Dissertations / Theses on the topic 'Beer fermentation'

One of the most important contributions to flavour compounds in beer is that associated with the activity of yeast. A kinetic model that quantitatively predicts the influence of changing process parameters on yeast metabolism and the production of flavour compounds would be invaluable. However a review of the literature has revealed that there is an absence of good quantitative data on which to build a model. The literature uses a wide variety of yeast strains and undefined fermentation media. There is also very little quantitative analysis of flavour formation and the models that have been published have little physiological relevance. The aim of the present study was to develop a kinetic model that would describe the production of the higher alcohols, isoamylalcohol and isobutanol, by the yeast N.C.Y.C 1681 within a brewery fermentation system. H.P.L.C., G.C. and enzyme assay analytical methods were developed that allowed the determination of concentrations of pertinent medium components during a fermentation. Amino acid concentrations were determined using Pico-tag (P.I.T.C.) pre-column derivatisation chemistry. Beer volatile components were analysed using G.C. head space analytical procedures. Yeast growth was studied in experimental defined media and in the complex wort medium. The vessels of the study were stirred tank fermenters, tall tubes and brewery cylindroconicals. Higher alcohol production is intimately linked with the yeast populations amino acid metabolism. Thus the influence of medium nitrogen content was investigated in relation to catabolic and anabolic production of higher alcohols.

The sugar composition of the wort and how these sugars are utilised by the yeast affects the organoleptic properties of the beer. To monitor the saccharides in the wort before inoculation and during fermentation is important in modern brewing industry. Reducing the duration of the brewing process is valuable and can be achieved by reducing the fermentation time by an increase in temperature. However, this must be done without changing the quality and characteristics of the end product, another incitement for proper monitoring of the wort. During fermentation, brewer´s yeast produces various by-products that affect the flavour in beer. The temperature has been reported to affect the metabolism of such compounds. In the present thesis work, monitoring with high performance chromatography of individual saccharides and ethanol was performed during a down-scaled industrial lager beer fermentation. Additionally, the effect of temperature on the fermentation rate was investigated. To determine if the metabolism of by-products was affected, a few higher alcohols and organic acids were monitored throughout the fermentation. Monitoring of degrading sugars and the production of ethanol with HPLC proved to be suitable. It is concluded that the fermentation rate is increased when the temperature is increased, however, further studies are needed to obtain more decisive results regarding secondary metabolite formation.

Orientador: Fernando Broetto
Banca: Willian Fernando Zambuzzi
Banca: Alcides Lopes Leão
Resumo: A cerveja é uma das bebidas mais consumidas no mundo. Seu consumo moderado é capaz de promover benefícios ao organismo pela presença de compostos bioativos, incluindo vitaminas do complexo B e minerais. O mercado de bebidas, sempre em busca de produtos exclusivos, favoreceu o surgimento do ramo de cervejas artesanais. Além disso, pela possibilidade de acesso às receitas, é concebível associar à bebida, certas características organolépticas e nutracêuticas de interesse funcional. Neste sentido, este trabalho teve como objetivo identificar possível associação dos efeitos funcionais da cerveja Pilsen ao potencial antioxidativo da polpa de maracujá. O delineamento experimental foi inteiramente casualizado, sendo o controle, o Tratamento 1 (T1) representado pela cerveja Pilsen, produzida artesanalmente. Nos demais tratamentos, as cervejas foram suplementadas com polpa de maracujá em três concentrações, durante o processo de refermentação (priming). Para o tratamento 2 (T2), a cerveja foi suplementada com polpa integral de maracujá (120 mL); Para os tratamentos T3 e T4, a suplementação com polpa foi da ordem de 50 e 25 % da polpa diluída, respectivamente. Todos os tratamentos foram repetidos três vezes, em brassagens independentes. Os processos de mosturação e fermentação da cerveja seguiram os procedimentos padrões de brassagem e maturação típicas de cervejas lager, com temperatura controlada entre 11 e 13 °C. Após a produção das cervejas, realizou-se análise sensorial, por meio d... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Beer is one of the most consumed alcoholic drinks in the world and the moderate intake is able to promote benefits to the organism by the presence of bioactive compounds. The beverage market looks for exclusive products and it favors artisanal beer sector. It is possible associate some organoleptic and nutraceutical characteristics of functional interest at drink. The objective of this study was to identify a possible association of the functional effects of Pilsen beer with the antioxidant potential of passion fruit. The experimental design was random; the control (T1) treatment was Pilsen beer without addition of passion fruit pulp. The others treatments (T2, T3 e T4) containing passion fruit pulp added in 3 concentrations (100% of the whole pulp corresponding to 120ml, 50% in proportion 1 pulp: 1 water, and 25% in proportion 1 pulp: 3 water), with 3 replicates. It was used standard brewing procedures of Pilsen beer. Sensory analysis was accounted by means of acceptance test and physicochemical analysis. The supplemented with passion fruit pulp beers had higher values of biochemical parameters. The treatment T2 had the lowest sugar content and higher contents of phenolic compounds and antioxidant capacity. The supplementation of beer with different percentage of passion fruit pulp did not interfere with the acceptability of the drink by the tasters when compared to the traditional Pilsen beer. However, male evaluators preferred treatment T2 for taste and smell attributes. T... (Complete abstract click electronic access below)
Mestre

Through a full factorial design experiment, the effects of time between worts, wort aeration and yeast dosage in production of a pale lager beer were examined in the beer process at Spendrups Bryggeri AB. The aim was to learn how different parameters may affect the yeast fermentation performance during beer production. Response variables used were the concentrations of ethyl acetate and isoamyl acetate, free amino nitrogen (FAN) degradation and change in extract. A statistical analysis showed that the concentration of ethyl acetate is dependent on yeast dosage and the interaction between time between worts and aeration while the isoamyl acetate concentration is dependent on yeast dosage and time between worts. No parameters are statistically significant for FAN degradation while the change in extract is dependent on the yeast dosage. Due to botched runs, mostly because of aeration problems, it was not possible to verify theoretical parameter values and responses. Since the aeration was not properly performed, the management of the aeration control should be further investigated. Ester analysis and analysis of FAN were performed as worts entered and exited horizontal fermentation tanks. An additional analysis of ester content was also performed as the early stage beer was transferred into lagering tanks. Cell viability as well as extract, pH and tank temperature was measured daily to verify the state of fermentation. Statistical calculations showed that when using NucleoCounter YC-100, there is no significant difference between analysis made of samples homogenized by a magnetic stirrer and samples shaken by hand.

Mestrado Vinifera Euromaster - Instituto Superior de Agronomia - UL
In the last few decades both beer and wine world started to innovate themselves, aiming to produce higher quality beverages, this brought life to a virtuous circle in which the consumers are becoming more informed and the producers invest money for the development of high quality and innovative beverages. The main objective of the work was to produce a fermented drink that conjugates beer and wine world. In order to do achieve this goal, we developed, optimized and characterized a fermented drink produced from grape must and beer wort using non-conventional yeast strains. The beer wort is produced with Braumeister (machinery that is able to maintain the temperature stable, thus having a high quality product) from Pilsner malt and blended with equal amount of Grape juice. The fermentation of the mix was performed using two strains of Torulaspora delbrueckii, one isolated from a beer media and one from a wine media, a strain of Brettanomyces bruxellensis and three different strains of S. cerevisiae¸ one used to ferment wine (ISA1000) and the two beer yeast with very opposite characteristics, US-05 is used to ferment ales style and it should be very neutral while WB-06 is used to ferment wheat beer and it gives an estery aroma to the beverage. Fermentation was monitored analysing the difference in the refraction index on the Brix° scale and composition analysed daily by HPLC. In order to choose the most suitable beverage, each drink was analysed by a trained panel aiming to describe the analytic profile of the beverage, and by a non-trained panel aiming to evaluate the degree of preference of these new beverages. Based on a compromise between technological issues and consumers preferences, the best beverage was the one obtained with S.cerevisiae WB-06.

Pendant la fermentation de la bière, du diacétyle apparait. Le diacétyle est responsable d'un défaut de gout ; il doit être éliminé par les levures, ce qui prend du temps. L’acétolactate décarboxylase est une enzyme qui permet d'éviter la formation de diacétyle pendant la fermentation de la bière. L’utilisation d'acétolactate décarboxylase pendant la fermentation de la bière permet d'accélérer le procédé. L’encapsulation de l'acétolactate décarboxylase a été envisagée dans le but de la retirer du mout et de la réutiliser. Ainsi les coûts seront réduits et la bière finale sera exempte de résidu. La méthode analytique de mesure d'activité acétolactate décarboxylasique a été optimisée car les procédures citées dans la littérature donnaient des résultats peu précis. L’immobilisation de l'enzyme par inclusion en billes de gel s'est révélée inadéquate car l'enzyme est de petite taille et fuit dans le milieu extérieur. L’emprisonnement dans des capsules de complexes polyélectrolytes montre de bons rendements d'encapsulation. Les capsules fabriquées font 800 micromètre de diamètre et le rendement d'encapsulation est de 80% (activité des capsules rapportée à l'activité de l'enzyme libre). Les enzymes libres et encapsulées présentent des profils d'activité semblables au cours du temps. La fermentation de la bière a été modélisée. L’utilisation d'acétolactate décarboxylase a été introduite dans le modèle. Elle permet de réduire la durée de fabrication de 43%. L’utilisation d'acétolactate décarboxylase encapsulée permet d'obtenir les mêmes performances. Ceci prouve que les transferts sont suffisants et que notre méthode d'encapsulation est efficace.

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A cerveja é uma das bebidas mais consumidas no mundo. Seu consumo moderado é capaz de promover benefícios ao organismo pela presença de compostos bioativos, incluindo vitaminas do complexo B e minerais. O mercado de bebidas, sempre em busca de produtos exclusivos, favoreceu o surgimento do ramo de cervejas artesanais. Além disso, pela possibilidade de acesso às receitas, é concebível associar à bebida, certas características organolépticas e nutracêuticas de interesse funcional. Neste sentido, este trabalho teve como objetivo identificar possível associação dos efeitos funcionais da cerveja Pilsen ao potencial antioxidativo da polpa de maracujá. O delineamento experimental foi inteiramente casualizado, sendo o controle, o Tratamento 1 (T1) representado pela cerveja Pilsen, produzida artesanalmente. Nos demais tratamentos, as cervejas foram suplementadas com polpa de maracujá em três concentrações, durante o processo de refermentação (priming). Para o tratamento 2 (T2), a cerveja foi suplementada com polpa integral de maracujá (120 mL); Para os tratamentos T3 e T4, a suplementação com polpa foi da ordem de 50 e 25 % da polpa diluída, respectivamente. Todos os tratamentos foram repetidos três vezes, em brassagens independentes. Os processos de mosturação e fermentação da cerveja seguiram os procedimentos padrões de brassagem e maturação típicas de cervejas lager, com temperatura controlada entre 11 e 13 °C. Após a produção das cervejas, realizou-se análise sensorial, por meio de teste de aceitação e demais análises físico-químicas. A adição de polpa de maracujá como adjunto no processamento da cerveja mostrou-se alternativa viável demonstrada pelos resultados satisfatórios na avaliação sensorial, além de apresentar características físico-químicas de cerveja artesanal frutada. O tratamento T2 apresentou o menor teor de açúcar e maiores teores de compostos fenólicos e capacidade antioxidante. A suplementação da cerveja com diferentes porcentagem de polpa de maracujá não interferiu na aceitabilidade da bebida pelos provadores quando comparada com a cerveja Pilsen tradicional. Entretanto, os avaliadores do sexo masculino tiveram preferência pelo tratamento T2 para atributos de sabor e odor.
Beer is one of the most consumed alcoholic drinks in the world and the moderate intake is able to promote benefits to the organism by the presence of bioactive compounds. The beverage market looks for exclusive products and it favors artisanal beer sector. It is possible associate some organoleptic and nutraceutical characteristics of functional interest at drink. The objective of this study was to identify a possible association of the functional effects of Pilsen beer with the antioxidant potential of passion fruit. The experimental design was random; the control (T1) treatment was Pilsen beer without addition of passion fruit pulp. The others treatments (T2, T3 e T4) containing passion fruit pulp added in 3 concentrations (100% of the whole pulp corresponding to 120ml, 50% in proportion 1 pulp: 1 water, and 25% in proportion 1 pulp: 3 water), with 3 replicates. It was used standard brewing procedures of Pilsen beer. Sensory analysis was accounted by means of acceptance test and physicochemical analysis. The supplemented with passion fruit pulp beers had higher values of biochemical parameters. The treatment T2 had the lowest sugar content and higher contents of phenolic compounds and antioxidant capacity. The supplementation of beer with different percentage of passion fruit pulp did not interfere with the acceptability of the drink by the tasters when compared to the traditional Pilsen beer. However, male evaluators preferred treatment T2 for taste and smell attributes. The addition of passion fruit pulp proved to be a viable alternative demonstrated by the satisfactory results in the sensorial evaluation.

This thesis studies the development of the “macro” and “craft” sectors of the brewing industry. After a comprehensive understanding of the history of beer, the focus segues into the economic development of the industry – including macro and microbrewery concentration, strategy analysis, and the recent emergence of craft breweries. Finally, two data sets are analyzed. The first examines overall industry trends against factors of horizontal differentiation, while the second observes how certain characteristics of an individual beer drinker indicate the degree to which their taste in / preference for beer has changed over the last five years. Results show that with the diminishment of homogeneity (via quality of ingredients and cultural shifts), craft breweries emerged. Furthermore, traits such as the quality of a beer drunk and the number of beers drunk a week are strong indicators that an individual beer drinker’s taste for beer has changed in the last five years. These findings, supported by earlier industry observations, suggest that craft breweries will continue to acquire a larger share of the American brewing industry.

Ce travail a pour objectif de concevoir un procédé de fermentation en lit fixe par levures immobilisées destiné à la fermentation partielle d'un mout brassicole. La première partie de ce travail a consisté à évaluer la capacité massique de rétention cellulaire d'un nombre important de matériaux différents. Le protocole mis en œuvre permet d'apprécier l'influence des matériaux sur le ph des milieux de fermentation, leur comportement à l'attrition et d'estimer la solidité de la liaison cellule-support. L'étude porosimétrique de ces matériaux permet de les classer en trois catégories : matériaux macroporeux, microporeux et de porosité intermédiaire et d'estimer la surface disponible pour l'immobilisation cellulaire. Ces études permettent une première sélection de cinq matériaux. L'étude comparative d'une fermentation de mout brassicole, en laboratoire, sur des lits fixes de ces matériaux, permet d'estimer leur capacité massique de rétention cellulaire, de vérifier la stabilité de la fermentation et de mesurer l'influence des matériaux sur la flaveur du produit fermenté. Ces études conduisent au choix d'un support d'immobilisation cellulaire. La seconde partie de ce travail concerne l'élaboration de protocoles de mise en œuvre de ce support, aisément transposables a l'échelle industrielle : stérilisation du matériau, colonisation cellulaire du matériau, traitement des pollutions microbiennes éventuelles. Le fermenteur a un comportement hydrodynamique complexe, qui peut être représenté par une combinaison de réacteurs parfaitement agités, de zones d'échanges, de zones mortes et de réacteurs pistons. La troisième partie de ce travail a concerné l'étude de la fermentation partielle d'un mout brassicole, au sens d'une faible production d'éthanol, a l'échelle pilote. Elle s'est intéressée a l'existence d'un gradient vertical stable de concentration en levures immobilisées, a la consommation de tous les sucres fermentescibles, au rendement de production d'éthanol et a celui de production de biomasse en suspension qui varient en fonction de la hauteur de lit, a la stabilité opérationnelle du fermenteur pilote, a la production de précurseurs de dicétones et a la consommation de composes carbonyles.

Diacetyl (2,3-butanedione) is an important flavour active, oxidative compound that has significant impact on cellular health as well as financial impact in industrial fermentations. The presence of diacetyl in certain fermented beverages, such as beer, results in an unpleasant butterscotch-like flavour and its concentration needs to be reduced by yeast to below the taste threshold prior to filtration and packaging. This results in significant process inefficiency. Furthermore, diacetyl negatively impacts cellular health and has been associated with neurodegenerative diseases and general cell aging amongst others. The reduction of this compound is therefore essential for cellular health.
Several yeast cell enzymatic mechanisms responsible for diacetyl reduction were identified and characterised, including Old Yellow Enzyme (OYE) isoforms and D-Arabinose Dehydrogenase (ARA1). OYE isoforms displayed different micromolar affinities and catalytic turnover rates for diacetyl and catalysed diacetyl reduction in a biphasic manner. ARA1 catalysed diacetyl reduction in a monophasic manner with a millimolar Michaelis constant.
Knowledge gained in these studies was applied in investigations of diacetyl production and reduction in industrial brewing operations and the enzymatic systems further exploited for the development of a novel enzyme based assay to determine diacetyl concentrations in beer samples. Concentrations as low as 0.2 muM were detectable with high repeatability.

Antalet mikrobryggerier runt om i Sverige har de senaste åren ökat markant. Vanligast är att dessa producerar öl som ale och stout trots att vi svenskar, om man ser till systembolagets statistik, fortfarande främst dricker lager. En anledning till få av de mindre mikrobryggerierna brygger lageröl är att bryggprocessen är mer avancerad för att brygga lager. För att brygga lager krävs, utöver den vanliga bryggutrustningen, också ett sätt att kyla ölet på först till 10°C och sedan till 0°C under en längre period. Den utrustning som används av de flesta större mikrobryggerierna är för dyr för de mindre mikrobryggerierna och bryggning av lageröl uteblir därför ofta. Ett exempel på ett mindre mikrobryggeri som har detta problem är Brewing Költur och detta arbete har haft som avsikt att lösa kylproblemet för dem. Arbetet gick ut på att ta fram ett alternativt sätt, dels att kyla en sats öl på, 300 liter, dels att hålla ölet kallt utan större fluktuationer under en längre tid. En viktig del i lösningen är att investeringskostnaden för kylanläggningen skulle vara avsevärt lägre än de alternativ som finns på marknaden idag. Projektet hade dock inte som avsikt att lösa övriga problem som finns med bryggning av lager. Resultatet blev en Bag-in-Box: en frysbox i vilken en engångspåse placerades. En luftspalt skapades mellan påsen och frysens innerkanter för att sakta ner värmeöverföringen och på så vid undvika att kyla ned jästen för snabbt vilket (annars) kan få allvarliga konsekvenser på ölet. En prototyp av produkten kylanläggningen byggdes ihop på vilken tester utfördes. Testerna visade att produkten utan problem kunde hålla stabila temperaturer under längre perioder, framförallt vid de lägre temperaturerna. Vid nedkylning från 10°C samt vid hållning av denna temperatur krävdes viss komplettering med manuell omrörning för att undvika stora temperaturgradienter i påsen. Investeringskostnaden för produkten är mycket låg medan de rörliga kostnaderna är relativt höga på grund av engångspåsen då det går åt en eller två sådana per sats bryggd öl. På grund av produktens låga investeringskostnad, enkla montering samt relativt goda förmåga att hålla temperaturer konstanta anses produkten ha potential att kunna ha stor betydelse för mindre mikrobryggerier i framtiden.
There has been a large increase of microbreweries in Sweden in the past few years, most of which produce great beers such as ales and stouts. This is however a bit strange since most Swedes seem to prefer to drink lager; at least if you study the statistics of the Swedish alcohol monopoly’s top hundred most drunken beers last year. There might be several reasons for microbreweries not brewing lagers but one reason is the equipment needed for lager brewing. Apart from the regular brewing equipment needed for brewing ales, a cooling system is needed in lager brewing in order to reach the ideal temperatures for fermentation, 10°°C, and lagering. Lagering is a process where beer is stored for weeks or months in a cold place, typically around 0°C.  The cooling systems on the market are expensive and small start-up microbreweries do not have the funds to purchase these. One example of such a microbrewery is Brewing Költur, and this study aims to solve the cooling problem for them. The goal was to design a cheaper alternative for cooling a 300-litre batch of beer but without severe changes in quality. The product needs to be able to hold stable temperatures and also lower the temperatures from 10°°C to 0°°C, both without major fluctuations in temperature within the vessel. The project did not aim at solving other lager brewing related problems. The result was a Bag-in-Box: a chest freezer in which a disposable plastic bag, big enough to fit 300 litres of beer, was placed. An air gap was created in between the inside walls of the freezer and the bag to keep the sudden cold walls from damaging the yeast by cooling it to quickly. A prototype was put together in order to test the most important features of the product. The tests showed that the product could keep stable temperatures very well in the lower temperature intervals, while it needed manual stirring in the higher regions to avoid temperature gradients, especially when the temperature was lowered. The cost of the product is overall very low. The investment cost is very low, however since the disposable bags are somewhat costly the variable cost is fairly high, yet still significantly cheaper than the alternatives on the market. It is believed that the product could be used by many smaller microbreweries in the future due to the low investment cost, its ability to keep the temperatures relatively stable and also because it is easy to assemble.

O Brasil ocupa o 3º lugar entre os maiores produtores mundiais de cerveja e o mercado consumidor vem aumentando progressivamente. Tendo em vista que o consumidor brasileiro está em busca de novos sabores e aromas para a cerveja, uma alternativa para a redução de custos explorando tais características reside no uso de adjuntos não convencionais que possam agregar valor à bebida, principalmente na obtenção de boas características sensoriais. Ainda, visando à sustentabilidade, estes adjuntos podem ser coprodutos do processamento de alimentos. O permeado concentrado de leite, um coproduto dos laticínios, é obtido através da ultrafiltração do leite, sendo composto por água, lactose e sais. Neste trabalho foi desenvolvido um processo para a produção de uma cerveja de alta fermentação (ale), utilizando o permeado concentrado de leite como adjunto de fabricação. Foram obtidas cervejas ale com a proporção malte/permeado de 55/45 e 90/10, utilizando para isso, permeado hidrolisado pela enzima ?-galactosidase e permeado não hidrolisado. A caracterização do permeado revelou que este possui três vezes mais lactose que o soro de queijo. A melhor condição de hidrólise enzimática da lactose presente no permeado foi obtida empregando-se 2,0 mL/L de ?-galactosidase em 90 minutos, alcançando 92,5% de hidrólise. Nas cervejas com permeado hidrolisado observou-se que a presença de galactose aumentou o tempo de fermentação para 168h e a atenuação real de fermentação dos mostos também foi maior em comparação as cervejas com permeado não hidrolisado, nos quais a lactose não foi fermentada. As cervejas 90/10 com permeado hidrolisado e não hidrolisado receberam as maiores notas na análise sensorial, tendo boa aceitação entre os provadores. Como não houve diferença estatística entre as duas, foi possível reduzir custo e tempo na produção da cerveja 90/10 em escala piloto (120L) por não ser necessário o processo de hidrólise enzimática. O permeado concentrado de leite mostrou-se um excelente adjunto na produção de cervejas ale e quando empregado em baixa concentração, produziu cervejas com boa aceitação sensorial.
Brazil ranks 3rd among the largest world producers of beer and the consumer market is increasing steadily. Considering that the Brazilian consumer is looking for new flavors and aromas to the beer, a possible solution for costs reduction exploring such characteristics is using unconventional adjuncts that can increase quality of the beverage, especially in getting good sensory characteristics. In addition, aiming at sustainability, such adjuncts can be coproducts of processing foods. The concentrated milk permeate, which is a dairy factory coproduct, is obtained by milk ultrafiltration, comprising water, lactose and salts. In this work it was development a process for the production of an ale beer using concentrated milk permeate as adjunct. Ale beers were obtained from the proportion malt/permeate 55/45 and 90/10, using both permeate hydrolyzed by ? - galactosidase enzyme and permeate not hydrolyzed. The characterization of the permeate revealed that it has three times more lactose than cheese whey. The best condition of enzymatic hydrolysis of lactose present in the permeate was obtained using 2.0 mL/L of ?-galactosidase within 90 minutes, reaching 92.5 % of hydrolysis. It was observed that the presence of galactose in beers wort with hydrolysed permeate increased fermentation time to 168 h and the real attenuation of fermentation were also higher compared with non-hydrolysed permeate beers, in which lactose is not fermented. The beers 90/10 with hydrolyzed and non-hydrolyzed permeate received the highest scores in sensory analysis, meaning a good acceptance among the tasters. Once there was no statistical difference between them, it was possible to reduce costs and time in beer 90/10 production on a pilot scale (120L) for not being necessary the enzymatic hydrolysis process. The concentrated milk permeate has proved to be an excellent adjunct in the production of ale beers. It produced ale beers with good sensory acceptance when used in low concentration.

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Among the main challenges in the beer industrial production is the market supply at the lowest cost and high quality, in order to ensure the expectations of customers and. consumers The beer fermentation stage represents approximately 70% of the whole time necessary to its production, having a obligatoriness of strict process controls to avoid becoming bottleneck in beer production. This stage is responsible for the formation of a series of subproducts, which are responsible for the composition of aroma/bouquet existing in beer and some of these subproducts, if produced in larger quantities, they will confer unpleasant taste and odor to the final product. Among the subproducts formed during the fermentation stage, total vicinal diketones is the main component, since it is limiting for product transfusion to the subsequent steps, besides having a low perception threshold by the consumer and giving undesirable taste and odor. Due to the instability of main raw materials quality and also process controls during fermentation, the development of alternative forms of beer production without impacting on total fermentation time and final product quality is a great challenge to breweries. In this work, a prior acidification of the pasty yeast was carried out, utilizing for that phosphoric acid, food grade, reducing yeast pH of about 5.30 to 2.20 and altering its characteristic from flocculent to pulverulent during beer fermentation. An increase of six times was observed in amount of yeast cells in suspension in the second fermentation stage regarding to fermentations by yeast with no prior acidification. With alteration on two input variables, temperature curve and cell multiplication, which goal was to minimize the maximum values for diketones detected in the fermenter tank, a reduction was obtained from peak of formed diacetyl and consequently contributed to reduction in fermentation time and total process time. Several experiments were performed with those process changes in order to verify the influence on the total fermentation time and total vicinal diketones concentration at the end of fermentation. This experiment reached as the best production result a total fermentation time of 151 hours and total vicinal diketone concentration of 0.08 ppm. The mass of yeast in suspension in the second phase of fermentation increased from 2.45 x 106 to 16.38 x 106 cells/mL of yeast, which fact is key to a greater efficiency in reducing total vicinal diketones existing in the medium, confirming that the prior yeast acidification, as well as the control of temperature and yeast cell multiplication in fermentative process enhances the performance of diketones reduction and consequently reduce the total fermentation time with diketones concentration below the expected value (Max: 0.10 ppm)
Dentre os principais desafios que se apresentam no mercado industrial de produ??o de cerveja nos dias atuais, podemos citar o abastecimento do mercado com o menor custo poss?vel e com qualidade, visando garantir as expectativas dos clientes e consumidores. A etapa de fermenta??o da cerveja representa aproximadamente 70% de todo o tempo necess?rio para sua produ??o, tendo uma obrigatoriedade de rigorosos controles de processo, para n?o se tornar gargalo da produ??o de cerveja. Essa etapa ? respons?vel pela forma??o de uma s?rie de subprodutos, os quais, ao mesmo tempo em que s?o determinantes da composi??o do buqu? de aromas existentes na cerveja, se produzidos em maior quantidade, podem passar para o produto final sabor e odor desagrad?veis. Dentre esses subprodutos, as dicetonas vicinais totais constituem o principal componente, uma vez que, al?m de serem limitantes quanto ? trasfega do produto para as etapas subsequentes, possuem um baixo limiar de percep??o pelo consumidor e passam sabor e odor desagrad?veis. Devido ? instabilidade da qualidade das mat?rias primas principais e dos controles de processo durante a fermenta??o, o desenvolvimento de formas alternativas de produ??o de cerveja com impactos positivos no tempo total de fermenta??o e na qualidade do produto final, ? um grande desafio dentro das cervejarias. Neste trabalho, foi realizada uma acidifica??o pr?via do fermento pastoso, utilizando-se, para isso, ?cido fosf?rico, grau aliment?cio e reduzindo-se o pH do fermento de aproximadamente 5,30 para 2,20. Al?m disso, com intuito de minimizar os valores m?ximos encontrados de dicetonas totais no tanque fermentador, foram alteradas duas vari?veis de entrada: a curva de temperatura e a multiplica??o celular. Obtiveram-se, como melhores resultados, o tempo total de fermenta??o de 151 horas e concentra??o de dicetonas totais de 0,08 ppm. Desta forma, foi confirmado que a acidifica??o pr?via do fermento, bem como o controle de temperatura e multiplica??o celular no processo fermentativo, aumentam a performance do processo atrav?s da redu??o das dicetonas totais e conseq?entemente, a redu??o do tempo total de fermenta??o com concentra??o de dicetonas abaixo do valor esperado (Max: 0,10 ppm)

This master thesis continues the master thesis Výroba vodíku z biomasy. In that work were performed first experiments of hydrogen production from beer less by dark fermentation. Further experiments will continue based on previous experiments. For the energy balance were used results from [1] and data obtained from literature searches, because the results of the experiments were not entirely satisfactory. Energy balance was calculated for a laboratory fermenter to evaluate the efficiency of energy obtainable from the hydrogen produced by fermentation in a dark laboratory conditions. It was compared the yield given in [1] and yield derived from a literature review. The conclusion presents recommendations for further research.

Nos últimos anos, duas tendências tem se destacado no universo cervejeiro: a obtenção de cervejas a partir de mostos concentrados e a elaboração de cervejas utilizando adjuntos especiais, os quais podem aromatizar ou não as mesmas. Visando um aumento da produtividade juntamente com uma menor necessidade de investimentos na capacidade produtiva, algumas cervejarias vêm optando pelo aumento do extrato inicial de fermentação para valores superiores aos tradicionais (10-15 0P). A elaboração de cervejas utilizando adjuntos especiais vem se tornando uma solução de barateamento na obtenção de cerveja devido à substituição de parte do malte, acrescentando ainda, atributos sensoriais característicos nos produtos obtidos. A banana constitui-se em matéria-prima bastante favorável à fermentação alcoólica por ser rica em carboidratos, minerais e apresentar baixa acidez. O principal objetivo desta pesquisa foi utilizar a banana como um adjunto do malte e como um aromatizante natural e sutil das cervejas obtidas. A quantificação dos carboidratos presentes na banana prata em diferentes graus de maturação revelou que a condição \"muito-madura\", apresentou o mais alto teor de carboidratos totais solúveis (15,65 %) e o mais baixo teor de amido (0,48 %). Após a etapa quantificação dos carboidratos fez-se um estudo da extração aquosa a quente dos sólidos solúveis da banana com a metodologia de superfície de resposta a partir de um planejamento fatorial 22 onde se obteve um modelo matemático empírico quadrático (Y = 5.58 + 1.25 X1 - 0.26 X2 - 0.37 X22). Os valores que otimizaram esta extração (Y) foram 38,5 g de purê de banana (X1) e tempo de extração de 39,7 minutos. Utilizando um planejamento fatorial 22 fez-se um estudo da fermentação do mosto com adjunto de banana, na planta piloto da microcervejaria da EEL - USP em diferentes concentrações e temperaturas. Observou-se que a 12 0P e a 15 0C obteve-se uma Qp de 0,58 g/L.h em 72 h de fermentação e apenas 6,07 % do açúcar metabolizado pela levedura cervejeira foi desviado para a geração de produtos secundários, garantindo um Yp/s real de 0,48 g/g. Dentro destas condições de estudo investigou-se o comportamento cinético da levedura cervejeira Saccharomyces cerevisiae 308 de baixa fermentação (tipo lager) nestes mostos com banana, de densidade tradicional. Pôde-se observar que o máximo valor de ?x (0,114 h-1) foi alcançado com a fermentação a 12 0P e 15 0C. O valores máximos de ?s e ?p (1,128 e 0,585 g/g.h, respectivamente) foram conseguidos com a fermentação a 15 0P e 15 0C. Em seguida, fez-se um estudo com o propósito de aumentar a produtividade volumétrica de etanol em mostos com banana de alta densidade. Para isto, realizou-se fermentações com a adição de diferentes nutrientes, em mini-bioreatores cilindrocônicos de 0,9 L da Uminho - Portugal. Verificou-se que apenas a adição de MgSO4 foi significativa estatisticamente para o aumento da Qp. Observou-se também que o melhor valor de Qp (0,68 g.L/h) foi alcançado em 64 h de fermentação após suplementação com 420 mg/L de MgSO4. Em seguida, fez-se a caracterização físicoquímica da cerveja obtida com a reprodução do experimento otimizado em mini-bioreator cilindrocônico de 0,9 L da Uminho - Portugal no fermentador de 180 L da EEL - USP, verificando-se que a cerveja com banana de 4,8 % v/v apresentou uma elevada concentração de potássio (600,68 mg/L) e de acetato de isoamila (1,20 mg/L). Das cervejas otimizadas elaboradas na planta piloto da USP, fez-se uma avaliação sensorial comparando-as com cervejas do mercado brasileiro. Observou-se que em relação aos testes de preferência, as cervejas com banana foram estatisticamente preferidas em relação às amostras do mercado. Já os testes de aceitação demonstraram que não houve diferença significativa (p >= 0,05) quanto ao grau de aceitação entre os produtos correspondentes às amostras experimentais otimizadas e as amostras do mercado. Ou seja, as amostras de cerveja com banana foram tão aceitas pelo consumidor quanto às amostras de cerveja do mercado. Por fim foi realizado um estudo econômico preliminar, dentro de uma estimativa de produção de 875 L/mês de cerveja com banana em microcervejaria. Verificou-se que o custo inicial do processo foi 204,76 % superior a de uma cerveja comercial. Todavia, o custo direto variável de produção desta cerveja foi de R$ 0,94/L contra R$ 1,10/L de uma cerveja puro malte produzida nas mesmas condições de processo.
In the past years, two tendencies have been revealed in the universe of brewing: beer production using concentrated wort and its elaboration using special adjunct, which might supply or not a special flavour to the beer. Aiming to increase the process productivity along with decreasing the necessity of further production investments, some breweries have adapted to increase the initial fermentation extract concentration to values superior to the traditional ones (10-15 oP). The elaboration of beer using special adjunct is considered a solution to turn cheap beer production by not only by substituting part of the malt but also in adding characteristic sensorial attributes in the obtained products. Banana is constituted of raw materials suitable for alcoholic fermentation for being rich in carbohydrates and minerals and present law acidity. The principal objective of this research is to utilize the banana as an adjunct for malt and also as a natural and a tenuous flavouring agent for the obtained beer. The quantification of the carbohydrates present in the banana prata in different maturation grade, has revealed that the condition of \"very mature\" represented the highest content in total soluble carbohydrates (15.65%) and the lowest content in starch (0.48%). After the quantification stage of the carbohydrates, a study was done on the hot aqueous extraction of the soluble solids found in the banana using the response-surface method obtained by a complete 22 factorial design. The obtained mathematical empirical quadratic model was (Y = 5.58 + 1.25 X1 - 0.26 X2 - 0.37 X22). The values of the optimized extraction (Y) was 38.5 g of banana pulp (X1) and an extraction time of 39.7 minutes. It was done a study on the fermentation wort with banana adjunct using a factorial design 22, in the micro-brewery pilot plant located in the EEL - USP, at different concentrations and process temperatures. It was observed that at 12 0P and at 15 0C, it was obtained a Qp of 0.58 g/L.h in 72 h of fermentation and only 6.07 % of the sugar metabolized by the alcoholic-yeast was deviated for the production of secondary products, which guaranteed a real Yp/s of 0.48 g/g. Using these conditions in study, it was investigated the kinetic behavior of the alcoholic-yeast Saccharomyces cerevisiae 308 of law fermentation (lager type) in these wort using banana, of conventional gravity. It can be observed that the maximum value of ?x (0.114 h-1) was achieved with fermentation at 12 0P and 150C. The maximum values of ?s and ?p (1.128 e 0.585 g/g.h, respectively) was obtained at fermentation of 15 0P and 15 0C. It was also done studies with the objective of increasing the volumetric productivity of ethanol in worts with banana at high gravity. For this reason, it was done several fermentations with the addition of different nutrients, in mini-bioreactors cylindrical-conical de 0.9 L from UMinho-Portugal. It was verified that the addition of MgSO4 was statistically significant for the increase in Qp. It was also verified that the best value of Qp (0.68 g.L/h) was achieved in 64 h of fermentation after being supplemented with 420 mg/L of MgSO4. It was also done a physical-chemical characterization of the beer obtained from the reproduction of the optimized experiment obtained using the cylindrical-conical bioreactor de 0.9 L from UMinho- Portugal in the bioreactor of 180 L of working volume located in the EEL - USP, verifying that the beer with banana (4.8 % v/v) have presented a high concentrations of potassium (600.68 mg/L) and isomile acetate (1.20 mg/L). It was done a sensorial evaluation of the elaborated beer in the pilot-plant in the USP, comparing it with the other beers found in the Brazilian market. It was observed that in relation to the preference test, beers with banana were statistically preferred in relation to the other samples. Acceptance tests demonstrated that there has been no significant difference (p>= 0.05) in relation to the grade of acceptance between the products corresponding to the samples taken from the optimized experiments and the samples taken from the market. In other words, the samples with banana were acceptable by the consumer as much as the samples taken from common beers found in the market. Finally, it was done a preliminary economical evaluation of the process, considering as production capacity the value of 875 L/month of beer with banana. It was calculated the initial cost of the process was of 204.76% superior than the commercial draft beer. On the other hand, the direct cost of production of this draft beer was of R$ 0.94/L against R$ 1.10/L of draft beer made from pure malt using the same process conditions.

O presente trabalho apresenta a análise térmica do fenômeno de fermentação de cerveja com o objetivo de quantificar a energia liberada durante o processo e avaliar o comportamento do campo de temperaturas do fermentando. É adotada uma metodologia que reúne abordagens teóricas e experimentais, aplicadas a um processo completo de fermentação. O calor dissipado durante a fermentação é calculado por equações presentes na literatura, tendo como entrada a taxa de conversão de glicose e produção de CO2. Essas taxas são calculadas pelas concentrações de glicose medidas de amostras retiradas durante ensaios planejados. A dissipação é usada como entrada em dois modelos térmicos para o cálculo do campo de temperaturas do fermentando. As temperaturas calculadas são superiores àquelas monitoradas experimentalmente, com diferenças de até 78%. Esse comportamento embasa a proposta de uma equação de ajuste do calor liberado durante a fermentação. A equação proposta indica que é liberado 38 kJ por mol de glicose convertido, neste estudo a taxa de dissipação térmica atinge valor máximo de 11,41 Wm-3 e a energia total dissipada é de 385 kJ para produzir 40 litros de cerveja. O ajuste mostrou-se satisfatório, as temperaturas máximas e os campos de temperaturas calculados apresentaram valores equivalentes aos valores experimentais.
The present study carry out a thermal analysis of beer fermentation process which aims to quantify the energy released during the process and evaluate the temperature field, using a methodology that brings together theoretical and experimental approaches. The heat dissipated during the fermentation is calculated by equations reported in the literature, with the conversion rates of glucose and CO2 production as input. These rates are calculated using the glucose concentrations measured of samples taken during tests. The dissipation is used as input in two thermal models for the calculation of temperature field. The calculated temperatures are higher than those monitored experimentally, with differences up to 78%. It supports the proposal of an adjusted equation for heat release of beer fermentation. The proposed equation indicates that 38 kJ per mol of converted glucose is released. In this study, the thermal dissipation rate reaches a maximum value of 11.41 Wm-3 and the total energy dissipated is 385 kJ for producing 40 liters of beer. The adjustment is satisfactory, the maximum temperatures and the temperature fields calculated are equivalent to the experimental values.

Em S. cerevisiae, as proteínas de membrana são responsáveis pelo transporte de açúcares através da membrana celular e, portanto, são importantes para os processos fermentativos. Visando melhorar a compreensão do metabolismo de açúcares, estudamos o transporte ativo de açúcares mediado pela permease Agt1p e o processo de inativação catabólica, promovido pela glicose. Para isso, mutantes em resíduos específicos do Agt1p foram gerados por mutagênese e expressados em uma linhagem agt1D. Os resultados obtidos indicam que os aminoácidos Glu-120, Asp-123, Glu-167, Arg-504 e Ile-505 estão envolvidos com o simporte açúcar-H+ realizado pelo Agt1p. Em relação aos resíduos e/ou domínios envolvidos com o processo de inativação catabólica, os resultados demonstram que a região N-terminal do Agt1p, bem como a alça citoplasmática presente entre os TMs 6 e 7, são essenciais para a resposta celular frente a presença de glicose. Finalmente, a fusão do Agt1p com GST permitiu purificar uma proteína de ~67 kDa, condizente com a massa molecular prevista para este transportador.
In S. cerevisiae, membrane proteins are responsible for the transport of different sugars across the cellular membrane and, therefore, are important for fermentation processes. In order to improve our understanding of sugar metabolism, we studied the active sugar transport mediated by Agt1p permease and the catabolite inactivation induced by glucose. Thus, mutants in specific residues of the Agt1p were generated by site direct mutagenesis and expressed in a strain agt1D. The results indicate that the Glu-120, Asp-123, Glu-167, Arg-504 and Ile-505 residues are involved in the sugar-H+ symport mediated by the Agt1p permease. Regarding residues and/or domains involved in the process of catabolite inactivation promoted by glucose, the results indicate that the N-terminal region of Agt1p, and the intracellular loop between TMs 6 and 7, are essential for the cellular response to the presence of glucose. Finally, the fusion of the Agt1p to GST allowed the purification of a ~67 kDa protein, consistent with the predicted molecular weight of this transporter.