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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

Influ?ncia da alta press?o hidrost?tica na sacarifica??o do mosto cervejeiro / The influence of high hydrostatic pressure in wort sacharification

Santos, L?gia Marcondes Rodrigues dos 28 November 2016 (has links)
Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-07-17T15:09:58Z No. of bitstreams: 1 2016 - L?gia Marcondes Rodrigues dos Santos.pdf: 1928089 bytes, checksum: 74cdeac055ec3629545f632b08dd75c4 (MD5) / Made available in DSpace on 2017-07-17T15:09:58Z (GMT). No. of bitstreams: 1 2016 - L?gia Marcondes Rodrigues dos Santos.pdf: 1928089 bytes, checksum: 74cdeac055ec3629545f632b08dd75c4 (MD5) Previous issue date: 2016-11-28 / Beer is the most consumed beverage in the world and Brazil is the third biggest producer just behind USA and China. It is an alcoholic beverage made from malted cereals, water, hops and yeast. To produce beer, water and malt are mixed and heated, what it is called the mashing step which aims to promote gelatinization and the starch hydrolyzation by the enzymes of the malt: ? and ? amylases. Since by using high hydrostatic pressure (HHP) it is possible to realize both processes (gelatinization and hydrolysis), mashing can use this technology without the need of heating and to raise productivity of the brewhouse. The aim of this study was to evaluate the use of HHP on starch hydrolysis and the sugar profile formed. For this, worts (water and malt solution ? ratio 4:1) were treated with HHP in 300, 400 or 500 MPa for 5, 10 and 15 minutes, and as control sample, the same solution was treated with heat (1st step: 52?C / 20 min; 2nd step: 72 ?C / 25 min; 3rd step: 78 ?C / 5 min). After, it was made the sugar profile by high performance liquid chromatography (HPLC), soluble solids content by density and microscopic analysis of gelatinized starch. As results, it was possible to verify a decrease on starch concentration (indication of hydrolysis) and a progressive swelling (indication of gelatinization) of the granules, especially at 500 MPa. The iodine test, which assesses starch presence, showed the same results of microscopy analysis and, on both qualitative assessments, the pressure level was of great influence and only on the iodine test, time seems to have had any influence since it was observed a decrease on starch content as time increased at 500 MPa. The sugar profile revealed five main sugars in all worts: glucose, sucrose, fructose, maltose and maltotriose. The maltose, maltotriose and fructose?s contents of the pressurized worts were similar to the heat treatment (500 MPa / 5 ? 15 min). Fructose and glucose exhibited and increase in most of the pressurizations. Sucrose and soluble solids contents of the pressurized samples were lower than the heated one. Among the pressure levels studied, there was a trend of increase on soluble solids, maltose, maltotriose and glucose?s content as the pressure was raised and generally, pressure influenced all sugar?s contents, except from sucrose. Time had a small effect on sugar?s content in some pressure levels. The variations observed to maltose, maltotriose and soluble solids were adjusted to mathematical models of fourth grade that exhibited a strong influence of pressure without dependence of the time effect. Additionally, the principal component analysis explained the variance with formation of three main clusters: heated wort, 500 MPa / 10 or 15 min wort and the other pressurized worts. The results showed that high hydrostatic pressure was able to promote desirable changes on mashing concerning gelatinization and hydrolysis with formation of desirable sugars, especially at 500 MPa. It suggests that it?s possible to produce wort by HHP providing productivity gains, once HHP takes less time (5 min against 80 min of usual heat process) and less energy consumption. / A cerveja ? a bebida alco?lica mais consumida no mundo, e o Brasil ? o terceiro maior produtor. No processo de produ??o convencional, a mostura ? a etapa que objetiva prioritariamente, promover gelatiniza??o e hidr?lise enzim?tica do amido pelas enzimas end?genas ? e ? amilases. A alta press?o hidrost?tica (APH) ? capaz de promover a gelatiniza??o de amido e ativa??o de enzimas e, desta maneira, a mostura demonstra ser uma etapa da fabrica??o de cerveja capaz de utilizar APH, no entanto h? poucos estudos na literatura sobre esta aplica??o. A adequa??o dessa tecnologia poder? propiciar esta etapa do processo sem necessidade de calor e com tempo reduzido, o que reverter? em aumento de produtividade e capacidade da ind?stria cervejeira. Desta maneira, o objetivo deste trabalho foi avaliar o efeito do processo da APH sobre a hidr?lise do amido para forma??o de a??cares durante a mostura. Para isso, mostos (solu??o contendo ?gua e malte ? 4:1) foram tratados por alta press?o hidrost?tica (APH) a 300, 400 ou 500 MPa por 5, 10 ou 15 minutos e, como controle do experimento, a mesma solu??o foi tratada termicamente (TT: 1? fase: 52?C / 20 min; 2? fase: 72 ?C / 25 min; 3? fase: 78 ?C / 5 min) . Posteriormente, procedeu-se an?lise do perfil de a??cares por cromatografia l?quida de alta efici?ncia (HPLC), o teor de s?lidos sol?veis por densitometria e an?lise microsc?pica da gelatiniza??o do amido. Como resultado, observou-se atrav?s da microscopia que houve diminui??o na concentra??o de amido (indicativo de hidr?lise) e um progressivo inchamento (indicativo de gelatiniza??o) dos gr?nulos com o aumento da press?o, principalmente a 500 MPa. O resultado do teste iodo (que avalia presen?a de amido) corroborou com o resultado da microscopia, indicando a diminui??o na concentra??o de amido a 500 MPa. O perfil de a??car revelou cinco sacar?deos principais: sacarose, frutose, glicose, maltose e maltotriose. As concentra??es de maltose, maltotriose e frutose dos mostos pressurizados foram similares ?s observadas no mosto TT quando nos n?veis mais intensos (500 MPa / 5, 10 e 15 min). Frutose e glicose exibiram aumento de concentra??o na maioria dos tratamentos avaliados. O teor de sacarose e de s?lidos sol?veis foram inferiores ao observado no mosto TT em todos os mostos tratados por APH. Entre os n?veis de APH avaliados, observou-se tend?ncia de aumento da concentra??o de s?lidos sol?veis, maltose, maltotriose e glicose com o aumento da intensidade de APH. De maneira geral, o efeito da press?o alterou o teor de todos os a??cares, exceto sacarose. J? o tempo exerceu discreto efeito na concentra??o dos a??cares quando pressurizados em alguns n?veis de press?o. O modelo matem?tico que melhor se ajustou aos dados experimentais dos teores de maltose, maltotriose e s?lidos sol?veis foi o de quarto grau, que exibiu forte influ?ncia do fator press?o sem depend?ncia do fator tempo, corroborando com as outras an?lises deste estudo. Adicionalmente, an?lises de componentes principais exibiu explica??o (CP1 + CP2) a 92 % de vari?ncia com forma??o de tr?s clusters principais: mosto TT, mostos 500 MPa / 10 ou 15 min e demais mostos tratados por APH. Os resultados demostraram que a APH foi capaz de promover as altera??es desej?veis no processo de mostura no que se refere aos efeitos de gelatiniza??o e hidr?lise com forma??o dos a??cares de interesse, principalmente nos n?veis mais intensos (500 MPa) de press?o. Esse resultado sugere que a produ??o de mosto por APH ? vi?vel tecnicamente, podendo vir a proporcionar ganho expressivo de produtividade, uma vez que a APH demanda menos tempo (5 min contra 80 min do tratamento t?rmico) e h? redu??o do consumo de energia.

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