Spelling suggestions: "subject:"brownian""
181 |
Qualidade de ameixas ‘Laetitia’ frigoconservadas e submetidas ao estresse inicial por baixo oxigênio, tratamento térmico e vapor de etanol / Quality of ‘Laetitia’ plums cold stored and submitted to initial low oxygen stress, heat treatment and ethanol vaporHeinzen, Angélica Schmitz 28 July 2016 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-02-27T14:30:45Z
No. of bitstreams: 1
PGPV16MA207.pdf: 1304865 bytes, checksum: 7b2854584ba3fabd5f5a4cf59285f1f4 (MD5) / Made available in DSpace on 2018-02-27T14:30:45Z (GMT). No. of bitstreams: 1
PGPV16MA207.pdf: 1304865 bytes, checksum: 7b2854584ba3fabd5f5a4cf59285f1f4 (MD5)
Previous issue date: 2016-07-28 / Capes / ‘Laetitia’ plums develop internal browning during cold storage. The severity of this disorder is associated with factors such as harvest time, storage time, and oxidative stress. The occurrence of this disorder and rapid ripening of fruits during storage are the main challenges after harvesting plums. Methods such as initial low oxygen stress (ILOS) and heat treatments and ethanol vapor application can be alternatives for controlling internal browning and delaying ripening of fruits. The aim of this study was to evaluate the effect of ILOS, heat treatments and ethanol vapor application on both ripening of fruits and internal browning in ‘Laetitia’ plums cold stored, as well as on the oxidative stress on fruit pulp tissues. The fruits used in the experiments were from commercial orchards located in the municipalities of Urubici, Santa Catarina, 2014/15 and 2015/16 seasons and Vacaria, Rio Grande do Sul, 2014/15. In experiment 1, the following treatments were evaluated: control, ethanol vapor application (0.15%), heat treatment (37ºC/24 h), heat treatment (40ºC/6 h), heat treatment (37°C/24 h) + ethanol vapor application (0.15%), and heat treatment (40ºC/6 h) + ethanol vapor application (0.15%). In experiment 2, the following treatments were evaluated: maintenance of the fruits for 48 h under environmental conditions (20°C ± 5°C/63% ± 2% RH), and five periods of ILOS (1.0 kPa O2) (0, 12, 24, 48, and 72 h) under environmental conditions. Each treatment was performed four times, and an experimental unit comprised 20 fruits. Fruits were
stored (1±0.2°C e 92±2% de RH) during 35 days. In experiment 1, heat treatment at both temperatures resulted in a lower incidence of internal browning. The combination of heat treatment at 40°C for 6 h plus ethanol vapor application reduced the ethylene production rate, severity of internal browning, concentration of phenolic compounds, and antioxidant activity. It also maintained greater flesh firmness and POD and SOD activities. In experiment 2, fruits from the treatments with ILOS, at 2014/15, showed lower ethylene production and respiratory rates, less internal browning, as well as greater SOD enzyme activity. Fruits that presented a reddish epidermis color and had a greater fruit compression force and flesh firmness during the 48 and 72 h of ILOS treatment. ILOS treatment for 12 and 24 h led to decreased H2O2 production and greater SOD activity. In fruits from 2015/16, ILOS treatment for 12 h provided greater fruit compression force and flesh firmness and lower ethylene production rate, with less internal browning, lipid peroxidation, and POD and SOD activities / Ameixas ‘Laetitia’ desenvolvem escurecimento de polpa durante o armazenamento refrigerado e a severidade do distúrbio está associada a fatores como ponto de colheita, tempo de armazenamento, estresse oxidativo, entre outros. A ocorrência deste distúrbio e o rápido amadurecimento dos frutos durante o armazenamento caracterizam os principais desafios para a pós-colheita de ameixas. Tratamentos como o estresse inicial por baixo oxigênio (ILOS), tratamento térmico e o etanol podem ser alternativas para o controle do escurecimento de polpa e retardo do amadurecimento dos frutos. O objetivo deste trabalho foi avaliar o efeito do estresse por baixo oxigênio, do tratamento térmico e da aplicação de vapor de etanol sobre o amadurecimento e o escurecimento de polpa em ameixas ‘Laetitia’ armazenadas sob refrigeração, bem como sobre o estresse oxidativo no tecido da polpa dos frutos. Os frutos foram provenientes de pomares comerciais situados nos municípios de Urubici, SC, nas safras 2014/15 e 2015/16, e Vacaria, RS, na safra de 2014/15. No experimento 1, os tratamentos avaliados foram controle, aplicação de vapor de etanol (0,15%), tratamento térmico (37ºC/24 h), tratamento térmico (40ºC/6 h), tratamento térmico (37°C/24 h) + vapor de etanol (0,15%) e tratamento térmico (40ºC/6 h) + vapor de etanol (0,15%). Para o experimento 2, os tratamentos avaliados foram manutenção dos
frutos em condições ambiente por 48 horas (20±5ºC/UR de 63±2%) e cinco períodos de ILOS (1,0 kPa O2) (0, 12, 24, 48, 72 horas) em condições ambiente. Cada tratamento foi composto de quatro repetições e unidade experimental constituída de 20 frutos. Os frutos foram armazenados (1±0,2°C e 92±2% de UR) durante 35 dias. No experimento 1 o tratamento térmico, em ambas as temperaturas, resultou em menor incidência de escurecimento de polpa. A combinação de tratamento térmico 40°C por 6 horas mais aplicação de vapor de etanol reduziu a taxa de produção de etileno, a severidade do escurecimento de polpa e a concentração de compostos fenólicos e atividade antioxidante e manteve maior firmeza da polpa e atividade da POD e SOD. No experimento 2 os frutos dos tratamentos com ILOS, safra 2014/15, apresentaram menor taxas de produção de etileno e respiratória e menor incidência de escurecimento da polpa, bem como maior atividade da enzima SOD. Os frutos com cor da epiderme menos vermelha e maior força para compressão do fruto e firmeza de polpa foram observados em ILOS por 48 e 72 horas. Menor quantidade de H2O2, e maior atividade da SOD foram obtidos nos tratamentos com ILOS por 12 e 24 horas. Em frutos da safra 2015/16, o tratamento com ILOS por 12 horas proporcionou maior força para compressão do fruto e firmeza de polpa e menor taxa de produção de etileno, incidência de escurecimento da polpa, peroxidação de lipídios e atividade da POD e SOD
|
182 |
Fatores pré e pós-colheita que afetam a qualidade do fruto durante o armazenamento de peras Conference e Alexander Lucas / Factors pre and post harvest that afects the quality of the fruits "Conferences" and "Alexandre Lucas"Hendges, Marcos Vinícius 30 April 2015 (has links)
Made available in DSpace on 2016-12-06T17:42:06Z (GMT). No. of bitstreams: 1
PGPV15DA017.pdf: 2167142 bytes, checksum: f46dc26724e5902a13e50a01c53ada5b (MD5)
Previous issue date: 2015-04-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Four experiments were conducted to evaluate the effect of 1-MCP in CS and CA, and the ULO storage on the sensory quality and incidence of physiological disorders in function of the maturation at harvest in pears Conference and Alexander Lucas harvested at three production location. The fruit harvest was carried out in the cities of Ravensburg (orchard 1) for both cultivars and Langenargen (Orchard 2) and Öhringen (orchard 3) only for Alexander Lucas . All locations are in the state of Baden-Württemberg, southwestern Germany. For the experiments 1, 2 and 3 the design was completely randomized in a factorial scheme five (storage conditions) for two (harvest maturity). Treatments were: cold storage (CS-21.0 kPaO2+0.03 kPa CO2), controlled atmosphere (CA-2 kPa O2 / <0.7 kPa CO2), CS with 1-MCP application (CS+1-MCP-300 nL L-1), CA with application of 1-MCP (CA+1-MCP) and ultra low oxygen (ULO, 0.7 kPa O2 /<0.7 kPa CO2) versus harvest 1 (05/09/2012; Streif index of 0.15, 0.12, 0.09 to 1, 2 and 3 orchards, respectively) and harvest 2 (18/09/2012; Streif index of 0.08; 0.06, 0.08 for orchard 1, 2 and 3, respectively). All treatments were stored at 0±0.1°C and 94±2% relative humidity. In the experiment 4 was added high CO2 treatment (CO2-2 kPa O2/CO2 3 kPa). After seven months of storage plus seven days at ambient conditions (20±2°C/60±5% RH) fruits were evaluated for sensory attributes of firmness, color of skin (h°), soluble solids (SS), titratable acidity (TA) and aromatic compounds aldehydes, alcohols and esters. In addition, it were measured production of ethylene, α-farnesene, 6-methyl-5-heptene-2-one and respiratory rate, phenolics, vitamin C of epidermis, scald and internal browning , percentage of fruit with cavities and rot, and mineral content. In general the best storage condition to Conference would be in CA+1-MCP in fruit picked with IS 0.08. This condition provides larger fruits with reduced scald index without internal browning, besides development of aromatic compounds. The storage of the fruits of Alexander Lucas for seven months plus seven days at room temperature is too long. All the storage conditions caused internal disorder. Nevertheless, there are indications of the best storage condition in CS+1-MCP in fruits picked with IS 0.08. In this condition beyond the larger return occurs in the production of volatile reduction in surface escaldaura and browning occurs and no appearance of cavities / Foram conduzidos quatro experimentos com o objetivo de avaliar o efeito do 1-MCP, em AR e AC, e do ULO sobre a qualidade sensorial e incidência de distúrbios fisiológicos, em função do estádio de maturação em peras Conference e Alexander Lucas colhidas em três locais de produção. A colheita dos frutos foi realizada nos municípios de Ravensburg (pomar 1), para ambas as cultivares e Langenargen (pomar 2) e Öhringen (pomar 3) somente para Alexander Lucas . Todos os municípios localizam-se no estado de Baden-Württemberg, sudoeste da Alemanha. Para os experimentos 1, 2 e 3 o delineamento utilizado foi o inteiramente casualizado em esquema bifatorial cinco (condições de armazenamento) por dois (pontos de maturação). Os tratamentos foram: atmosfera refrigerada (AR-21,0 kPa O2+0,03 kPa CO2), atmosfera controlada (AC-2 kPa O2/<0,7 kPa CO2), AR com aplicação de 1-MCP (AR*-300 nL L-1), AC com aplicação de 1-MCP (AC*) e ultra baixo oxigênio (ULO-0,7 kPa O2/<0,7 kPa CO2) combinados com colheita 1 (05/09/2012; índice de Streif (IS) de 0,15; 0,12; 0,09 para pomares 1, 2 e 3, respectivamente) e colheita 2 (18/09/2012; IS de 0,08; 0,06; 0,08 para pomares 1, 2 e 3, respectivamente). Todos os tratamentos foram armazenados a 0±0,1ºC e 94±2% de umidade relativa. Ao experimento 4 foi acrescida a condição de armazenamento alto CO2 (2 kPa O2/3 kPa CO2). Após sete meses de armazenamento mais sete dias em condições ambiente (20±2ºC / 60±5% de UR) os frutos foram avaliados no experimento 1 e 2 quanto às taxas de produção de etileno e taxa respiratória, acidez titulável (AT), sólidos solúveis (SS), firmeza de polpa, cor da epiderme (h°) e compostos aromáticos. No experimento 3 foi avaliado o índice de frutos com escaldadura superficial, produção de α-farneseno e 6-metil-5-hepteno-2-ona, compostos fenólicos, vitamina C da epiderme e no experimento 4 o índice de escurecimento da polpa, porcentagem de frutos com cavidades e com podridão e teor de minerais. De maneira geral, apesar da perda na eficácia do 1-MCP no retardo do amadurecimento para ambas cultivares com o atraso na colheita a melhor condição de armazenamento para cultivar Conference seria em AC* em frutos colhidos com IS 0,08 (colheita 2). Está condição proporciona frutos maiores, com menor índice de escaldadura, ausência de distúrbios internos e com desenvolvimento de compostos aromáticos. O armazenamento dos frutos de Alexander Lucas por sete meses mais sete dias em temperatura ambiente é muito longo, pois todas as condições de armazenamento causaram distúrbios internos. Apesar disso, há indícios de que a melhor condição para o armazenamento desta cultivar é AR* em frutos colhidos com IS 0,08 (colheita 2), já que, ocorre retorno na produção de aroma, redução na escaldaura superficial e do escurecimento da polpa, sem o aparecimento de cavidades
|
183 |
Fatores associados à manifestação do escurecimento de polpa em ameixas / Factors associated to the occurrence of flesh browning disorder in plumsEspíndola, Bruno Pansera 04 December 2012 (has links)
Made available in DSpace on 2016-12-08T16:44:43Z (GMT). No. of bitstreams: 1
PGPV12MA113.pdf: 776914 bytes, checksum: 1b2df461f65d8892e51fd73c7b41950d (MD5)
Previous issue date: 2012-12-04 / The aim of this study was to identify possible factors that influence the occurrence flesh browning incidence in Laetitia and Angeleno plums. Three experiments were conducted. The objective of the first experiment was to evaluate the influence of production site, maturity stages at harves, fruit mineral content and quality attributes on flesh browning incidence in Laetitia plums. The experiment followed a 2x3 factorial design, with two production sites (Vacaria-RS and Lages-SC) and 3 maturity stages (fruit with 25, 50 and 75% of epidermis surface covered with red color). Fruit were stored for 30 days 0.5˚C/95% RH. The aim of the second experiment was to evaluate the effect of different storages atmospheres, the treatment with 1-MCP and flesh mass loss induction (FMLI) on the flesh browning incidence, as well as the relationship between soluble minerals content and ripening attributes after storage with the flesh browning disorder. The treatments were air atmosphere (21 kPa 02 + 0.03 kPa CO2); 1 kPa 02 + 10 kPa CO2; 2 kPa 02 + kPa CO2; 2 kPa 02 + 2 kPa CO2 with FMLI; 2 kPa 02 + 2 kPa CO2 with 1-MCP application. The fruit were stored at 0.5˚ C and 95% RH (except for FMLI treatment), and analyzed after 30 and 50 days of storage, at removal from cold storage and after 4 days at 20˚C. The third experiment was carried out to evaluate the effect of ethylene on flesh browning disorder in Laetitia and Angeleno plums. The treatments were control and 1-MCP at the dose of 1.0 µL L-1 in laetitia , and control and ethylene application at the concentration of 5.0 µL L-1 for Angeleno . Fruit from Vacaria showed lower flesh browning incidence and severity. Fruit with 75% of skin red color had higher flesh browning incidence and severity rhan fruits with 25% of skin red color. Fruit from vacaria had higher Ca and N contents and higher Ca/N ratio. Fruit stored in air atnomphere and 1kPa 02 + 10 kPa CO2 had the highest flesh browning incidence and severity. The highest ethylene production rate were observed in fruit stored in air atmosphere for 30 days, and in fruit stored in 1 kPa 02 + 10 kPa CO2 for 50 days. The flesh browning incidence was reduced in fruit treated with 1-MCP and left in 2 kPa 02 + 2 kPa CO2. The treatment with 1-MCP delayed ripening and reduced the occurrence of flesh browning in Laetitia plums. The treatment with exogenous ethylene accelerated the ripening and increased the flesh browning incidence in Angeleno plums. In conclusion, the occurrende of flesh browning is associated with a combination of factors. Fruit mineral content, ripening process, and inadequate storage conditions are involved in the flesh browning occurrence. The storage condition with 2 kPa 02 + 2 kPa CO2 associated to fruit treatment with 1-MCP reduces the occurrence of the disorder / O objetivo desse trabalho foi identificar possíveis fatores que influenciam a ocorrência de escurecimento de polpa em ameixas Laetitia e Angeleno . Foram realizados três experimentos, sendo o objetivo do primeiro avaliar a influência do local de produção, estádios de maturação na colheita, o teor mineral dos frutos e atributos de qualidade na manifestação do distúrbio escurecimento de polpa em ameixas Laetitia . O experimento constituiu de um fatorial 2x3, sendo dois locais de produção (Vacaria-RS e Lages-SC) e três estádios de maturação (frutos com 25, 50 e 75% da epiderme coberta com a coloração vermelha). Os frutos foram armazenados por 30 dias a 0,5°C / UR 95%. O segundo experimento teve como objetivo avaliar o efeito de diferentes atmosferas de armazenamento, a aplicação de 1-metilciclopropeno (1-MCP) e indução de perda de massa fresca (IPMF), na ocorrência do escurecimento de polpa, bem como se existe relação da manifestação do distúrbio com atributos minerais solúveis e de amadurecimento após o armazenamento. Os tratamentos foram atmosfera do ar (21 kPa O2 + 0,03 kPa CO2); 1 kPa O2 + 10 kPa CO2; 2 kPa O2 + 2 kPa CO2; 2 kPa O2 + 2 kPa CO2 com IPMF e 2 kPa O2 + 2 kPa CO2 com a aplicação de 1-MCP. A temperatura de armazenamento foi de 0,5°C e uma umidade relativa de 95%, exceto para IPMF, e os períodos de análise foram aos 30 e 50 dias de armazenamento, na saída da câmara e após quatro dias em condições ambiente. O terceiro experimento teve como objetivo avaliar o efeito do etileno na manifestação do escurecimento de polpa em ameixas Laetitia e em Angeleno . Os tratamentos avaliadosforam controle e aplicação de 1-MCP na dose de 1,0 μL L-1 em Laetitia e controle e aplicação de etileno na concentração de 5,0 μL L-1 para Angeleno . Frutos provenientes de Vacaria apresentaram menor incidência e severidade de escurecimento de polpa. Frutos com maturação de 75% apresentaram maior incidência e severidade de escurecimento de polpa que frutos com 25% de cor vermelha. Quanto aos teores minerais totais, Vacaria apresentou maiores conteúdos de Ca e N e maior relação Ca/N. Os tratamentos atmosfera do ar e 1 kPa O2 + 10 kPa CO2 apresentaram maior incidência e severidade de escurecimentode polpa. As taxas de produção de etileno foram superiores nos tratamentos atmosfera do ar aos 30 dias, mantendo-se a mais elevada junto ao tratamento 1 kPa O2 + 10 kPa CO2aos 50 dias. A ocorrência de escurecimento de polpa foi menor no tratamento 2 kPa O2 + 2 kPa CO2 + 1-MCP. A aplicação de 1-MCP retardou o amadurecimento e reduziu a ocorrência de escurecimento de polpa em ameixas Laetitia . O tratamento etileno exógeno acelerou o processo de amadurecimento e aumentou a ocorrência de escurecimento de polpa em ameixas Angeleno . Pode-se concluir que a manifestação do escurecimento de polpa está associada a uma combinação de fatores, sendo que o teor mineral e o processo de amadurecimento estão envolvidos na ocorrência do escurecimento de polpa e condição inadequada de armazenamento também pode estimular o distúrbio. A condição de 2 kPa O2 + 2 kPa CO2 com a aplicação de 1-MCP proporciona baixa ocorrência do distúrbio
|
184 |
Estudo das intera??es polifenol-prote?na e das rea??es de escurecimento n?o-enzim?tico para o processamento de caju?naDamasceno, Leandro Fernandes 15 June 2007 (has links)
Made available in DSpace on 2014-12-17T15:01:12Z (GMT). No. of bitstreams: 1
LeandroFD.pdf: 1531484 bytes, checksum: 8c328385e5fe3dc7294b86f55a82c108 (MD5)
Previous issue date: 2007-06-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The cashew, a fruit from Brazilian Northeast is used to produce juice due to its flavor and vitamin C richness. However, its acceptance is limited due to its astringency. Caju?na is a derivate product appreciated by its characteristic flavor, freshness and lack of astringency, due to tannin removal. Caju?na is a light yellow beverage made from clarified cashew juice and sterilized after bottling. It differs from the integral and concentrated juice by the clarification and thermal treatment steps. Many problems such as haze and excessive browning could appear if these steps are not controlled. The objective of this work was divided into two stages with the aim to supply process information in order to obtain a good quality product with uniform characteristics (sensory and nutritional). Polyphenol-protein interaction was studied at the clarification step, which is an empirical process, to provide values on the amount of clarifying solution (gelatin) that must be added to achieve a complete juice clarification. Clarification essays were performed with juice dilutions of 1:2 and 1:10 and the effect of metabissulfite and tannic acid addition was evaluated. It was not possible to establish a clarification point. Metabissulfite did not influenced the clarification process however tannic acid addition displaced the clarification point, showing the difficulty visual monitoring of the process. Thermal treatment of clarified juice was studied at 88, 100, 111 e 121 ?C. To evaluate the non-enzymatic browning, vitamin C, 5-hidroximetilfurfural (5-HMF) and sugar variation were correlated with color parameters (reflectance spectra, color difference and CIELAB). Kinetic models were obtained for reflectance spectra, ascorbic acid and 5-HMF. It was observed that 5-HMF introduction followed a first order kinetic rate at the beginning of the thermal treatment and a zero order kinetic at later process stages. An inverse correlation was observed between absorbance at 420 nm and ascorbic acid degradation, which indicates that ascorbic acid might be the principal factor on caju?na non-enzymatic browning. Constant sugar concentration showed that this parameter did not contribute directly to the nonenzymatic browning. Optimization techniques showed showed that to obtain a high vitamin C and a low 5-HMF content, the process must be done at 120 ?C. With the water-bath thermal treatment, the 90 ?C temperature promoted a lower ascorbic acid degradation at the expense of a higher 5-HMF level / O caju, frut?fera origin?ria do Nordeste brasileiro ? utilizado para produ??o de suco devido ao seu sabor e ser rico em vitamina C. Entretanto, sua aceita??o ? limitada devido a
sua adstring?ncia. Um produto bastante apreciado pelo seu sabor caracter?stico, refrescante e n?o adstringente, devido ? remo??o dos taninos, ? a caju?na. A caju?na ? uma bebida
elaborada a partir do suco de caju clarificado e esterilizada no interior de garrafas, apresentando uma colora??o amarelo-?mbar. Ela diferencia-se dos sucos de caju integral e
concentrado por meio das etapas de clarifica??o e tratamento t?rmico. Uma s?rie de problemas como turva??o e escurecimento excessivo do produto, pode aparecer se estas
etapas n?o forem bem controladas. O objetivo deste trabalho foi dividido em duas etapas, mas com o mesmo prop?sito de fornecer subs?dios que possibilitem o controle do processo de
maneira a se obter um produto de qualidade, com caracter?sticas mais uniformes (em termos sensoriais e nutricionais). Na clarifica??o, por se tratar de um processo emp?rico, buscou-se o entendimento das intera??es polifenol-prote?na para fornecer valores adequados de solu??o de
clarificante (gelatina) necess?ria para promover a clarifica??o completa do suco. Realizaramse ensaios de clarifica??o com suco de caju dilu?do nas propor??es 1:2 e 1:10 e avaliou-se a
influ?ncia da adi??o de metabissulfito e ?cido t?nico ao suco. Pelas t?cnicas utilizadas n?o foi poss?vel determinar um ponto de clarifica??o completa do suco de caju. O metabissulfito n?o
influenciou o processo de clarifica??o enquanto que adi??o de ?cido t?nico deslocou o ponto de clarifica??o, mostrando a dificuldade da observa??o deste ponto pelo operador. O efeito do tratamento t?rmico no suco clarificado foi estudado nas temperaturas de 88, 100, 111 e 121 ?C. Para avaliar o escurecimento n?o-enzim?tico, a varia??o de vitamina C, 5-
hidroximetilfurfural (5-HMF) e a??cares foram correlacionados com par?metros colorim?tricos (espectro de reflect?ncia, diferen?a de cor e CIELAB). Modelos cin?ticos foram obtidos para a mudan?a no espectro de reflect?ncia, ?cido asc?rbico e 5-HMF. A forma??o de 5-HMF seguiu dois mecanismos cin?ticos: taxa cin?tica de primeira ordem no come?o do tratamento t?rmico e taxa cin?tica de ordem zero em um per?odo mais avan?ado do processo. Observou-se correla??o inversa da absorb?ncia a 420 nm e a perda de ?cido
asc?rbico, o que indica que o ?cido asc?rbico pode ser o fator principal que causa o escurecimento da caju?na. A concentra??o constante dos a??cares mostrou que eles n?o
influenciaram diretamente o escurecimento n?o-enzim?tico. T?cnicas de otimiza??o mostraram que para se obter uma caju?na com concentra??o elevada de vitamina C e baixo
teor de 5-HMF, o tratamento t?rmico deve ser realizado a 120 ?C. No caso da utiliza??o de banho-maria para o tratamento t?rmico, a temperatura de 90 ?C promove uma menor
degrada??o de ?cido asc?rbico ? custa de um ?ndice de 5-HMF mais elevado
|
185 |
Respostas fisiológicas e bioquímicas de diferentes cultivares de batatas ao processamento mínimo / Physiological and biochemical responses of different potato cultivars to minimal processingMaria Carolina Dário Vitti 28 August 2007 (has links)
O presente trabalho teve como objetivo avaliar aspectos fisiológicos e bioquímicos de batatas cv. Ágata, Asterix e Monalisa minimamente processadas. Primeiramente foram estudadas variáveis fisiológicas e microbiológicas de batatas armazenadas a 5, 15 e 25ºC. As batatas \'Asterix\' apresentaram as maiores taxas respiratórias em relação a \'Ágata\' e \'Monalisa\', independente da temperatura de armazenamento. As contagens de bactérias psicrotróficas e coliformes totais, para todas as cultivares armazenadas a 5oC durante 9 dias de armazenamento, mantiveram-se dentro dos padrões aceitáveis. O armazenamento a 5oC foi eficiente no controle da atividade metabólica e na segurança de batatas minimamente processadas. No segundo experimento, o ensaio enzimático realizado teve como objetivo verificar o efeito de diferentes cultivares e de temperaturas de armazenamento (5 e 15ºC) sobre a atividade das enzimas fenilalanina amônia-liase (PAL), polifenoloxidase (PPO) e peroxidase (POD). As atividades enzimáticas aumentaram para todas as cultivares na temperatura de 15ºC. Batatas \'Ágata\' e \'Asterix\' são mais indicadas para processamento mínimo do que \'Monalisa\', sendo esta mais susceptível ao escurecimento enzimático. O terceiro experimento avaliou os níveis de carboidratos não estruturais em batatas minimamente processadas e armazenadas a 5 e 15ºC. A maior degradação de amido em batatas \'Asterix\' armazenadas a 5ºC esteve relacionada com o aumento do teor de açúcares solúveis verificado para este tratamento. Foi observado um aumento nos teores de amido para a cultivar \'Ágata\' armazenada a 5ºC. Os teores de sacarose decresceram para todas as cultivares armazenadas a 5ºC e houve manutenção nos teores deste carboidrato quando armazenadas a 15ºC. No quarto experimento foram testadas diferentes combinações de antioxidantes nas três cultivares armazenadas a 5ºC. Batatas \'Monalisa\' apresentaram os maiores teores de fenóis totais e valores de atividade da PAL, POD e PPO independente do tratamento. Batatas \'Ágata\' tratadas com ácido ascórbico 2% + cisteína 0,5% e cisteína 0,5% + 4-hexilresorcinol 0,01% apresentaram os menores valores de atividade da PAL, POD e PPO. Para as cultivares Asterix e Monalisa os melhores resultados obtidos foram nas combinações com 4-hexilresorcinol e cisteína, respectivamente. / The purpose of the present work was to evaluate physiological and biochemical aspects of minimally processed Agata, Asterix and Monalisa potato cultivars. First physiological and microbiological variables of fresh-cut potatoes stored at 5, 15 and 25ºC were evaluated. Potatoes \'Asterix\' showed the highest respiratory rates when compared to potatoes cv. Agata and Monalisa, regardless of the storage temperature. Psychrotrophic bacteria and total coliforms counts were within acceptable limits for all cultivars stored at 5oC during 9 days of storage. Storage at 5oC was effective to control the metabolic activity and to keep food safety of minimally processed potatoes. In a second experiment, the effect of different cultivars and storage temperatures (5 and 15ºC) on the enzymatic activity of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) was studied. Enzymatic activity increased in all cultivars at 15ºC. \'Agata\' and \'Asterix\' potatoes were more suitable for minimal processing than \'Monalisa\'. This last cultivar is more susceptible to enzimatic browning. The third experiment was aimed at evaluating non-structural carbohydrates levels in mimally processed potatoes stored at 5 and 15ºC. The highest starch degradation rate was observed in potatoes \'Asterix\' stored at 5ºC, which was related to the increase in the soluble sugar amount verified in this experiment. There was an increase in starch content in \'Agata\' potatoes stored at 5ºC. Sucrose contents decreased in all cultivars stored at 5ºC and remained constant in cultivars stored at 15ºC. In a fourth experiment, different combinations of antioxidants in the three potato cultivars stored at 5ºC were studied. Potatoes \'Monalisa\' showed the highest total phenol amounts and the highest activities of PAL, PPO and POD, regardless of treatment. \'Agata\' potatoes treated with ascorbic acid 2% + cysteine 0.5% and cysteine 0.5% + 4-hexylresorcinol 0.01% showed the lowest valves activities of PAL, POD and PPO. For the Asterix and Monalisa cultivars, the best results were obtained when combinations of 4-hexylresorcinol and cysteine were used, respectively.
|
186 |
Expressions of White Ink: Victorian Women's Poetry and the Lactating BreastMacDonald, Anna January 2015 (has links)
The period spanning from the late 1850s to the mid-1860s frames a historical moment in Victorian England when lactation and breastfeeding came under intense public scrutiny in both medical and creative writing. While popular domestic author Isabella Beeton wrote on the dangers that an unwary mother’s milk represented for her child and herself in her serial publication, Mrs. Beeton’s Book of Household Management (1859-1861), prominent physicians C.H.F. Routh and William Acton launched a public dispute in medical journals contesting the physiological and moral dangers that the fallen wet nurse posed for the middle-class household (1859). Meanwhile, the medical community catalogued the bizarre long-term physical and dispositional side-effects of an infant’s consumption of “bad milk” – among them, syphilis, swearing, sexual immorality, and death (Matus 161-162). But it is not only medical writers who were latching on to the breastfeeding debate as a means of voicing social and political concerns of the day; recent literary critics have gestured towards the troubling manifestations of lactation in popular mid-century novels like Charles Dickens’s Dombey and Son (1848) and George Eliot’s Adam Bede (1859) as entry points into Victorian anxieties about classed and gendered embodiment. This project stipulates that the mid-century preoccupation with managing women’s milk represents an intersection of two overlapping cultural paradigms pertaining to female expression: a cultural devaluation of female physiological expression as unconscious if not dangerous leakage, and a deprecation of female linguistic and poetic expression as an analogously unmeditated and potentially disruptive kind of communication. Mid-century manuals, articles, and novels offered public voice to a number of existing anxieties surrounding breastfeeding which accompanied the mid-nineteenth century, a historical moment at the cusp of a waning popularity in wet nursing and at the advent and rise of patented infant formula. This project stipulates that at least three female poets of the mid-nineteenth century employ lactation imagery in their works as a means of recasting a cultural devaluation of female expression – inventing a new critical terminology of feminine poetic signifiers that uses the symbolic medium of breastmilk as its ink. Informed by the medical and cultural context of the High Victorian age, I explore how poets Elizabeth Barrett Browning (1806-1861), Christina Rossetti (1830-1894), and Augusta Webster (1837-1894) not only participate in the preoccupation with unstable bodies and fluids, but capitalize on female leakage in an elaborate rhetorical strategy that embarks on a new embodied female poetics. Barrett Browning’s Aurora Leigh, Rossetti’s “Goblin Market,” and Webster’s Mother and Daughter all enlist the lactating and feeding breast in a series of elaborate metaphors of female identity construction, literary expression, and poetic voice.
|
187 |
Medusa's Metamorphosis In Victorian Women's Art and PoetryMcConkey, Emily 08 November 2021 (has links)
This thesis examines the figure of Medusa in the works of three Victorian women: the poets Elizabeth Barrett Browning (1806-1861) and Christina Rossetti (1830-1894), and the artist Evelyn De Morgan (1855-1919). For many in an era that sought to categorize women according to rigid social boundaries, Medusa embodied all that is suspicious, dangerous, and alluring about women. But in subtle and unexpected ways, these three women reimagined the Medusa archetype and used it to explore female experience and expression, as well as the challenges and complexities of female authorship. In their works, Medusa, like other hybrid personae such as the mermaid and the lamia, became a figure through which to explore liminal spaces and slippery categories. I argue that these women prefigured the twentieth-century feminist rehabilitation of Medusa. I also suggest that this proto-feminist transformation of the myth draws, directly and indirectly, from the tradition of Ovid, the first poet to suggest that Medusa’s monstrosity resulted from her victimhood and that her power is not merely destructive, but also creative. My analysis contends that, contrary to common understanding, women were revisioning Medusa’s meaning well before the twentieth century.
|
188 |
Effect of pH, Fat Level, and Various Browning Agents on Composition, Color, Texture, and Sensory Characteristics of Dark-Cutting Beef PattiesMoiseev, Igor V. 01 May 1997 (has links)
Extra lean (3.3% fat) and lean (20.0% fat) hamburgers in three pH groups (≤ 6.0; 6.01-6.49; 6.50-6.92) were evaluated for cooking-temperature profile, total process lethality, and physical properties after cooking to 71°C by double-side frying on an electric grill. Neither cooking-temperature profile nor cooking time was affected by hamburger fat content or pH. Double-side frying to 71.1°C internal temperature was adequate for more than 6-log destruction of viable E. coli O157:H7 and Salmonella at the geometrical center of extra lean and lean hamburgers. The coldest spot was on the circumferential surface, as indicated by the presence of a red ring of undenatured myoglobin, and confirmed by the finite-element temperature distribution model.
The effect of pH (5.80, 6.29, 6.73) on myoglobin denaturation in extra lean (3.3% fat) and lean (20.0% fat) hamburgers was studied. Compared to normal meat (pH= 5.8), raw extra lean ground beef of pH = 6.73 had significantly lower oxidation-reduction potential (ORP) value, lower concentration of metmyoglobin after 48 hr of refrigerated storage, and more distinct cherry-red color. Percent of myoglobin denaturation during cooking was affected mainly by pH and was not affected by total pigment or fat content of hamburgers. A pH ≥ 6.5 and ORP ≤ -200 mV were characteristic of dark-cutting beef
In a third experiment, extra lean (3.5%) and lean (20.0%) beef patties were made from normal beef (pH= 5.70) and dark-cutting beef (pH = 6.60). Controls were made with no additives or with 1% salt and 10% added water. Various browning agents (1% glucose, 0.2% caramel colorant, 0.3% calcium peroxide, or 2.5% encapsulated lactic acid) were added with 10% water and 1% salt. Salt had a pronounced prooxidant effect on myoglobin. Distinctive absorption peaks at 541-548 nm and 577-582 nm indicated that the undenatured pigment in cooked patties was oxymyoglobin. Dark-cutting patties had more rubbery texture and slightly perceptible off-flavor. Patties with lactic acid were less juicy and had lower intensity of beef flavor than other patties, and moderate intensity of sour off-flavor. Addition of salt and encapsulated lactic acid to beef patty formulation could solve the problem of hard-to-cook patties.
|
189 |
Modelling the Effects of Climate Change on Future DOC Export to Lake Mälaren Using a Generalized Watershed Loading Functions (GWLF) Model / Modellering av effekterna från klimatförändringar på framtida löst organiskt kol (DOC) export till Mälaren med hjälp av en GWLF-modellLindqvist, Klara January 2022 (has links)
Browning of boreal freshwaters due to an increased export of terrestrial dissolved organic carbon (DOC) has been observed for some decennia. Drivers include recovery from acid deposition and changing climate and land cover. Lake Mälaren provides the Swedish capital Stockholm with drinking water and an increased future browning of the lake could demand more treatment to produce acceptable drinking water. Knowledge of what can be expected in a changing climate is therefore needed. The aim of this study was to evaluate; (1) The performance of the GWLF model simulations of hydrology and DOC export for 13 catchments draining into the Galten and Ekoln basins in lake Mälaren; (2) How simulated DOC export from the 13 catchments would change in response to climate scenarios RCP2.6, 6.0 and 8.5; and (3) If climate change impact on DOC export to lake Mälaren potentially will demand more treatment of the lake water in the future to produce acceptable drinking water to the Stockholm area. All data used were open access and include temperature, precipitation, discharge, total organic carbon (TOC) and water colour, land cover and soil types. In comparison to other studies, good model performance was found when simulating daily streamflow, baseflow, surface runoff, daily DOC loads and monthly DOC loads. Model simulations of DOC concentrations were less certain, but for some catchments similar results were obtained as in other studies. Increased air temperature resulted in higher simulated soil temperatures and a longer growing season. An increase in both annual precipitation and evapotranspiration resulted in only slight increase in simulated annual streamflow. There were, however, large seasonal impacts on streamflow with higher winter flows and lower spring flood. Annual DOC loads increased, mainly due to increased DOC concentrations over the whole year, as the annual streamflow did not change greatly. Increased winter streamflow and DOC concentrations resulted in large increases in DOC loads. The impact was larger for the higher emission scenarios. DOC loading to Galten and Ekoln increased in all future scenarios during winter, with a likely impact on DOC concentrations in the eastern basins as well. Increased loads to Ekoln are likely to impact the drinking water production of Stockholm more direct than the increases in Galten, as the Ekoln water has a shorter transit time to the drinking water withdrawals. The GWLF model shows much promise in predicting DOC concentrations and loads to lake Mälaren in a changing climate. To estimate the effects of DOC export to lake Mälaren on future drinking water production, further work also needs to be done on in-lake transport and processes. / Sjöar och vattendrag på nordliga breddgrader har under flera decennier blivit allt brunare. Orsaken är att löst organiskt kol, Dissolved Organic Carbon (DOC), som bland annat utgörs av humusämnen, transporteras till ytvatten från omkringliggande mark. De vanligaste förklaringarna till detta är en återhämtning från tidigare försurning orsakad av sulfatdeposition, klimatförändringar och en ändrad markanvändning. Mälaren är den primära dricksvattenkällan för Stockholm och om vattnet fortsätter bli brunare kan det innebära att reningsprocessen behöver ändras för att undvika produktion av hälsofarliga biprodukter i dricksvattnet. Det är därför viktigt att ta reda på hur ett ändrat klimat kan påverka export av DOC till Mälaren. Målet med den här studien var att undersöka tre frågor kopplade till framtida DOC i Mälaren. Den första var hur väl GWLF-modellen kunde användas på 13 avrinningsområden i Mälaren. Modellen simulerar vattnets väg från nederbörd till vattendrag samt hur DOC bryts ned och transporteras ut från marken. Den andra frågan var hur simulerad nedbrytning och export av DOC skulle påverkas av tre olika klimatscenarion, Representative Concentration Pathways (RCP), som baseras på tre olika nivåer av utsläpp av växthusgaser. Dessa var RCP2.6, 6.0 och 8.5, där högre nivåer av utsläpp av växthusgaser är kopplade till en högre siffra. Den tredje och sista frågan var att utvärdera om klimatförändringar kommer påverka hur mycket DOC som når Mälaren och ifall detta kan väntas påverka framtida dricksvattenproduktion i området. All data som har använts för att genomföra studien har varit så kallad “Öppna data”, som är fritt för alla att ladda ned, från både svenska, europeiska och andra internationella databaser. Data som använts är temperatur, nederbörd, vattenflöde, vattenkemi, vegetationstäcke och jordarter. Modellen visade ett tillfredsställande resultat i att simulera dagligt vattenflöde och både daglig och månatlig DOC-export. Den var mer osäker på att simulera koncentrationerna av DOC, men i flera områden lyckades den prestera liknande som i många andra studier. Alla framtida klimatscenarier visade en ökning av nederbörd, luft- och marktemperatur, avdunstning och antal växtdagar. Det syntes en större påverkan vid högre utsläppscenarion och effekterna ökade för RCP6.0 och 8.5 mot slutet av detta sekel. För RCP2.6 kunde en återhämtning ses mot slutet av seklet på grund av en minskning av utsläpp av växthusgaser. Den högre årsnederbörden resulterade inte i motsvarande ökning i årsvattenflöde på grund av att även avdunstningen ökade. Simuleringen visade en säsongsbunden effekt på DOC-export med en ökning under vintermånaderna men ingen skillnad under sommaren. Koncentrationer av DOC ökade däremot under hela året, dock mer under vintern. Årsexport av DOC från de undersökta avrinningsområdena till de två bassänger i Mälaren som mottar vattnet, Galten och Ekoln, ökade för alla framtida klimatscenarion. Ökningen var ett resultat av ökad vinterexport då det under sommarmånaderna antingen inte fanns någon skillnad eller en liten minskning av DOC-export. Detta påverkar sannolikt även de östra bassängerna där Stockholm tar sitt dricksvatten. Ökad DOC-export till Ekoln skulle troligen påverka Stockholms dricksvattenproduktion mer eftersom bassängerna har ett direkt vattenutbyte. GWLF-modellen som användes här visade potential i att simulera DOC-export till Mälaren i ett ändrat klimat. För att uppskatta framtida påverkan av DOC-export på dricksvattenproduktionen kring Mälaren behöver även processer som sker i sjön undersökas.
|
190 |
Bilirubin is a Metabolic Hormone that Improves Lipid MetabolismGordon, Darren Mikael January 2020 (has links)
No description available.
|
Page generated in 0.077 seconds