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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.
1

Aplica??o de Revestimentos Comest?vel em Caqui Mikado (Diospyros kaki) Minimamente Processado. Serop?dica: UFRRJ, 2009. / Evaluation of application of edible coatings in persimmon Mikado (Diospyros kaki) minimally processed and in nature in relation to cold storage. Serop?dica: UFRRJ, 2009

Neves Junior, Augusto C?sar Vieira 21 July 2009 (has links)
Made available in DSpace on 2016-04-28T14:58:38Z (GMT). No. of bitstreams: 1 Augusto CesarVieira Neves Junior.pdf: 2971994 bytes, checksum: e609bbbaf217d220df7b14eb6fba68bf (MD5) Previous issue date: 2009-07-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Minimally processed products are safe and ready to eat, in spite of adding value, has a short life. Edible coatings can be an important tool to ensure the quality and increase the shelf life of minimally processed products, including persimmon. The 'Mikado' variety Persimmon has astringency and need a specific astringency process to get a minimally processed product with quality. Therefore, the objective of this work was to develop and characterize the edible coatings for use in 'Mikado' minimally processed persimmon. It was necessary to determine the exposure time of the fruit to alcohol vapor until the decrease of astringency. It was performed the flowchart for the fresh-cut of persimmon evaluating the quality of the final product. Evaluations of thickness, gas permeability, mechanical properties of coatings applied were also performed. It was also verified the efficiency of use 70% alcohol (7.00 mL ?lcool.Kg-1 fruit) to reduce astringency. There were performed the following analysis: firmness, pH, total soluble solids (? Brix), total titratable acidity, total tannins and weight loss and sensory analysis during the process. These analyses were necessary to determine the time of exposure to the alcohol vapor to decrease the concentration of soluble tannic acids in fruit that it was not tasted by panelists and determine that concentration. It was evaluated persimmon storage with and without coatings. Three experiments were conducted during this work. In the first experiment, it was set up two coatings which were used in the second trial of minimally processed. It was evaluated four different types of coatings: cassava starch, sodium alginate, carboxymethyl cellulose (CMC) and bovine gelatin. In the first experiment (edible coating), it was set up two coatings which were used in the experiment of minimally processed. Four different types of coatings were evaluated: cassava starch, sodium alginate, carboxymethyl cellulose (CMC) and bovine gelatin. In the second experiment (astringency reduction) it was defined the time required to keep the fruits in alcohol atmosphere to reduce total soluble tannins tasted by panelists. The times tested were: 10 hours, 36 hours, 55 hours, 83 hours, 107 hours, 130 hours and 155 hours. It was defined a flowchart for persimmon minimally processed. The best coatings applied in minimally processed persimmon were the cassava starch and CMC. The firmness of the fruit remained until to 55 hours of exposure to alcohol vapor. Fruits were exposure to 83 hours or up caused loss firmness below that it is commercially tolerated. The astringency was not tasted by panelists from 55 hours exposure of alcohol vapor. The threshold detection of total soluble tannin in the pulp of fruit was 0.8161 ?g.100g-1. The tannins content decrease with the increasing exposure of fruit to alcohol vapor. The reduction of astringency with 70% alcohol vapor may not be the most indicated method due to high losses in this step (21.76%). The minimally processed fruits treated with CMC coating showed less dark spots in the pulp than the other treatments and all treatments were microbiological adequates. / Produtos minimamente processados s?o produtos seguros e de pronto consumo, que apesar de agregar valor, possui uma vida ?til mais reduzida. Os revestimentos comest?veis podem se constituir em importante ferramenta para garantir a qualidade e estender a vida ?til de produtos minimamente processados, entre eles, o caqui. O caqui Mikado por ser adstringente necessita de um processo adequado de destaniza??o para gerar um produto minimamente processado de qualidade. Diante disto, este trabalho teve como objetivos o desenvolvimento e caracteriza??o de revestimentos comest?veis para a utiliza??o em caqui Mikado minimamente processado, determina??o do tempo necess?rio de exposi??o ao vapor de ?lcool para que o fruto n?o apresente adstring?ncia e elabora??o de um fluxograma para o processamento m?nimo de caqui com avalia??o da qualidade do produto final. Para o desenvolvimento e caracteriza??o dos revestimentos foram realizadas avalia??es de espessura, permeabilidade gasosa, propriedades mec?nica e pr?via sensorial do caqui Mikado minimamente processado tratados com os revestimentos comest?veis. Definiram-se dois revestimentos [amido de mandioca e carboximetilcelulose (CMC)], a partir de quatro revestimentos (amido de mandioca, alginato de s?dio, CMC e gelatina bovina) para serem testados em caqui minimamente processado. Foi tamb?m avaliado o tempo de exposi??o ao vapor de ?lcool a 70% (7mL de ?lcool.Kg-1 de fruto), por meio de an?lises f?sicas, qu?micas e sensoriais. Tais analises foram necess?rias para determinar o tempo de exposi??o ao vapor de ?lcool que diminuiria a concentra??o de ?cido t?nico sol?vel nos frutos at? que este n?o fosse mais sensorialmente percept?vel, determinando esta concentra??o e verificando-se se o fruto tinha firmeza adequada ao minimamente processado. Desta forma, foi poss?vel determinar o limiar de detec??o dos taninos sol?veis (0,8161?g.100g-1) e o tempo de exposi??o ao vapor de ?lcool mais adequado para o processamento m?nimo, que provavelmente estava entre 55 e 83 horas, sendo que os tempos testados foram de: 10 horas; 36 horas; 55 horas; 83 horas; 107 horas; 130 horas; e 155 horas. A firmeza dos frutos se manteve adequada at? as 55 horas de exposi??o ao ?lcool, sendo que um tempo igual ou superior a 83 horas de exposi??o causou perda de firmeza a um n?vel abaixo do tolerado comercialmente. Por fim foi obtido um fluxograma da produ??o de caqui Mikado minimamente processado e avaliado o armazenamento com e sem revestimentos, sendo realizado para isto analises f?sicas, qu?micas, microbiol?gicas e sensoriais ao longo do per?odo de armazenamento de 10 dias. Para a realiza??o deste experimento (processamento m?nimo de caqui) utilizou-se revestimentos de amido de mandioca e de CMC, e o tempo de destaniza??o foi de 70 horas. Verificou-se que a destaniza??o neste tempo pode n?o ser a mais adequada devido ?s altas perdas verificadas nesta etapa (21,76% dos frutos n?o se mostraram adequados ao processamento m?nimo). Os frutos minimamente processados tratados com revestimento de CMC apresentaram-se com menos manchas na polpa que os demais tratamentos e todos os tratamentos mostraram-se adequados microbiologicamente.

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