expressos em mg ACYS / 100 g: 40,0±0,2 em casca de jabuticaba, 153±3 em amora e 83±2 em amora preta. Estudos comparativos de diversos procedimentos de quantificação de ACYS, incluindo o método oficial e padrões de ACYS, foram realizados, incluindo-se simplificações, visando aplicação de rotina industrial. Medidas de absorbância dos extratos em pH 1,0 no comprimento de onda de absorção máxima das ACYS mostraram ser adequadas para quantificar ACYS totais sem a necessidade do uso de padrões comerciais / Abstract: Anthocyanins (ACYS) are pigments found in plants that give colors from red to blue to flowers, fruits and leaves. The proposal of analytical studies involving extraction, stability and quantification of ACYS from different fruits takes into account the new perspectives of using these pigments in several segments of the industry, such as, pharmaceutical, cosmetic and food. In this work, extracts of 3 Brazilian typical frozen fruits: jaboticaba (Myrciaria culiflora), mulberry (Morus nigra) and blackberry (Rubus sp), were studied aiming to maximize the amount of extracted ACYS and to obtain extracts with longer durability. The studied conditions were: type of solvent, addition of preservatives in aqueous solvent, temperature of extraction and storage and storage time. The influence in extraction and stability of the extracts using the whole fruit was studied for jaboticaba. Ethanol 94% v/v was the extractor solvent which resulted in greater capacity of extraction and affered the most stable extracts. The mixture of Nipagin 0,01 % w/v + Nipazol 0,05 % w/v preservatives provided the best results, reducing the degradation of ACYS and preventing the fungi emergence. At optimized conditions, the levels of ACYS in the fruits, expressed in mg ACYS / 100 g were: 40,0±0,2 in jabuticaba, 153±3 in mulberry and 83±2 in blackberry. Comparative studies of different procedures for quantification of ACYS, including the official method and the use the ACYS commercial standards were done, including simplifications to be used in industrial routine. The results showed that the method which uses measurements of absorbance of extracts at pH 1,0 and at the wavelength of maximum absorption of ACYS allows easily quantify total ACYS without necessity of using commercial standard / Mestrado / Quimica Analitica / Mestre em Química
24

Compostos bioativos em amora-preta e encapsulação do seu extrato antocianico por gelificação termica com curdlana / Bioactive compounds in blackberry (Rubus spp.) and encapsulation of blackberry anthocyanins using gelification of curdlan

Ferreira, Daniela Souza, 1978- 15 July 2008 (has links)
Orientador: Adriana Zerlotti Mercadante / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-11T06:49:41Z (GMT). No. of bitstreams: 1 Ferreira_DanielaSouza_M.pdf: 861449 bytes, checksum: 0972445ef423fb371289eeef23009060 (MD5) Previous issue date: 2008 / Resumo: Dentre as várias opções de espécies frutíferas com boas perspectivas de comercialização, surge a amora-preta (Rubus spp.) como umas das mais promissoras. A amora-preta é uma pequena fruta que tem apresentado sensível crescimento nos últimos anos no Rio Grande do Sul, Sul de Minas Gerais e tem elevado potencial para ser cultivada no estado de São Paulo. No Rio Grande do Sul, a amora-preta tem tido grande aceitação pelos produtores, devido ao seu baixo custo de produção, facilidade de manejo, rusticidade e pouca utilização de defensivos agrícolas. Muitos fitoquímicos presentes em amora-preta exibem propriedades benéficas à saúde, como compostos fenólicos, com destaque para os pigmentos antociânicos. Estes pigmentos, que conferem a coloração atraente à fruta, possuem baixa estabilidade frente a algumas condições do meio como pH neutro e alcalino, alta temperatura e presença de luz. Assim, através deste estudo foram determinados espectrofotometricamente o teor de alguns compostos bioativos presentes em amora-preta cultivar Tupy, como antocianinas totais, monoméricas, poliméricas e copigmentadas, além de compostos fenólicos totais, flavonóides totais e carotenóides. A atividade antioxidante foi avaliada frente aos radicais ABTS e DPPH. Por cromatografia líquida de alta eficiência (HPLC), acoplada em série a detectores de arranjo de diodos (PDA) e de espectrômetro de massas (MS) foram identificadas as antocianinas e os carotenóides presentes no extrato de amora. Com o intuito de aumentar a estabilidade das antocianinas, o extrato antociânico da amora-preta foi encapsulado utilizando a técnica de gelificação térmica. O material de parede selecionado foi a curdlana por não perder a capacidade gelificante em pH abaixo de 2. Após o processo de encapsulação foram avaliadas algumas características das partículas como o tamanho médio, a eficiência de encapsulação e o perfil de liberação do recheio. As antocianinas identificadas em amora-preta foram cianidina 3-glucosídeo, cianidina 3-dioxalil-glucosídeo, cianidina 3-malonil-glucosídeo e cianidina 3- rutinosídeo. A antocianina majoritária foi a cianidina 3-glucosídeo perfazendo 92,9 % da área total. O teor de antocianinas totais foi de 90,5 ± 0,1 mg/100 g, sendo composto por 76,2 ± 0,3 % de monoméricas, 22,8 ± 0,4 % de poliméricas e 1,6 ± 0,1 % de copigmentadas. As antocianinas monoméricas foram encontradas como 104,1 ± 1,7 mg em cianidina 3-glucosídeo/100 g de fruta. Foi observado que a amora-preta possui baixo teor de carotenóides (86,5 ± 0,1 mg/100 g) e os carotenóides encontrados foram: all-trans-b-caroteno (39,6 %), all-trans-luteína (28,2 %), all-trans-b-criptoxantina (13,9 %), 9-cis-b-caroteno (3,8%), all-trans-a-caroteno (3,3 %), 13-cis-b-criptoxantina (3,1 %), all-transzeaxantina (2,7 %), 13-cis-b-caroteno (1,7 %), 5,6-epóxi-b-criptoxantina + fitoeno (0,8%), além de um carotenóide não identificado representando 2,9 %. Com a presença de elevados teores de compostos fenólicos totais (241,7 ± 0,8 mg/100 g) e de flavonóides totais (173,7 ± 0,7 mg/100 g), pode-se concluir que estes compostos presentes na amora-preta foram os principais responsáveis pela elevada capacidade antioxidante avaliada pela habilidade de capturar radicais livres ABTS (TEAC 2209,7 ± 68,4 mM/ g) e DPPH (EC50 33,8 ± 1,8 g amostra/g DPPH). As partículas formadas por gelificação térmica com 4,3, 5,1 e 5,6 % de curdlana apresentaram forma esférica e multinucleada. A distribuição de tamanho apresentou perfil semelhante para as diferentes concentrações de curdlana, embora as partículas obtidas com maior concentração de curdlana (5.6 %) apresentaram maior uniformidade no tamanho, maior umidade e maior eficiência de encapsulação. O perfil de liberação de todas as partículas contendo antocianinas apresentou cinética exponencial de primeira ordem, com total liberação nos primeiros 20 minutos em tampão pH 1,0 / Abstract: Among the fruit species with good perspectives for commercialization, blackberry fruit (Rubus spp.) is one of the best options. Blackberry is a small fruit, which has been increasingly cultivated in Rio Grande do Sul State, South of Minas Gerais State, also presenting high potential for cultivation in São Paulo State. In Rio Grande do Sul, blackberry has been widely accepted by the farmers, due to its low production cost, easy handling, rusticity and use of low amounts of agricultural defensives. Several phytochemicals found in blackberry, such as phenolic compounds and anthocyanins, show beneficial health properties to humans. The anthocyanins, responsible for the attractive color of blackberries, possess low stability in some medium conditions, such as neutral and alkaline pH, high temperature and presence of light. Thus, using spectrophotometric methods, the levels of some bioactive compounds were determined in blackberries cv. Tupy, such as total anthocyanins, monomeric, polymeric and copigmented anthocyanins, as well as phenolic compounds, total flavonoids and total carotenoids. The antioxidant activity was determined using the free radicals ABTS and DPPH. Both anthocyanins and carotenoids from blackberry extracts were separated and identified by high performance liquid chromatography (HPLC) connected in series to diode array (PDA) and mass spectrometer (MS) detectors In order to increase the anthocyanin stability, the anthocyanic blackberry extract was encapsulated by thermal gelification. Curdlan was the wall material selected, since the gel formed was stable in pH values lower than 2. After the encapsulation process, some particle characteristics, such as medium size, encapsulation efficiency and release profile, were evaluated. The anthocyanins identified in blackberry were cyanidin 3-glucoside, cyanidin 3-dioxalyl-glucoside, cyanidin 3-malonil-glucoside and cyanidin 3-rutinoside. The major anthocyanin was cyanidin 3-glucoside, representing 92.9 % of the total area. The levels of total anthocyanins were 90.5 ± 0.1 mg/100 g, composed by 76.2 ± 0.3 % of monomeric, 22.8 ± 0.4 % of polymeric and 1.6 ± 0.1 % of copigmented ones. The monomeric anthocyanins were quantified as 104.1 ± 1.7 mg of cyanidin 3-glucoside/100 g of fruit. The levels of carotenoids found in blackberry were low (86.5 ± 0.1 mg/100 g), represented by all-trans-b-carotene (39.6 %), all-trans-lutein (28.2 %), all-trans-b-cryptoxanthin (13.9 %), 9-cis-b-carotene (3.8%), all-trans-a-carotene (3.3 %), 13-cis-b-cryptoxanthin (3.1 %), all-trans-zeaxanthin (2.7 %), 13-cis-b-carotene (1.7 %), 5,6-epoxy-b-cryptoxanthin + phytoene (0.8%), and a not identified carotenoid representing 2.9 %. The elevated levels of phenolic compounds (241.7 ± 0.8 mg/100 g) and flavonoids (173.7 ± 0.7 mg/100 g) are most probably responsible for the high antioxidant activity against the free radicals ABTS (TEAC 2209.7 ± 68.4 mM/100g) and DPPH (EC50 33.8 ± 1.8 g sample/g DPPH). The particles formed by thermal gelification with 4.3, 5.1 and 5.6 % of curdlan presented spherical and multinucleated forms. The profiles of the size distribution were similar for all curdlan concentrations; although the particles with the highest curdlan concentration (5.6 %) showed highest size distribution uniformity, highest moisture and highest encapsulation efficiency. The release profile of anthocyanins from all particles followed first-order kinetics, with total release in 20 minutes in buffer pH 1.0 under agitation at room temperature / Mestrado / Mestre em Ciência de Alimentos
25

Complexos dos polieletrólitos quitosana e pectina para obtenção de sistemas carreadores de compostos bioativos / Polyelectrolyte complex chitosan and pectin for obtaining carriers systems of bioactive compounds

Maciel, Vínicius Borges Vieira, 1983- 27 August 2018 (has links)
Orientadores: Telma Teixeira Franco, Cristiana Maria Pedroso Yoshida / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-27T09:35:25Z (GMT). No. of bitstreams: 1 Maciel_ViniciusBorgesVieira_D.pdf: 3450420 bytes, checksum: 93b85fa848aed2fac2f71661da3c2d09 (MD5) Previous issue date: 2015 / Resumo: Complexos de polieletrólitos (PEC) podem ser obtidos a partir de polímeros que apresentam cargas opostas, como quitosana e pectina. A inovação deste trabalho foi desenvolver sistemas carreadores de compostos bioativos (antocianina (ATH) e insulina), na forma de membranas e nanocomplexos (NCXs) obtidos a partir da interação eletrostática existente entre os polímeros naturais quitosana e pectina. Quitosana é um polímero linear catiônico composto por N-glucosamina e N-acetilglucosamina, e apresenta diferentes graus de acetilação (GA). Pectina é um polímero linear aniônico composto principalmente por ácido D-galacturônico com uma fração dos grupos carboxilas sendo metoxilados. Membranas PEC foram desenvolvidas para incorporar a ATH formando um dispositivo inteligente indicador de pH, com alteração visual e reversível da cor. NCXs foram elaborados na forma de micro/nanopartículas carregadas de insulina (pI = 5,3) para avaliar a liberação controlada do fármaco, via oral, em sistemas in vitro. Membranas PEC foram estudadas usando quitosana e pectina em diferentes pH (3,0, 4,0, 5,0 e 5,5) e relações molares pectina:quitosana. Soluções de pectina e quitosana, ambas de 0,50 g/100 g de solução e mesma força iônica foram misturadas e homogeneizadas. As membranas PEC apresentaram superfície rugosa e parcialmente homogênea. A máxima formação do PEC foi em pH 5,5, com aproximadamente 60,0 % de rendimento. O processo de difusão do bioativo ATH a partir das membranas PEC indicou que o composto foi incorporado na matriz, onde menos de 2,0 % (em massa) do bioativo migrou para a solução tampão em que estavam imersos (pH 4,0, 5,5 e 7,0). A compatibilidade entre os polímeros e ATH foi verificada pelas análises termogravimétricas, microscopia eletrônica de varredura, espectroscopia de infravermelho com transformada de Fourier e difração de raios X. Os NCXs foram obtidos a partir da homogeneização das soluções de quitosana (5,0 mg/mL) e pectina (5,0 mg/mL) em diferentes pH (2,70, 4,0, 5,0 e 5,5), relações de carga, carga total e molaridade das soluções de NaCl. A melhor condição para obtenção das micro/nanopartículas foi em pH < 4,0, havendo formação de partículas entre 250-2500 nm e rendimento de formação entre 18-33 % (em massa). O GA da quitosana influenciou na citotoxicidade das células Caco-2. A relação de carga promoveu efeito significativo na associação da insulina às partículas, na ordem de 34,0-62,0 %. As micrografias indicaram a formação de partículas esféricas, compactas e distribuídas homogeneamente. A liberação de insulina ocorreu de forma lenta e gradativa em fluido intestinal simulado (SIF) / Abstract: Polyelectrolyte complex (PEC) with very strong intermolecular interaction can be obtained from polysaccharides that present opposite charges such as chitosan and pectin. The innovation of this work was developing carrier systems of bioactive compounds (anthocyanin (ATH) and insulin) using membranes and nanocomplexes (NCXs) obtained from electrostatic interaction that exists between the polymers chitosan and pectin. Chitosan is a linear cationic polysaccharide composed by N-glucosamine and N-acetil glucosamine and presents different degree of acetylation (DA). Pectin is a linear anionic polysaccharide composed mainly by D-galacturonic acid with one part of carboxyl group methoxylated. PEC membranes were developed to entrap ATH forming an intelligent pH indicator device, with visual and reversible colour change. NCXs were elaborated such as micro and nanoparticles loading insulin (pI = 5.3) to evaluate drug controlled delivery, oral pathway, in systems in vitro. PEC membranes were studied using chitosan and pectin in different pH (3.0, 4.0, 5.0, and 5.5) and molar ratios pectin:chitosan. Pectin and chitosan solutions, both at 0.50 g/100 g of solution and the same ionic force were mixed and homogenized. PEC membranes were characterized by rough and partially homogeneous surface. The maximum PEC formation was at pH 5.5, with approximately 60.0 % of yield. The diffusion process of bioactive ATH from PEC membranes indicated great entrapment of compound on matrix, where less than 2.0 % (mass) of pigment migrated to the aqueous buffer solution (pH 4.0, 5.5 and 7.0). The compatibility between the polymers and ATH was verified by thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The NCXs were obtained from homogenization of chitosan (5.0 mg/mL) and pectin (5.0 mg/mL) solutions at different pH (2.7, 4.0, 5.0 and 5.5), charge ratios, total charge and molarity of NaCl solutions. The best condition to obtain micro/nanoparticles was in pH < 4.0, with size particles formation between 250-2500 nm and yield of NCXs formation between 18-33 % (mass). The DA of chitosan influenced on cytotoxicity of Caco-2 cells. The charge ratio promoted significant effect on drug efficient association to the particles, around 34.0-62.0 %. The micrograpH indicated the formation of shape and compact particles distributed homogeneity. The insulin delivery occurred slowly and gradually on simulated intestinal fluid (SIF) / Doutorado / Engenharia de Processos / Doutor em Engenharia Química
26

Strategies for Increasing the Release of Pigments in Red Wine

Heywood, Briana 01 August 2017 (has links)
The perception of wine’s quality is directly influenced by its color. Anthocyanin molecules are responsible for imparting color to red wines. They are extracted from grape skins during alcoholic fermentation. This work compares the effects of three parameters: berry integrity, enzyme addition, and fermentation temperature, on phenolic compound extraction (total phenol, tannin and anthocyanin) during the production of Paso Robles’ Cabernet Sauvignon wine. Analyses on phenolic compounds were completed during alcoholic fermentation and barrel aging over the course of eighteen months. Berry integrity compared the degree of berry crushing (whole destemmed berries versus fully crushed berries). Results showed that phenolic compound content after alcoholic fermentation seem to be unaffected by this parameter, while minor increases in total phenol concentration (3%) and tannin concentration (3%) during barrel aging were observed. Adding pectinase-rich macerating enzymes increased the total phenols by 8.7 and 21.0% to the 2010 and 2011 vintage, respectively, and tannin concentrations by 20.8 and 48.8%, respectively, during barrel aging. Alcoholic fermentation temperature of 25.0°C was compared to a fermentation temperature of 32.2°C in the 2011 vintage. When fermented at 32.2°C, concentrations of total phenol and tannin were significantly increased (20.6% and 28.9%, for the 2010 and 2011 vintages, respectively) when compared to 25.0°C. A cooler fermentation temperature led to 57.5% greater anthocyanin concentration throughout barrel aging. The results suggested that fermenting berries at a cooler temperature (25.0°C) increased anthocyanin levels and decreased total phenol and tannin concentration, which are desired outcomes for Paso Robles’ Cabernet Sauvignon wine quality.
27

Evaluation of Pigments from a Purple Variety of Atriplex hortensis L. for Use in Food Applications

Vila Roa, Eva Graciela 01 June 2018 (has links)
Atriplex hortensis L., also known as orach, is a leafy vegetable from the Amaranthaceae family, which has historically been consumed as a potherb, like spinach. The brightly colored leaves are a source of high quality protein, but may also be of interest as a potential source of natural food pigments. An aqueous extraction was obtained from the freshly harvested leaves of the'Triple Purple' variety of A. hortensis. The extract was spray-dried into a powder, and individual pigments were analyzed using HPLC and LC-MS. The powder was also included as a color additive in a typical stabilizer/sweetener preparation and mixed into plain yogurt. Two batches of colored yogurt were held under light and dark conditions and tested for pH and color (L*a*b*) every 15 days. A visual sensory panel was performed on days 0, 45, and 90 to evaluate the color acceptance.A total of three types of betacyanins and six types of anthocyanins were tentatively identified by HPLC and/or LC-MS. Orach pigments in yogurt were not stable under full light exposure. The color of samples exposed to light degraded within days. There were statistically significant differences found in L*a*b* scores in the dark treatment, beyond 30 days; but these modest changes in dark-stored samples were not found to be statistically significant in the consumer sensory panel. The tentative identification of both anthocyanins and betacyanins in orach is a novel finding in botanical research, as the literature indicates that these two pigment classes are mutually exclusive. The application of heat during pigment extraction, spray drying, and yogurt color additive preparation, did not appear to appreciably affect stability of orach pigments, indicating that orach extract could be used as a color in different process applications, if protected from light.
28

Evaluation of Antioxidant Properties of Native Utah Berries and Their Potential for Use in Meats

Wang, Xiaoxi 01 December 2018 (has links)
In industry, antioxidants are added to prevent changes that affect quality due to oxidation, such as the development of off flavors, unacceptable odors and discoloration. New resources that are familiar to consumers and may work as antioxidants should be studied. The changes in antioxidant activity were determined for four freeze-dried native wild berry powder species in Utah, including skunkbush (Rhus trilobata), chokecherry (Prunus virginiana), river hawthorn (Crataegus douglasii) and silver buffaloberry (Shepherdia argentea), during cold storage (-20 °C) for 6 months. The total antioxidant activity was stable in most of the berry powders during the six months of frozen storage. Overall the river hawthorn and buffaloberry contained the highest antioxidant activity values, which indicated that they would be more efficient for use as food antioxidants. The effectiveness of two different levels of native Utah river hawthorn and buffaloberry freeze-dried powders in maintaining the quality of ground poultry and ground beef was studied. Meat patties mixed with berry powders were held at 4 °C and analyzed every three days for two weeks. The river hawthorn berry and silver buffaloberry delayed the undesirable changes in flavor or color caused by the oxygen present in the air in both chicken and beef ground patties. However, the plant pigments in the silver buffaloberry increased the redness of chicken patties. Neither berry significantly changed the color of ground beef patties or changed the microbial growth in ground meats. Overall, both river hawthorn and buffaloberry are suitable for using in ground beef product as antioxidants. Milk mineral and sodium tripolyphosphate are antioxidants that could bind free metal ions into insoluble or inactive forms. They can delay the changes of the meat pigment and maintain color in meat products. The purpose of the third study was to examine the effect antioxidants on meat pigment.pH describes the amounts of acid in food. Slowed color changes in the poultry meat pigment with antioxidants was seen both at the pH of living poultry muscle (7.2) and the pH of raw poultry meat (pH 6.0). This suggested that addition of metal-binding antioxidants like milk mineral or sodium tripolyphosphate could help preserve poultry meat pigment and maintain the color of poultry products.
29

Amalysis of Procyanidins and Anthocyanins in Food Products using Chromatographic and Spectroscopic Techniques

Wallace, Taylor C. 20 August 2010 (has links)
No description available.
30

Genetic Study of Compositional and Physical Kernel Quality Traits in Diverse Maize (<i>Zea mays</i> L.) Germplasm

Ryu, Si Hwan January 2010 (has links)
No description available.

Page generated in 0.1344 seconds