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Biofilmes a base de amido, gelatina e extrato de Tetradenia riparia na conservação de morango / Biofilms based on starch, gelatine and Tetradenia riparia extract on strawberry conservationFriedrich, Jussara Carla Conti 02 March 2017 (has links)
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Previous issue date: 2017-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Strawberry is a non-climacteric pseudofruit and has a short shelf life after harvest. Among the factors responsible for the loss of quality of strawberries are high metabolic activity and high susceptibility to microbial attack. Therefore, studies with edible coverings or coverings are being one of the most appropriate alternatives to assist in the post harvest conservation of fruits, especially non-climacteric ones such as strawberry. These coatings have excellent barrier properties, mainly to the transport of gases and water vapor, among other factors that contribute to the maintenance of fruit quality. Therefore, the objective of this work was to evaluate the effect of edible films produced from gelatine, native starch, sorbitol and Tetradenia riparia extract (antimicrobial agent) in the post harvest harvesting of strawberries (Fragaria ananassa). The films were analyzed for thickness, solubility, opacity, colorimetry, TVA (water vapor transmission) and mechanical analysis. The films that received the addition of Tetradenia riparia extract became thicker with lower solubility and opacity, and greater luminosity. These data corroborated the mechanical analysis, in which the films with extract were more elastic, in addition, it was necessary to apply a greater force to break, that is, more resistant. Regarding the fruits, the analyzes were performed on alternate days, during 10 days of storage, under temperature and humidity of refrigerator with temperature of 8ºC at 10ºC and relative humidity of approximately 75%, being evaluated the loss of mass, microbiological analysis, analysis Antioxidant, calorimetry, vitamin C contents, total soluble solids (TSS), titratable total acidity (TTA) and the relationship between both SST / ATT. The loss of mass increased with the prolongation of the storage, that is to say, when adding the extract of Tetradenia riparia both in medium and in high inhibition the losses of mass of the fruits were superior to 10% in the 4th day of storage, for the two treatments mentioned above. As for the contents of total soluble solids and titratable total acidity the contents increased with the increase of the storage period, this fact may be related to the respiratory process and consumption of organic acids. Regarding the vitamin C content, only the treatments that did not receive the addition of extract continued to increase the contents at the end of the experiment. This proves the importance of using biofilm as a protective agent, it is also observed that these fruits that the coloration decreases, leaving the less looking less shiny. Microbiological analysis showed that the most effective treatment was the high inhibition of starch film (FAAI), that is, 500 μg / ml of Tetradenia riparia extract was enough to decrease the number of colony forming units at the end of experiment. For the antioxidant activity it was observed that the most efficient treatments were those with the addition of T. riparia extract to the films that is, when adding 500μg / ml or 1000μg / ml, they presented a decrease of the antioxidant activity, indicating that the Extract may reduce metabolic activity and delay fruit senescence. / O morango é um pseudofruto não climatérico e que tem uma curta vida útil após a colheita. Entre os fatores responsáveis pela perda de qualidade dos morangos estão alta atividade metabólica e alta susceptibilidade ao ataque microbiano. Diante disso, estudos com revestimentos ou coberturas comestíveis estão sendo uma das alternativas mais apropriada para auxiliar na conservação pós colheita de frutas principalmente as não climatéricas como é o caso do morango. Estes recobrimentos podem possuir excelentes propriedades de barreira, principalmente ao transporte de gases e vapor de água, entre outros fatores que contribuem para manutenção da qualidade do fruto. Desta forma, o objetivo deste trabalho foi avaliar o efeito de filmes comestíveis produzidos a partir de gelatina, amido nativo, sorbitol e extrato de Tetradenia riparia (agente antimicrobiano) na conservação de morangos em pós- colheita. Os filmes foram analisados em relação à espessura, solubilidade, opacidadade, colorimetria, TVA (transmissao de vapor de agua) e análise mecânica. Em relação aos frutos, as análises foram realizadas em dias alternados, durante 10 dias de armazenamento, sob refrigeracão com temperatura de 8ºC á 10ºC e umidade relativa de aproximadamente 75%, sendo avaliados a perda de massa, análise microbiológica, análise antioxidante, calorimetria, vitamina C, sólidos solúveis totais (SST), acidez total titulável (ATT) SST/ATT. Os filmes que receberam a adição do extrato de Tetradenia riparia tornaram-se mais espessos com menor solubilidade e opacidade, e maior luminosidade. Estes dados corroboraram a análise mecânica, em que, os filmes com extrato mostraram-se mais elásticos, além disso, foi necessário aplicar uma força maior para que se rompesse, ou seja, mais resistentes. A perda de massa aumentou com o prolongamento do armazenamento, ou seja, ao adicionar o extrato de T. riparia tanto em média quanto em alta concentracao as perdas de massa dos frutos foram superiores a 10% no 4º dia de armazenamento, para os dois tratamentos citados acima. Quanto aos teores de sólidos solúveis totais e acidez total titulável os teores aumentaram com o aumento do período de armazenamento. Em relação ao teor de vitamina C, apenas os tratamentos que não receberam a adição de extrato continuaram a aumentar os teores ao final do experimento. Isto comprova a importância da utilização de biofilme como agente de proteção, também observa-se que estes frutos que a coloração diminui, deixando os menos com aspecto menos brilhante. A análise microbiologica mostrou que o tratamento mais eficaz, foi o filme de amido com alta concentracao de extrato (FAAI), ou seja, 500µg/ml de extrato de T. riparia foi o suficiente para diminuir o número de unidades formadoras de colônias ao final do experimento. Para a atividade antioxidante observou-se que os tratamentos mais eficientes foram aqueles com a adição de extrato de T. riparia aos filmes, ou seja ao adicionar 500µg/ml ou 1000µg/ml, os mesmos apresentaram uma diminuição da atividade antioxidante, indicando que o extrato pode reduzir a atividade metabólica e retardar a senescência dos frutos.
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Využití kapilární elektroforézy pro stanovení vybrané skupiny flavonoidů / Use of capillary electrophoresis to determine a selected group of flavonoidsTran Xuan, Tiep January 2021 (has links)
In recent years, the use of natural medicinal properties of plants has again come to the forefront of interest of the public. Because of their therapeutic properties, these plants are commonly used in alternative treatments for minor ailments. This thesis deals with the determination of polyphenolic acids in extracts from aronia, echinacea, tetradenia and centella. One of the aims of the thesis was to compare the amount of polyphenolic acids in individual plants with their antioxidant properties. The theoretical part includes a general introduction to flavonoids, introduction to polyphenolic acids, introduction to the principles of capillary zone electrophoresis and a summary of selected foreign studies for the determination of flavonoids. An important chapter of the theoretical part is a description of individual plants with an explanation of their possible therapeutic use. The experimental part is devoted to the process of optimization of electrophoretic determination of selected polyphenolic acids and evaluation of their content. It was found that in the extracts six representatives of polyphenolic acids occur in minimal amounts, often below the limit of quantification or detection of the method.
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Stanovení antimikrobiální a antioxidační aktivity vybraných bylinných extraktů / Determination of antimicrobial and antioxidant activity of selected herbal extractsČaková, Adriana January 2021 (has links)
Tetradenia spp. is herb naturally growing in Africa and is part of family called Lamiaceae. The herb is used in traditional medicine to cure malaria, angina or as treatment for tropical skin diseases. Maceration was chosen from number of extraction methods, to obtain bioactive compounds from this plant. Optimization was performed with aim to retrieve as much of bioactive compounds as possible. Optimal conditions chosen were: temperature 60 °C, extraction time 40 minutes, solvent 40% ethanol and solid-solvent ratio 1:5. In total 63 aromatic active compounds were found in optimal extract. Terpenes were the most abundant (88,60 %), from them oxygenated monoterpenes (55,65 %) and monoterpenes (29,52 %). Compounds with highest percentage quantity were camphor (51,76 %), cis--ocimene (8,17 %), 3-octyl acetate (7,71 %), trans--ocimene (6,76 %), -terpinene (4,93 %), o-cymene (3,81 %), terpinolene (1,33 %), limonene (1,33 %), camphene (1,19 %) and borneol (1,20 %). Further, total phenolic content was 0,31 ± 0,02 mgGAEml-1, which equals 1,52 ± 0,11 mgGAEg-1 of plant. Antioxidant activity was 417,56 ± 32,84 gTEACml-1 and percentage of radical scavenging activity ABTS•+ was 88,99 ± 7,00 %. Finally antimicrobial activity was determined against bacteria Bacillus cereus, Escherichia coli and yeast Candida glabrata. Against E. coli and C. glabrata there was no inhibition exhibited. Against B. cereus there was seen mild inhibition activity. The results confirm that Tetradenia spp. contain a number of interesting aroma active compounds, which shows antioxidant and antimicrobial activity. The herb has a good potential as natural source of nutritious and sensory active compounds to be used into various foods.
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