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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Matriz de AnÃlise Politica Aplicada a Cadeia Produtiva da Manga no MunicÃpio de Petrolina, Pernambuco / Matriz de AnÃlise Politica Aplicada a Cadeia Produtiva da Manga no MunicÃpio de Petrolina, Pernambuco

William Bruno Cerqueira AraÃjo 22 June 2015 (has links)
CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / Objetiva analisar o comportamento da cadeia produtiva da manga exportada para os Estados Unidos, por meio da utilizaÃÃo de indicadores privados e sociais, sob a perspectiva da Matriz de AnÃlise PolÃtica (MAP), no corredor Petrolina-PE ao porto de Salvador; assim como a atuaÃÃo de polÃticas pÃblicas sobre a cadeia estudada. Dessa forma, mostra-se um arcabouÃo da Matriz de AnÃlise PolÃtica com o intuito de oferecer suporte teÃrico e prÃtico à pesquisa. A busca exploratÃria foi o guia condutor deste estudo, aplicada por meio de abordagem qualitativa e quantitativa e desenvolvida com base em dados primÃrios e secundÃrios associados ao estudo de caso que foram estruturados por meio de matrizes contÃbeis organizadas em planilhas eletrÃnicas, desenvolvidas no software Excel - Microsoft 2010. Esses dados foram fornecidos por uma cooperativa e pelos cooperados produtores de manga, transportadoras, despachantes aduaneiros e instituiÃÃes de pesquisa, e coletados no MunicÃpio de Petrolina-PE. A lucratividade relacionada aos custos privados e sociais e polÃticas governamentais ofereceu os conceitos que fundamentaram as anÃlises realizadas neste estudo. Os produtores estudados no caso foram divididos, por estratos de Ãrea, em trÃs grupos. Foram calculadas seis matrizes contÃbeis, utilizando dados dos trÃs grupos, considerando e desconsiderando os gastos com as barreiras nÃo tarifÃrias relacionados Ãs exportaÃÃes da fruta ao mercado dos EUA. Desta forma, a anÃlise dos resultados obtidos permite concluir que, no conjunto dos elos da cadeia, a lucratividade privada e social e a eficiÃncia econÃmica do sistema sÃo positivas para todos os grupos, considerando ou nÃo os gastos com as barreiras nÃo tarifÃrias, mesmo ocorrendo transferÃncia de renda do produtor para a sociedade e taxaÃÃo na cadeia. Sendo assim, os trÃs grupos analisados denotam vantagens competitivas e comparativas, mesmo com a atuaÃÃo de efeitos negativos de polÃticas pÃblicas e de barreiras nÃo tarifÃrias impostas pelo Governo americano para a importaÃÃo da manga brasileira. A competitividade poderia ser maior caso nÃo houvesse as exigÃncias de importaÃÃo dos Estados Unidos. Consequentemente, a cadeia produtiva da manga voltada para a exportaÃÃo exprime perspectivas favorÃveis e tendÃncia de expansÃo, apesar dos "desincentivos". / The present study aimed to analyze the behavior of the production chain of mango exported to the United States, through the use of private and social indicators, from the perspective of Policy Analysis Matrix (PAM), in Petrolina-PE corridor to the port of Salvador; as well as the role of public policy on the studied chain. Thus, it presents a framework of Policy Analysis Matrix in order to provide theoretical and practical support to the research. Exploratory research was the guide to this study, applied by means of qualitative and quantitative approach and developed based on primary and secondary data associated with the case study that were structured through accounting matrices organized in spreadsheets developed using Excel - Microsoft 2010. These data were by cooperative mango producing companies, carriers, customs brokers and research institutions, and collected in the city of Petrolina-PE. The profitability related to the private and social costs and government policies, offered the concepts that underlie the analyzes performed in this study. The producers that have been studied in the case were divided in three groups. Six accounting matrices were calculated using data from three groups considering and excluding expenses on non-tariff barriers related to the fruit exportation to the US market. Thus, the analysis of the results shows that, in all the links of the chain, the private and social profitability and economic efficiency of the system are positive for all groups considering whether or not spending on non-tariff barriers, even occurring producer income transfer to society and taxation in the chain. Thereby, the three groups analyzed have competitive and comparative advantages, even with the performance of negative effects of public policies and non-tariff barriers imposed by the US government for the import of Brazilian mango. The presented competitiveness could be higher if there were the US import requirements. Consequently, the productive chain of mango aimed at exports has favorable prospects and expansion trend, despite the "discouragement".
82

Cascas liofilizadas de manga Tommy Atkins: teor de fitoquímicos bioativos e potencial antioxidante

ARAÚJO, Cristiane Rodrigues de 31 July 2012 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-07-26T12:47:23Z No. of bitstreams: 1 Cristiane Rodrigues de Araujo.pdf: 1357200 bytes, checksum: e679be2445ef965c1948578b245819fa (MD5) / Made available in DSpace on 2016-07-26T12:47:23Z (GMT). No. of bitstreams: 1 Cristiane Rodrigues de Araujo.pdf: 1357200 bytes, checksum: e679be2445ef965c1948578b245819fa (MD5) Previous issue date: 2012-07-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work had as objective to characterize of freeze-dried bark of mango Tommy Atkins, come from organic farming, and defining the conditions of the polyphenols extraction process. The peels were crushed and the flour was submitted to the determination of proximate composition, minerals and bioactive phytochemicals and antioxidant potential employing techniques titrimetric, spectrophotometric and chromatographic. To define the optimal conditions of the process was applied the of factorial design 2² as independent variables: temperature 25-50° C and time stirring 30 to 90 min), and as response the total phenolics concentration in the extract. This experimental design was applied in the following process types: a) Extraction sequentially- hydroacetonic solution (80%), followed by hydromethanolic solution (80%); b) Extraction sequentially- hydromethanolic solution (80%), followed by hydroacetonic solution (80% ); c) Extraction non-sequential-hydroacetonic solution (80%) and d) extraction non-sequential- hydromethanolic solution (80%). The extracts were submitted to antioxidant assays, capture radicals in model system (DPPH, ABTS, ORAC) and antioxidant assays in lipid systems (coupled oxidation of β -carotene-linoleic acid, peroxidation of linoleic acid - ferric thiocyanate method, and accelerated storage test in an oven) and high performance liquid chromatography analyses for identification of polyphenols. The mango flour showed high levels of carbohydrates, potassium, sodium, calcium and phosphorus, total phenolics, ascorbic acid and β-carotene. The factorial design defined as the ideal sequential extraction (80% methanol, followed by 80% acetone) and the following process conditions: temperature 37.5°C and 25ºC; time stirring of 30 and 60 min, whose extracts showed, respectively, higher total phenolic content (2407.16μg. mL-1) (Ext-5), and increased sequestration capacity DPPH (95%) (Ext-7). Both extracts exhibited significant antioxidant capacity against free radicals ABTS, DPPH and ORAC, and in lipid system. The chromatographic analysis revealed the presence in both extracts of the phenolic acids (benzoic acid and cinnamic acid derivatives), flavonoids and a xanthone, but with quantitative and qualitative differences between the profiles of the extracts. Synaptic acid, syringic acid, taxofoline, isoquercetine and mangiferin were the major constituents of these extracts. Thus, considering the chemical composition and antioxidant capacity, the agro-industrial waste of Tommy Atkins mango emerges as a potential source of natural antioxidant. / Este trabalho teve como objetivo caracterizar cascas liofilizadas de manga Tommy Atkins, provenientes de um cultivo orgânico, quanto à composição centesimal, de minerais, de fitoquímicos bioativos, e o potencial antioxidante além de definir as condições ideais para obtenção de extratos com elevado teor de polifenóis. As cascas liofilizadas foram trituradas, e a farinha submetida às determinações analíticas empregando-se técnicas titulométricas, espectrofotométricas e cromatográficas. Para definição das condições ideais de processo (tempo de agitação; temperatura e tipo de processo) aplicou-se o planejamento fatorial 2² , tendo como variáveis independentes: temperatura de 25 a 50°C e tempo de agitação de 30 a 90 min; e como resposta o teor de fenólicos e a capacidade de sequestrar o radical DPPH. O planejamento foi aplicado aos seguintes tipos de processo: a) Extração sequencial-solução hidroacetônica (80%), seguida da solução hidrometanólica (80%); b) Extração sequencial-solução hidrometanólica (80%), seguida da solução hidroacetônica (80%); c) Extração não sequencial-solução hidroacetônica (80%); d) Extração não sequencial-solução hidrometanólica (80%). Os extratos obtidos utilizando as condições ideais foram submetidos aos ensaios antioxidantes, de captura de radicais, em sistema modelo (DPPH; ABTS; ORAC) e aos ensaios antioxidantes em sistemas lipídicos (oxidação acoplada do B-caroteno/ácido linoléico; da peroxidação do acido linoleico – método tiocianato férrico; e do teste acelerado em estufa), e a cromatografia liquida de alta eficiência (HPLC) para identificação dos polifenóis. A farinha de manga apresentou elevados teores de carboidratos, potássio, sódio, cálcio e fósforo, fenólicos totais, ácido ascórbico e β-caroteno. O planejamento fatorial definiu como ideal a extração sequencial (metanol 80%, seguido por acetona 80%) e as seguintes condições de processo: temperatura de 37,5ºC e 25ºC e tempo de extração de 30 e 60min; cujos extratos apresentaram, respectivamente, maior teor de fenólicos totais (2407,16μg. mL-1) (Ext-5), e maior capacidade de sequestro do radical DPPH (95%) (Ext-7). Os dois extratos exibiram expressiva capacidade antioxidante frente aos radicais livres ABTS, DPPH e ORAC; bem como em meio lipídico. A análise cromatográfica revelou a presença, nos dois extratos, de ácidos fenólicos (derivados do ácido benzóicos e cinâmicos), flavonóides e uma xantona, porém com diferenças quantitativas e qualitativas entre os perfis dos extratos. O ácido siríngico, ácido sináptico, a taxofolina, a isoquercetina e a mangiferina foram os constituintes majoritários nestes extratos. Assim, considerando a composição química e a ação antioxidante, o resíduo agroindustrial de manga Tommy Atkins surge como uma fonte potencial de antioxidante natural.
83

Efeitos de ferimento, umidade e temperatura na virulência de espécies de Lasiodiplodia em frutos de manga

SILVA, Soraya de Lima e 12 February 2016 (has links)
Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-12-02T12:54:47Z No. of bitstreams: 1 Soraya de Lima e Silva.pdf: 781402 bytes, checksum: 6f6a41f42d5f65201486956ae0b36300 (MD5) / Made available in DSpace on 2016-12-02T12:54:47Z (GMT). No. of bitstreams: 1 Soraya de Lima e Silva.pdf: 781402 bytes, checksum: 6f6a41f42d5f65201486956ae0b36300 (MD5) Previous issue date: 2016-02-12 / Dieback and stem-end rot, caused by species of Botryosphaeriaceae, are important diseases of mango in the Brazilian Northeast. These diseases limit the production and drastically reduce fruit quality, directly affecting exports. In this study, was investigated the effects of wound, humidity and temperature in virulence of five Lasiodiplodia species prevalent in the orchards of northeastern Brazil (L. hormozganensis, L. iraniensis, L. pseudotheobromae, L. theobromae and L. viticola). Lasiodiplodia hormozganensis, L. pseudotheobromae and L. theobromae did not induce symptoms in non-wounded fruits, but all Lasiodiplodia species induced symptoms in wounded fruits. There were differences between species in relation to virulence levels both in the absence and in the presence of wound. The wound age in fruits influenced the virulence of Lasiodiplodia species of all species has expressed increased virulence when inoculated immediately after the wound, reducing the virulence with increasing wound age. Lasiodiplodia pseudotheobromae was the most sensitive species to the wound age. The high relative humidity length influenced the virulence of the Lasiodiplodia species, with an increase in virulence with the lifting of the period under high humidity. Lasiodiplodia hormozganensis, L. iraniensis and L. theobromae induced symptoms in the absence of high humidity. The virulence of Lasiodiplodia species was significantly influenced by the time interval between the inoculation and beginning of high relative humidity. All species expressed increased virulence when exposed to high relative humidity immediately after inoculation and decreased virulence with increasing time interval to beginning of high humidity. Lasiodiplodia iraniensis and L. viticola were the species most sensitive to the delay in onset of high relative humidity. No Lasiodiplodia species induced symptoms in fruit stored at 5 ° C and only L. pseudotheobromae induced symptoms at 10 ° C. There was no significant difference between species in relation to the optimum temperature for maximum virulence expression, ranging between 29.6 and 31.3 ° C. In most experiments, the increased virulence was demonstrated by L. iraniensis while L. viticola was less virulent. / A morte descendente e a podridão peduncular, causadas por espécies de Botryosphaeriaceae, são importantes doenças da mangueira no Nordeste brasileiro. Essas doenças limitam a produção e reduzem drasticamente a qualidade dos frutos, afetando diretamente a exportação. Nesse estudo, foi investigado o efeito de ferimento, umidade e temperatura na virulência de cinco espécies de Lasiodiplodia prevalentes em pomares de mangueira do Nordeste brasileiro (L. hormozganensis, L. iraniensis, L. pseudotheobromae, L. theobromae e L. viticola). Lasiodiplodia hormozganensis, L. pseudotheobromae e L. theobromae não induziram sintomas em frutos sem ferimento, mas todas as espécies de Lasiodiplodia induziram sintomas em frutos feridos. Houve diferença entre as espécies em relação aos níveis de virulência tanto na ausência como na presença de ferimento. A idade do ferimento nos frutos influenciou no nível de virulência das espécies de Lasiodiplodia e todas as espécies expressaram a maior virulência quando inoculadas imediatamente após a realização do ferimento, reduzindo a virulência com a elevação da idade do ferimento. Lasiodiplodia pseudotheobromae foi a espécie mais sensível à idade do ferimento. O tempo de duração da umidade relativa elevada influenciou na virulência das espécies de Lasiodiplodia, havendo um aumento na virulência com a elevação do período em umidade elevada. Lasiodiplodia hormozganensis, L. iraniensis e L. theobromae induziram sintomas na ausência de umidade elevada. A virulência das espécies de Lasiodiplodia foi influenciada significativamente pelo intervalo de tempo entre a inoculação e o início da umidade relativa elevada. Todas as espécies expressaram a maior virulência quando submetidas à umidade relativa elevada imediatamente após a inoculação e reduziram a virulência com o aumento do intervalo de tempo para início da umidade relativa elevada. Lasiodiplodia iraniensis e L. viticola foram as espécies mais sensíveis à demora para início da umidade relativa elevada. Nenhuma espécie de Lasiodiplodia induziu sintomas em frutos armazenados a 5 ºC e somente L. pseudotheobromae induziu sintomas a 10 ºC. Não houve diferença significativa entre as espécies em relação à temperatura ótima para expressão da máxima virulência, que variou entre 29,6 e 31,3 ºC. Na maioria dos experimentos, a maior virulência foi evidenciada por L. iraniensis, enquanto L. viticola foi a menos virulenta.
84

Diversidade genética molecular em germoplasma de mangueira / Molecular genetics diversity on Mango Tree Germplasm

Carlos Eduardo de Araujo Batista 17 December 2012 (has links)
A manga (Mangifera indica L.) é uma fruta tropical de origem no continente asiático e umas das principais frutas comercializadas no mundo. A mangicultura apresenta potencial para expandir ainda mais a comercialização de frutos e derivados principalmente, com qualidades para exportação. A produção mundial em média é de 27 milhões de toneladas. Os programas de melhoramento de mangueira necessitam desenvolver cultivares que apresentem o maior número de características agronômicas agregadas. O conhecimento da variabilidade e estrutura genética é almejado pelos melhoristas uma vez que a espécie é perene e apresenta longo o período para obtenção de novas cultivares. Neste trabalho, 151 acessos de mangueira foram analisados quanto a diversidade e estrutura genética do banco de germoplasma. Foram desenvolvidos 23 marcadores microssatélites para caracterização do banco de germplasma de mangueira. Os locos microssatélites apresentaram alto poder informativo para estudos populacionais e observaram-se médias da heterozigosidade esperada de He=0,655, heterozigosidade observada de Ho=0,496 e de PIC = 0,621. Posteriormente a partir dos dados moleculares foram estimados a diversidade e estrutura genética dos 151 acessos e observaram-se 144 alelos com média de 7,2 alelos por loco com amplitude entre 2 e 12 alelos, e uma diversidade gênica média de 0,689. Em todas as simulações estatísticas utilizadas houve consistência em se agrupar os acessos em dois grupos, um grupo formado pelos acessos brasileiros e outro com os acessos norte americanos e os novos híbridos. Uma coleção nuclear foi formada com 30 acessos conseguindo manter 100% dos alelos considerando a diversidade molecular dos 151 acessos de mangueira. Para disponibilizar mais informações ao banco de germoplasma de mangueira da EMBRAPA, 103 acessos contendo informações de 20 locos microssatélites e médias de 48 características agromorfológicas foram avaliadas em conjunto pelo método de otimização de Tocher e formaram-se 23 grupos, onde mais de 50% dos acessos formaram 22 grupos; destes, 10 grupos foram formados por acesso único. Com a finalidade de gerar mais informações para programas de melhoramento da mangueira, um teste de atribuição foi realizado a partir dos dados moleculares e fenotípicos qualitativos, em que também os acessos foram agrupados em dois grandes grupos. / The mango (Mangifera indica L.) is a tropical fruit of Asiatic origin and one of the main fruits traded worldwide. The mango crop presents a potencial for further expansion of fruits and derivative trades mainly export qualities. The average world production is 26 million tons. Breeding programs need to develop mango cultivars having the highest aggregate number of agronomic traits. Knowledge of both the genetic variability and structure is aimed by mango culture breeders due to perennial species as well as to the long period of time to obtain new cultivars. In this study, the genetic diversity and structure of the germplasm bank in 151 acessions of mango were analyzed. At first, 23 microsatellite markers were developed in order to extract molecular information from bank germplasm. It was possible to detect that the SSR loci were highly informative in the studied population. Averages were obtained of He = 0.655, Ho = 0.496 and PIC = 0.621. Next, with the molecular data it was possible to estimate the genetic diversity and structure of the 151 acessions as well as observe 144 alleles with an average of 7.2 per locus with amplitude between 2 and 12 alleles; the average gene diversity was 0.689. In all simulations there were consistent statistic analyzes enabling the clustering cultivars in two groups. A group was formed by Brazilian landraces and a second group was formed by North American landraces and Brazilian new hybrids. A core collection of 30 acessions was able to keep 100% of the alleles representing the molecular diversity of 151 mango cultivars. To provide more information to the Embrapa germplasm mango tree, 103 acessions containing information from 20 microsatellite loci and average of 48 agronomic traits were assessed together by the method of Tocher and formed 23 groups. Twenty two groups were formed by more than 50% of acessions while 10 groups were formed by a single acession each. An interactive test was conducted from molecular and qualitative phenotype data which resulted in two consistent clusters.
85

Néctar de manga (Mangífera indica L.) adoçado com diferentes edulcorantes : perfil sensorial descritivo, tempo-intensidade e estudos de consumidor / Mango nectar sweetened with high intensity sweeteners : descriptive sensory profile, time-intensity analysis and consumer research

Cadena, Rafael Silva, 1983 21 August 2018 (has links)
Orientador: Helena Maria André Bolini / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-21T16:30:20Z (GMT). No. of bitstreams: 1 Cadena_RafaelSilva_D.pdf: 521247 bytes, checksum: 6926f96ecbac6ea3d9d78e69251418c3 (MD5) Previous issue date: 2012 / Resumo: O consumo de frutas e vegetais tem sido associado com a baixa incidência de doenças degenerativas, pois efeitos protetores estão associados com componentes antioxidantes contidos nestes alimentos. Atrelado a isto, o mercado de sucos e néctares de frutas está sob um aumento significativo, o que tem atraído a atenção de agricultores, distribuidores e da indústria deste produto para saciar esta demanda. Entretanto, estes produtos estão associados à alta ingestão de sacarose proveniente da adição em sua elaboração, o que pode acarretar o desenvolvimento de doenças relacionadas ao consumo excessivo de calorias. A partir disto, este estudo objetivou analisar a aplicação de novos edulcorantes de em néctar de manga pelo estudo de perfil sensorial e físico-químico ao longo do tempo de estocagem. Neste estudo foram utilizadas amostras de néctar de manga elaboradas com polpa de manga congelada e água (1:1) adoçadas com sacarose, sucralose, estévia com 97% de rebaudiosídeo, neotame, blend acessulfame-K/sucralose/neotame (100:50:1) e blend taumatina/sucralose (1:1), totalizando 6 amostras. O perfil físico-químico foi determinado por meio da análise de pH, acidez titulável, cor (L*, a*, b*) e sólidos solúveis (ºBrix). A análise sensorial foi composta por testes descritivos, Análise Descritiva Quantitativa (ADQ) e Análise Tempo-intensidade, além de testes afetivos com escala hedônica e escala do ideal. Além destes, para o estabelecimento de equivalência de doçura foi utilizado o teste sensorial Estimação de Magnitude. A análise estatística foi composta por Análise de Variância (ANOVA), Teste de média de Tukey com nível de significância de 5% para as análises físico-químicas, ADQ, análise tempointensidade e teste afetivo com escala hedônica. O teste com escala do ideal foi analisado por distribuição em histogramas e os dados de estimação de magnitude utilizaram regressão linear em sua análise. Os provadores estabeleceram o valor de 6,8% de sacarose como a quantidade ideal para a intensidade de gosto doce. O neotame foi o edulcorante que apresentou maior poder adoçante, sendo 6026 mais doce que a sacarose, seguindo pela sucralose (627), blend taumatina/sucralose (549), blend acessulfame-K/sucralose/neotame (259) e estévia (134). Os testes físico-químicos e, em especial, a ADQ identificaram a sucralose como o edulcorante que melhor substituiu a sacarose, pois foi o aditivo que apresentou o menor número de diferenças em relação à amostra controle. A análise tempo-intensidade e os testes afetivos também identificaram a amostra sucralose com o melhor perfil relacionado ao estímulo gosto doce, com grande semelhança ao ocorrido com a sacarose e sendo esta a amostra com maior grau de aceitação no tempo zero e a única que se manteve desta forma após os 120 dias de estocagem. Em conclusão, a estévia apresentou melhorias em seu perfil quando comparadas a outros estudos, mas ainda abaixo do esperado para um substituinte de sacarose. A taumatina, uma proteína de origem vegetal apresentou bom perfil e é um aditivo que necessita de maiores estudos para melhoria de sua tecnologia. E, por fim, a sucralose, como já afirmado em outros trabalhos, é o edulcorante que melhor substitui a sacarose em sucos tropicais, sem sofrer alterações significativas após processamento térmico e ao longo do tempo de estocagem / Abstract: The consumption of fruits and vegetable has been associated with low incidence of degenerative diseases, because protective effects has been linked with antioxidant compounds contained in these foods. Attached to this, the consumer market of fruit juices and nectars under a significant increase, which has attracted the attention of producers of these products to satisfy this demand. However, these products are associated with the high ingestion of sucrose from de addition in the elaboration, which may result in the development of diseases associated with the high consumption of calorie. From that, this study aimed to analyze the application of high intensity sweeteners in mango nectar by the sensory and physical-chemical profile during the storage time. Mango nectar samples were prepared with unsweetened mango frozen pulp and water (1:1). The samples were sweetened with different high intensity sweeteners and sucrose. The sweeteners were: Neotame; Sucralose; Stevia with 97% of Rebaudioside; 1:1 Thaumatin/Sucralose blend; 100:50:1 Acesulfame-K/Sucralose/Neotame blend. The physical-chemical profile was determined by: pH, titratable acidity, color (L*, a*, b*), solids soluble (ºBrix). The sensory analysis was composed by descriptive analysis, Quantitative Descriptive Analysis (QDA) and Time-intensity Analysis (T-I), also consumer test with hedonic scale e just-about-right (JAR) scale. Magnitude estimation method was applied to establish the relative sweetness with sucrose. Statistical analysis was composed by analysis of variance and Tukey means test with 5% of significant level to physical-chemical, QDA, T-I analysis, and consumer test. The JAR scale test was analyzed by histograms distribution and the results of magnitude estimation method through linear regression. The ideal sweetness analysis revealed that 6.8% was the ideal concentration of sucrose in the mango nectar. The relative sweetness analysis showed that Neotame presented the highest sweetening power, being 6026 times sweeter than sucrose, followed by Sucralose (627), Thaumatin/Sucralose blend 1:1 (549), Acesulfame-K/Sucralose/Neotame blend 100:50:1 (259) and Stevia (134). The physical-chemical analysis and, in special, the QDA identified sucralose as the best sweetener which best sucrose substitutes, since this additive presented less differences in relation to control sample. T-I analysis and consumers test also identified the sample sucralose with best profile in relation to the sweet stimulus, with great similarity to control sample and being the sample with higher acceptability in initial time and the only one that has remained this way after 120 days of storage. In conclusion, the stevia presented improvements in its sensory profile when compared with others studies,although still lower than expected to a sucrose substitute. The thaumatin, a vegetal protein, presented good sensory profile and is a additive that requires more studies to improve its knowledges. The sucralose, as founded in other studies, is the sweetener that best replace sucrose in tropical fruit juice, with no significant change after heat treatment and during the storage time / Doutorado / Consumo e Qualidade de Alimentos / Doutor em Alimentos e Nutrição
86

Amélioration de la conservation des mangues 4ème gamme par application de traitements thermiques et utilisation d’une conservation sous atmosphère modifiée / Improving the storage of minimally processed mangoes (Mangifera indica L.) by hot water treatments and modified atmosphere packaging

Djioua, Tassadit 02 September 2010 (has links)
La conservation des mangues 4ème gamme est limitée par le brunissement enzymatique et la perte de fermeté dus aux différentes opérations de transformation. Cette thèse propose un nouvelle approche pour améliorer la conservation de mangues 4ème gamme : l’application de traitements thermiques par immersion et/ou la conservation sous atmosphère modifiée : passive ou active (5% O2 – 5 % CO2) ou des enrobages (chitosane). Ce travail a permis tout d’abord de déterminer un couple température / temps optimal: 50 °C / 30 min qui permet de maintenir la qualité de plusieurs variétés de mangue (Keitt, Kent, Tommy Atkins). Les effets du traitement thermique sur l’intensité respiratoire, la couleur, la fermeté, les teneurs en antioxydants : vitamine C, caroténoïdes et phénols totaux, et sur l’activité de plusieurs enzymes (pour la fermeté : PME, PG, b-GAL ; et pour la couleur : PPO et PAL) ont été étudiés. Ces travaux ont montré que durant 9 jours à 6 °C, le traitement thermique maintient principalement la couleur par réduction de l’activité de la PPO et réduit la perte en fermeté par réduction de l’activité des enzymes pectolytiques (PME et b-GAL). Par ailleurs, les atmosphères modifiées semblent moins efficaces pour le maintien de la couleur et de la fermeté des mangues 4ème gamme. L’association du traitement 50°C/ 30 min avec une conservation sous atmosphère modifiée apporte peu d’effets additionnels et a même parfois un effet inhibiteur / The storage of fresh-cut mangoes is limited by the enzymatic browning and the loss of firmness due to the various operations of process. This work proposes a new approache to improve the storage of fresh-cut mangoes by: application of heat treatments by dipping with, or not, a storage under modified atmosphere: passive or active (5% O2 - 5% CO2) or using coatings (chitosane). The first step of this work was to determine the traitement 50 °C/30 min as an optimal treatment which maintian the quality of several varieties of mango (Keitt, Kent, Tommy Atkins). Effects of the heat treatment on the respiratory intensity, the color, firmness, the contents antioxydants: vitamin C, carotenoids and phenols total, and on the activity of several enzymes (PME, PG, b-GAL: for firmness; and PPO and PAL for colour changes) were studied. This work showed that during 9 days at 6 °C, the heat treatment maintains mainly the color by reduction of the activity of PPO and reduces the loss in firmness by reduction of the activity of the pectolytic enzymes (PME et b-GAL). In addition, the modified atmospheres seem less effective for the maintenance of the color and the firmness of freshcut mangoes. Combination of heat treatment with a modified atmosphere storage and have less additional effects and has even sometimes an inhibiting effect
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Analyse expérimentale et modélisation de l’hétérogénéité de la qualité et de la maturité des mangues / Effects of environmental factors on the variability of mango quality and maturity, experimental and modelling approaches

Nordey, Thibault 09 December 2014 (has links)
La qualité du fruit regroupe un ensemble d’attributs, comme le calibre, la teneur en composés solubles, l’acidité et la couleur, qui varient en fonction des conditions de croissance rencontrées par le fruit pendant son développement et au cours de son murissement. Ce travail de thèse vise à déterminer, par des approches expérimentales et de modélisation, l’impact des conditions de croissance de la mangue sur les processus impliqués dans l’élaboration de sa qualité et de son murissement. Les approches expérimentales ont révélé d’importantes variations de calibre, masse sèche, et maturité entre les mangues selon leur position dans l’arbre et la charge en fruits. Nos mesures ont suggéré que la croissance des mangues est impactée par la diminution des flux de xylème causé par l’embolisation des vaisseaux conducteurs de sève. En plus des différences mesurées entre les fruits, nos résultats ont indiqué des variations de couleur de peau et de pulpe, d’acidité et de teneur en composés solubles au sein même des mangues qui s’expliquent en partie par les gradients de maturité. L’établissement d’un modèle thermodynamique a permis de montrer que les microclimats au sein de l’arbre génèrent un gradient de température au sein de la mangue qui varie en fonction de la position dans l’arbre. Il a été montré que ce gradient de température n’explique pas les variations d’acidité, de couleur de pulpe et de teneur en composés solubles au sein de la mangue. L’utilisation d’un modèle simulant la synthèse de l’éthylène dans la mangue a mis en évidence que les différences de maturité entre les mangues dans l’arbre s’expliquent davantage par les différences de disponibilité carbonée que par les différences de température. L’intégration des résultats expérimentaux dans un modèle de croissance en matière fraiche a permis de confirmer que l’embolisation des vaisseaux conducteurs de sève est à l’origine du ralentissement de croissance de la mangue. Enfin, le couplage de tous ces modèles à un modèle de croissance en matière sèche a montré que les variations de calibre, teneur en matière sèche et maturité entre les mangues ne sont pas causées par les différences de température, mais par les différences de charge en fruits, de période de floraison, de masse sèche des fruits à la fin de la division cellulaire, et de transpiration.L’approche pluridisciplinaire, i.e., physique, écophysiologique et biochimique, utilisée dans ce travail de thèse a permis d’acquérir de nouvelles connaissances sur l’élaboration de la qualité du fruit et son murissement et ouvre de nouvelles perspectives de recherche. / One of the major difficulties involved in marketing fresh mango is to manage its quality. Mango quality includes several attributes such as size, total soluble solids content, acidity and color, all of which vary with growing conditions and during ripening. The aim of this thesis is to determine the impact of growing conditions on fruit quality and ripening through experimental and modeling approaches.Experimental studies have revealed that size, dry mass and maturity vary considerably between mangoes according to their position in the tree and fruit load. Measurements suggest that fruit growth is affected by the embolization of sap-conducting vessels. In addition to differences measured between mangoes, our results showed that quality attributes vary within fruits in relation to the maturity gradient.A physical model showed that climatic variations within the tree caused substantial temperature gradients within mangoes that change with the fruit position in the tree. These simulations revealed that quality differences within mangoes are not related to the temperature gradient, except for fruit color. Use of a model that simulates the biosynthetic pathway of ethylene indicated that maturity differences between mangoes are explained by differences in carbon supply and, to a much lesser extent, to differences in temperature. The integration of experimental results into a growth model revealed that the embolization of sap-conducting vessels caused the slowdown of fruit enlargement. Lastly, when all of these models were coupled to a model that simulates fruit growth in dry mass, it was demonstrated that variations in size, dry matter content and maturity between mangoes were caused by differences in fruit load, flowering time, fruit dry mass at the end of cell division and transpiration, rather than by differences in temperature.The multidisciplinary approach developed made it possible to better understand the processes involved in fruit quality and ripening and to open new areas of research.
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Aspects of mango magnifera indica L. fruit rind morpgology and chemistry and their implication for postharvest quality

Du Plooy, Gertina Wilhelmina 18 January 2007 (has links)
As the second most popular fruit world-wide, cultivation of mangoes in South Africa is of strategic economic importance. Competitive export markets require horticultural practices that meet international regulations concerning cultivation, pest control and maintenance of fruit physiology during export. The implementation of such practices, however, cannot be cost effective and successful without detailed and scientific-based knowledge of the commodity concerned. This study of the epicuticular surface of mango fruit has described the ontogeny, morphology and some chemical aspects thereof. Contributions from this study include the following findings: -- Ontogeny and morphology of mango fruit wax: This study found that the highly intricate wax crystalloid structures were not strictly cultivar dependant. A complex series of events constitutes epicuticular wax development. The development of epicuticular crystalloids is accompanied by considerable changes in cutin and epidermal cell morphology. -- Morphology of mango lenticels: An unusual morphology with some cultivar dependent lenticel characteristics was described. Exhaustive past attempts at management of the manifestation of the economically important lenticel discolouration were placed in perspective by establishing the cosmetic nature of the condition. It was found that the density and distribution of epicuticular wax contribute to morphological characteristics of lenticels of individual cultivars. -- Chemical characterisation of mango fruit wax: The chemical complexity of the dual layered epicuticular wax of mango fruit was established by this study, and the validity of interchanging Raman spectroscopy and Fourier transform infrared spectroscopy as investigative techniques established. -- Chemical profiles of discolouring lenticels: The development of lenticel discolouration as a stress-related self-defence mechanism was shown through use of combined chemical and visualisation techniques. This study confirmed the superficial nature and self-defence role of discoloured lenticels. -- Impact of some pre- and postharvest practices on mango fruit wax: Not only postharvest, but also preharvest management of mango fruit must consider the epicuticular membrane as part of the fruit-atmosphere interface. Maintaining a balance between them depends on a better understanding of the interdependence of management and fructosphere dynamics. Both a preharvest and a postharvest practice were studied: ----- Preharvest treatment of mangoes with uncalcined kaolin. Sunburn is an economically important problem in all fruit and vegetable crops. This study has showed that solutions to contain the problem can, however, not be transferred between crops without scientific knowledge of the physiological impacts and long term repercussions thereof. ----- Effect of mechanical handling on the packline and commercial wax coating. Physical and chemical impacts from the packline bring about progressive, irreversible changes to the fruit epicuticular wax. To benefit from these changes, strict management and process control must be practiced. / Thesis (PhD (Plant Pathology))--University of Pretoria, 2007. / Microbiology and Plant Pathology / unrestricted
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Taxonomy and population genetics of Fusarium subglutinans sensu lato on pine and mango

Britz van Heerden, Henriette 30 November 2005 (has links)
Fusarium subglutinans sensu lato is a complex of fungi, which are the causal agents of important diseases on a wide variety of plants. Two important diseases caused by F. subglutinans sensu lato are pitch canker and mango malformation. F. subglutinans sensu lato isolates causing pitch canker on pine trees have been described as a separate species, F. circinatum. whereas F. subglutinans sensu lato isolates associated with mango malformation have not been formally described. The objective of study was to clarify the taxonomy and population genetics of the pitch canker and mango malformation fungi residing in the Gibberellafujikuroi complex. The introductory chapter of this thesis provides a review of the taxonomic classifications used for Fusarium spp. in the G. fujikuroi complex. In addition, the current knowledge pertaining to the population structure of the pitch canker and mango malformation fungi is discussed. In the second chapter the occurrence of F. circinatum was investigated in Mexico. Fusarium isolates were collected from pine trees in Mexico and identified as F. circinatum. Morphology, sexual compatibility studies, pathogenicity tests and histone H3-RFLPs were used to identify and characterize this fungus. The pitch canker fungus, F. circinatum and its teleomorph, G. circinata has been recently described. However, the name G. circinata is invalid, because insufficient information was provided to characterize the type specimen in the description. Additional information and a selection of F. circinatum isolates were, therefore, obtained and studies were undertaken in order to validate the description of G. circinata. The teleomorph G. circinata was validated and morphological criteria were shown to clearly distinguish F. circinatum from other F. subglutinans sensu lato isolates. Chapter four presents a study aimed at better understanding relationships between populations of F. circinatum from different geographical areas. For this study co¬dominant molecular markers were developed. These were then used to determine the genetic diversity, genetic distance and migration between different F. circinatum populations. Analysis revealed a high diversity in the Florida population and a low diversity in the South African population. Genetic analysis also indicated that the South African F. circinatum population originated in Mexico. In chapter five, the influence of sexual reproduction on the F. circinatum populations sampled over ten years in South Africa were studied. Sexual compatibility, vegetative compatibility and allelic diversity that were determined using polymorphic markers, developed in chapter four, were used. These results suggested that sexual reproduction is occurring more frequently in the more recently collected populations than in the initial population. Mango malformation is an important disease in mango growing areas. The study presented in chapter six indicated that this disease is associated with two distinct Fusarium spp. in the section Liseola. The two new Fusarium spp. are thus described as F. mangiferae and F. sterilihyphosum using morphological criteria In chapter seven, the distribution and vegetative compatibility of both F. mangiferae and F. sterilihyphosum was determined for the South Africa populations. Results revealed that each of these species differ in their distribution in South Africa. Vegetative compatibility tests also suggest that both species represent single genets in South Africa. Fusarium subglutinans sensu lato isolates associated with pme and mango are economically important fungi. The focus of the studies presented in this thesis has been on the taxonomy and population genetics of these fungi, with special reference to their occurrence in South Africa. Each of the chapters will contributes towards a better understanding of the taxonomy, population genetics and biology of these fungi. / Thesis (PhD)--University of Pretoria, 2006. / Microbiology and Plant Pathology / Unrestricted
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Caracterização sensorial por analise descritiva quantitativa e analise tempo-intensidade de suco e de polpa de manga (Mangifera indica L.) adoçados com diferentes edulcorantes / Sensory caracterization by descriptive quantitative analysis juice time-intensity and mango polp (Mangifera indica L.) sweteners with edulcorants differents

Umbelino, Daniela Cardoso 20 January 2005 (has links)
Orientador: Helena Maria Andre Bolini / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T01:42:25Z (GMT). No. of bitstreams: 1 Umbelino_DanielaCardoso_D.pdf: 782386 bytes, checksum: 767a9f1a7013380f7623fc5c2d178e79 (MD5) Previous issue date: 2005 / Resumo: O Brasil possui um grande potencial de produção de sucos de frutas tropicais, entre os quais destaca-se o suco de manga. Por outro lado, a preocupação com a saúde impulsionou a pesquisa e o desenvolvimento de alimentos de baixa caloria e adoçantes não calóricos. Os edulcorantes podem produzir características sensoriais indesejáveis, sendo necessário estudá-los, individualmente, no alimento ou bebida aos quais são adicionados. Este trabalho teve por objetivo estudar o comportamento do suco de manga concentrado e da polpa de manga congelada, ambos reconstituídos e adoçados com diferentes edulcorantes (mistura ciclamato/sacarina 2:1, aspartame, sucralose e extrato de folhas de estévia) e com sacarose, sob o ponto de vista físico-químico e sensorial. Foram realizadas determinações fisico-químicas (pH, acidez titulável, sólidos solúveis e totais, açúcares redutores e não-redutores, e cor), determinação de doçura equivalente, análise descritiva quantitativa (ADQ), análise tempo-intensidade (ATI) e análise de aceitação. Os dados obtidos na análise descritiva quantitativa, e os dados dos parâmetros obtidos nas curvas tempo-intensidade foram avaliados através de análise de variância (ANOVA), testes de médias de Tukey e análise de componentes principais (ACP). Todas as análises estatísticas foram realizadas utilizando-se o programa SAS. A concentração ideal de sacarose a ser adicionada ao suco e à polpa de manga foi de 8 e 7,5%, respectivamente. A estévia apresentou o menor poder edulcorante e a maior diferença de potência em suco e em polpa de manga. Os demais edulcorantes apresentaram comportamentos semelhantes em suco e em polpa de manga em relação ao poder edulcorante, sendo a maior potência exibida pela sucralose. Na análise descritiva quantitativa, a estévia caracterizou-se por apresentar níveis elevados de doçura residual, amargor e amargor residual. A análise tempo-intensidade avaliou os estímulos doce, amargo e sabor de fruta, em suco e em polpa de manga. Na análise tempo-intensidade, a estévia apresentou a maior intensidade máxima para os estímulos doce e amargo, e esta característica persistiu por um longo período, confirmando a presença de doçura e de amargor residual intenso na amostra. A sacarose caracterizou-se por apresentar gosto doce limpo, sem residual amargo. Em relação ao estímulo sabor de fruta, a sacarose exibiu a maior intensidade máxima, e o aspartame o maior tempo total de duração do estímulo, indicando potencialização do sabor de fruta por este edulcorante. O aspartame e a sucralose foram os edulcorantes, cujo comportamento sensorial mais se aproximou ao da sacarose, na análise descritiva quantitativa e na análise tempo-intensidade. As maiores médias de aceitação, em relação ao sabor e à impressão global, foram exibidas pelas amostras adoçadas com sacarose, aspartame e sucralose, indicado que a aceitação do produto está diretamente relacionada à intensidade de doçura residual, amargor e amargor residual presentes no produto / Abstract: Brazil has a great potential for tropical fruit juice production, amongst which mango deserves special attention. In addition concern about health given inpetus to research and development on low calorie foods and non-caloric sweeteners. Alternative sweeteners can produce a variety of indesirable sensory characteristics, it being necessary to study them individually in the specific food or beverage. The objective of this study was to sensorially evaluate, industrialized reconstituted mango juice and mango pulp, sweetened with various edulcorants (mixture of cyclamate/saccharin 2:1, aspartame, sucralose and stevioside leaf extract) and sucrose. Physicochemical (pH, titratable acidity, total and soluble solids, reducing and non-reducing sugars and colour) determinations were carried out and also sensory analysis such as ideal sweetness using the just-about-right scale, sweetness equivalents, quantitative descriptive analysis, time-intensity analysis and acceptability of the sweetened mango juice and pulp with sucrose and with the edulcorants cited above. The quantitative descriptive analysis, time intensity analysis and acceptance test data were evaluated by the analysis of variance (ANOVA), Tukey¿s Test and the principal component analysis. The statistical analysis was carried out using the SAS program. The optimum sucrose concentration was 8% in mango juice and 7.5% in mango pulp. The results showed that sucralose had the greatest potency amongst the four intensity sweeteners tested in mango juice and pulp, while stevia leaf extract exhibited the smallest. Stevioside leaf extract was characterized by a strong bitter taste, sweet aftertaste and bitter aftertaste in the quantitative descriptive analysis. Sweetness, bitterness and fruitiness were evaluated by time-intensity methodology for mango juice and pulp. Stevioside leaf extract time-intensity curves showed a significantly longer sweet and bitter aftertaste than other sweeteners. Sucrose displayed a clean sweet taste with no unpleasant aftertaste. Sucrose had a higher intensity of fruit flavor and aspartame elicited significantly longer persistence of fruitiness, suggesting an intensification effect. The sensorial profiles of aspartame and sucralose were similar to that of sucrose in the quantitative descriptive analysis and time-intensity analysis. The acceptance test showed that the formulations with sucrose, aspartame and sucralose were similar in all attributes and had the highest acceptability. This observation suggests that the acceptance of a sweetener is related to the intensity of sweet aftertaste, bitter and bitter aftertaste / Doutorado / Consumo e Qualidade de Alimentos / Doutor em Alimentos e Nutrição

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