Influence of temperature on continuous high gravity brewing with yeasts immobilized on spent grains

Flavor compounds’ formation and fermentative parameters of continuous high gravity brewing with yeasts immobilized on spent grains were evaluated at three different temperatures (7, 10 and 15 °C). The assays were performed in a bubble column reactor at constant dilution rate (0.05 h−1) and total gas flow rate (240 ml/min of CO2 and 10 ml/min of air), with high-gravity all-malt wort (15°Plato). The results revealed that as the fermentation temperature was increased from 7 to 15 °C, the apparent and real degrees of fermentation, rate of extract consumption, ethanol volumetric productivity and consumption of free amino nitrogen (FAN) increased. In addition, beer produced at 15 °C presented a higher alcohols to esters ratio (2.2–2.4:1) similar to the optimum values described in the literature. It was thus concluded that primary high-gravity (15°Plato) all-malt wort fermentation by continuous process with yeasts immobilized on spent grains, can be carried out with a good performance at 15 °C.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Optimization of ethanol production from cheese whey powder by Kluyveromyces fragilis using factorial design and response surface methodology

The individual and combined effects of initial lactose concentration, temperature and inoculum concentration on ethanol production from cheese whey powder by Kluyveromyces fragilis were investigated. A 2 3 full-factorial central composite design (CCD) and response surface methodology (RSM) were employed in order to determine the optima conditions that maximize the ethanol production. Statistical analysis of results showed that, in the range studied, only the initial lactose concentration had a significant effect on ethanol production. Response surface data showed maximum ethanol production at inoculum concentration between 1 and 3 g/L and temperature between 25 and 35ºC when the initial lactose concentration was 150 g/L.CAPES/Grices - BEX2150/07-7

Optimal fermentation conditions for maximizing the ethanol production by Kluyveromyces fragilisfrom cheese whey powder

Cheese whey powder (CWP) is an attractive raw material for ethanol production since it is a dried and concentrated form of CW and contains lactose in addition to nitrogen, phosphate and other essential nutrients. In the present work, deproteinized CWP was utilized as fermentation medium for ethanol production by Kluyveromyces fragilis. The individual and combined effects of initial lactose concentration (50-150 kg m-3), temperature (25-35 ºC) and inoculum concentration (1-3 kg m-3) were investigated through a 23 full factorial central composite design, and the optimal conditions for maximizing the ethanol production were determined. According to the statistical analysis, in the studied range of values, only the initial lactose concentration had a significant effect on ethanol production, resulting in higher product formation as the initial substrate concentration was increased. Assays with initial lactose concentration varying from 150 to 250 kg m-3 were thus performed and revealed that the use of 200 kg m-3 initial lactose concentration, inoculum concentration of 1 kg m-3 and temperature of 35 ºC were the best conditions for maximizing the ethanol production from CWP solution. Under these conditions, 80.95 kg m-3 of ethanol was obtained after 44 h of fermentation.The authors acknowledge the financial support from "CAPES/Grices (BEX2150/07-7) and Lactogal for supplying cheese whey powder

Review : beer production : spoilage microorganisms and detection methods

A cerveja é uma bebida que apresenta características desfavoráveis para a multiplicação de vários microrganismos, sendo reconhecida como um produto de considerável estabilidade microbiológica. Porém, algumas espécies de microrganismos, incluindo bactérias Gram-positivas (Lactobacillus e Pediococcus), Gram-negativas (Pectinatus e Megasphaera) e leveduras selvagens (Saccharomyces e não-Saccharomyces) são capazes de se multiplicar nesta bebida, conferindo características indesejáveis, tais como turbidez e mudanças sensoriais, as quais prejudicam a qualidade do produto final. Este fato tem motivado uma série de pesquisas visando ao desenvolvimento de métodos rápidos e específicos para a detecção dos microrganismos deteriorantes da cerveja. Apesar de a detecção desses microrganismos, por cultivo em meios de laboratório, nem sempre proporcionar a especificidade e sensibilidade requerida, o uso de diferentes meios seletivos e condições de incubação continua sendo o método preferido pelas cervejarias. O presente artigo apresenta uma revisão da literatura sobre os principais microrganismos deteriorantes da cerveja, incluindo as causas que favorecem sua multiplicação e os métodos que podem ser empregados para sua detecção.Beer is a beverage that presents unfavourable features for the growth of several microorganisms, being recognized as a product of considerable microbiological stability. However, some species of microorganisms, including Gram-positive (Lactobacillus and Pediococcus) and Gram-negative bacteria (Pectinatus and Megasphaera) and wild yeasts (Saccharomyces and non-Saccharomyces) are able to grow in this beverage, providing undesirable characteristics, such as turbidity and sensory changes, which damage the quality of the final product. This fact has motivated a number of research projects aiming at the development of fast and specific methods for the detection of beer spoilage microorganisms. Although the detection of these microorganisms by cultivation in laboratory media does not always provide the required specificity and sensibility, the use of different selective media and incubation conditions still represent the method preferred by breweries. The present article is a literature review about the main beer spoilage microorganisms, including the causes that favour their growth and the methods that can be used for their detection

Continuous beer fermentation with yeast immobilized on alternative cheap carriers and sensorial evaluation of the final product

Continuous beer fermentation offers a wide range of advantages, mostly of economic nature over the traditional batch process. However, due to increased complexity of operation comparing to batch process, flavor problems, risk of contamination, yeast viability, carrier price and inconvenience of immobilization, the continuous beer fermentation has found few practical applications so far. The carrier cost represents a significant part of the investment costs and therefore the need for a cheap support material easy to regenerate is still relevant. This work deals with a complete continuous fermentation system for beer fermentation and maturation consisting of an airlift and a packed-bed reactor containing brewing yeast immobilized on spent grains and corncobs, respectively. The objective of this study was to verify the long-term performance of the system and the suitability of these new cellulose-based carrier materials made from brewing and agricultural by-products. Further the influence of feed rate and aeration rate on bioreactors fermentation performance, immobilized biomass load, ethanol production and flavor profile of both green and maturated beer was followed. The influence of process parameters on sensorial quality of beer has been studied by physicochemical methods as well as by sensorial analysis (acceptance and description tests) carried out by both consumers and experienced tasters. This work clearly demonstrated the technological feasibility of the continuous brewing based on yeast immobilization on cheap alternative carriers (spent grains, corncobs) for continuous production of a beer with a balanced flavor profile.Fundação para a Ciência e a Tecnologia (FCT) - SFRH / BPD / 3541 / 2000.Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) - Proc. 00/12767-4.Unicer SA.

High gravity batch and continuous processes for beer production: evaluation of fermentation performance and beer quality

This study deals with two innovative brewing processes, high gravity batch and complete continuous beer fermentation systems. The results show a significant influence of the variables such as concentration and temperature on the yield factor of the substrate into ethanol and consequently on the productivity of the high gravity batch process. The technological feasibility of continuous production of beer based on yeast immobilization on cheap alternative carriers was also demonstrated. The influence of process parameters on fermentation performance and quality of the obtained beers was studied by sensorial analysis. No significant difference in the degree of acceptance between the obtained products and some traditional market brands was found.FAPESP; CAPES; CNPq (Brazil); Malteria do Vale, Wallerstein Industrial e Commercial, Corn Products Brasil; Johnson-Diversey; FCT/Portugal; MŠMT Czech Republic; Unicer S.A

Banana peel and grape stalk: potential of valorization through the evaluation of chemical composition and physical-chemical properties

CHISA 2008 - 18th International Congress of Chemical and Process Engineering (CD-ROM of Full Texts)Bioconversion of food processing residues (agr o-based industrial residues) in valuable products has been receiving an increasing attention in the last years. In fact, the main problem experienced by agro-based industries in several c ountries is the management of their residues. As a consequence, many research centers and government departments are preparing scientific strategies in order to develop biotechnological processes capable of transforming these residues in new bio-products or as sources of other chemicals. Most of these agro-industrial residues are lignocellulosic materials constituted basically of cellulose, hemicelluloses, and lignin. In particular, banana production is one of the main economic resources of several regions in many countries, an important crop in the tropical and sub- tropical regions and one of the most consumed fruits in the world. Grapes are other of the world’s largest fruit crops, mainly grown for direct consumption, grape juice and wine- making processes. These agricultural/industrial activities generate large amounts of residues such as banana fruit peel and grape stalk. Taking in consideration these facts, it is fundamental to know their chemical composition and physical-chemical properties, in order to evaluate perspectives of applications and improvement of procedures towards an efficient utilization of these residues. For this reason, following hydrolysis, the residues obtained were analyzed by HPLC, FTIR, TGA and DSC. Preliminary results indicate the attractiveness of these materials for further applications due to their chemical composition and physical-chemical properties: glucan and xylan contents of banana peel are 23.2 ± 0.2% and 18.9 ± 0.5%, respectively, while grape stalk contains 26.5 ± 1.5% and 16.8 ± 0.4%, respectively. These results are in agreement with those obtained with some other agro-industrial residues. These approaches offer several advantages, since the several fractions obtained from the hydrolysis of these annually produced materials can be applied as raw-materials to reduce the existence of environmentally hazardous situations and/or to increase the supply of energy or chemicals produced from renewable resourcesFCT(Portugal), FAPESP(Brazil) and CAPES/GRICES(Brazil/Portugal)info:eu-repo/semantics/publishedVersio

A new strategy for using banana as an ingredient in the brewing process

Beer is a traditionally fermented beverage made from malted grains of barley, hops, yeast, and water, while banana is an important food crop cultivated widely in tropical and subtropical areas and is one of the major fruits in Brazil. Besides, the banana is also very favorable to food industry (e.g. fermented beverages) due to its rich content on soluble solids, presence of minerals, and providing low acidity. In this context, the objective of this work was to evaluate a new strategy for using banana as adjunct to increase the fermentable sugars and to supply a specific aroma in pilot-plant brewing experiments. For this, static fermentations were conducted in a 180 L cylindrical-conical reactor using 140 L as working volume. Addition of banana was evaluated when changing the concentration of the wort from 10 to 12 ºP and from 10 to 13.5 ºP (ºP is the weight of the extract or the sugar equivalent in 100 g solution, at 20 ºC) and fermented under a constant temperature of 10 and 12.5 ºC, respectively. The results showed that the increment in the initial sugar concentration (12 to 13.5 ºP, due to the use of banana juice as adjunct), and in the temperature (10 to 12.5 ºC), increased approximately 17% the ethanol productivity. Thus, it was concluded that by using of simple preparation techniques of banana juice, banana can be used as adjunct in brewing processes, helping in the development of new products as well as in the elaboration of more concentrated worts when compared the traditional brewing worts.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Malteria do ValeCorn Products BrasilWallerstein Industrial e ComercialDiverseyLever (Brazil)Fundação para a Ciência e a Tecnologia (FCT)CAPES/GRICES (Brazil/Portugal

Sensorial evaluation of continuously fermented beer and the role of process parameters in adjusting its flavour profile

Although traditional batch overwhelmingly prevails over continuous fermentation, a breakthrough in quality and savings could be achieved by a simple, flexible and cheap fermentation system. This work deals with a complete continuous beer fermentation consisting of an airlift and a packed-bed reactor containing yeast immobilized on spent grains and corncobs, respectively. The goal was to study the influence of process parameters on bioreactor performance and flavour profile of beer. Consumers considered the continuously fermented beer to be of a regular quality. The possibility of flavour adjustments by changing the process parameters was proved by a panel of experienced tasters.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/3541/2000.MŠMT - MSM 6046137305, Czech Republic.Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP).UNICER S.A

Obtention and characterization of distilled beverage from cheese whey fermentation

O presente estudo visou a produção e caracterização de uma nova bebida alcoólica através da fermentação descontínua do soro de queijo e posterior destilação do produto fermentado. Os ensaios fermentativos foram conduzidos a 35 °C e 150 rpm por 92 h, em um bioreator de 7 L (volume total) empregando a levedura Kluyveromyces fragilis. O destilado foi separado em três frações de acordo com a concentração de etanol: a cabeça (>80% v/v), o coração (80-40% v/v) e a cauda (<40% v/v). A fração do coração foi diluída para um teor alcoólico de 40% v/v e os principais compostos voláteis (ésteres e alcoóis superiores) foram determinados por Cromatografia Gasosa com detector de ionização de chama (CG-DIC) e Cromatografia Gasosa com Espectrometria de Massa (CG-EM). A fração do coração foi também submetida a análise sensorial por um painel de julgadores treinados visando estabelecer descritores visuais, olfativos e gustativos. Com este trabalho concluiu-se que é possível obter uma bebida destilada com odor e gosto agradáveis a partir da fermentação do soro de queijo