Beer Processing Research Articles

Detection of Mannan from Saccharomyces Cerevisiae by Flow Cytometry

Mannan plays an important role in the formation of some beer hazes. The effects of mechanical agitation of Saccharomyces cerevisiae brewing strains and subsequent impact on beer quality were investigated. Six different brewing yeast strains (ale and lager) were subjected to mechanical agitation in a temperature-controlled bioreactor. As a result of this study, a protocol is described for the determination of mannan residues from S. cerevisiae cells in nearly real time. Flow cytometric methods permitted the quantitative analysis of mannan residues based on particle size, relative granularity, and florescence intensity. The mannan concentrations and optical density of its supernatant increased as the yeast slurry was agitated. It was concluded that hydrodynamic stresses from agitation of yeast slurries cause mannan, an unfilterable haze constituent, to be released from the yeast cell wall. Furthermore, flow cytometry provides an innovative, rapid, and viable option for quantifying the influence that beer processing conditions have on beer stability.

Characterization of a flocculation-like phenotype in Cryptococcus neoformans and its effects on pathogenesis

We investigated the phenomenon of cell-cell aggregation (flocculation) in a serotype D strain of Cryptococcus neoformans (ATCC 24067, isolate RC-2). Cell aggregation into clumps of 5-40 cells (clump+ cells) occurred during the early log phase and disappeared in the beginning of the stationary phase (clump- cells). The cell aggregation phenomenon was medium dependent. Clump+ cells could be dispersed by either vortexing or proteinase K digestion. Most importantly, the transient change in cellular phenotype changed several important host-pathogen interactions. Adherence of clump+ cells to murine macrophage-like cells J774.16 was significantly (P < 0.001) enhanced compared with adherence of clump- cells. Furthermore, complement-mediated phagocytosis efficacy of dispersed clump+ cells was significantly higher (P < 0.001) compared with clump- cells. Similar findings were documented with an in vivo phagocytosis assay. Infection of mice with a low inoculum (10(4)) of clump+ cells resulted in lower fungal burden when compared with mice infected with clump- cells. Accordingly, mice infected with clump+ cells survived significantly longer than mice infected with clump- cells. These results indicate that the cellular phenotype undergoes significant changes that result in a transient flocculation-like phenotype. We hypothesize that this cell-cell aggregation is the result of changes in protein content in the polysaccharide capsule. We conclude from our data that the change in cellular phenotype has a dramatic effect on cell adherence, and on complement-mediated phagocytosis, both of which can affect the pathogenesis of the disease in the host. Our results underscore the complexity of studies that investigate host pathogen interactions and may explain differences and inconsistencies observed in in vitro and in vivo assays.

Influences of pH and hydraulic retention time on anaerobes converting beer processing wastes into hydrogen

To convert high-solids organic wastes (3% w./w.) to high-value hydrogen, a full factorial experimental design was employed in planning the experiments for learning the effects of pH and hydraulic retention time (HRT) on the hydrogen production in a chemostat reactor using waste yeast obtained from beer processing wastes. For determining which experimental variable settings affect hydrogen production, predictive polynomial quadratic equation and response surface methodology were employed to determine and explain the conditions required for high-value hydrogen production. Experimental results indicate that a maximum hydrogen production rate of 460 mL/gVSS/d was obtained at pH = 5.8 and HRT = 32 hours. Moreover, hydrogenase targeted RT-PCR results indicate that Clostridium thermocellum and Klebsiella pneumoniae predominated.

Pulsed Electric Field Processing of Beer: Microbial, Sensory, and Quality Analyses

ABSTRACT: In this study, pulsed electric field (PEF) treatment of beer, effectiveness of PEF treatment on microbial inactivation, effects of PEF treatment on sensory properties, and detection of electrode material migration were explored. Beer samples were treated by PEF for the inactivation of natural flora and inoculated cultures of Saccaromyces uvarum, Rhodotorula rubra, Lactobacillus plantarum, Pediococcus damnosus, and Bacillus subtilis. Inactivation induced by the PEF treatment was 0.5, 4.1, 4.3, 4.7, 5.8, and 4.8 log10 colony‐forming units/mL in the above microorganisms, respectively (P &lt; 0.05). There was a significant increase in the amount of Cr, Zn, Fe, and Mn ions in the beer samples after PEF treatment (P &lt; 0.05) leading to a statistically significant degradation in flavor and mouth feel. Further studies are needed to optimize electrode materials and PEF treatment to minimize or eliminate this degradation.

Variation of sorghum phenolic compounds during the preparation of opaque beer

Phenolic compounds affect the rate of fermentation, quality and stability of opaque beer produced from sorghum. The levels of proanthocyanidins (PAs) were determined photometrically at various stages during the preparation of opaque beer from high polyphenol sorghum. Decreases in the levels of proanthocyanidins were 52 and 34% during the lactic and second alcoholic fermentation stages, respectively. Quantitative and qualitative changes in the low molecular weight phenolic compounds of sorghum during the preparation process of opaque beer were determined by gas chromatography coupled with mass spectrometric detection. The main low molecular weight phenolic compounds detected in sorghum malt were p-hydroxybenzoic acid, p-hydroxybenzaldehyde and p-hydroxybenzoyl alcohol. Levels of p-hydroxybenzaldehyde decreased during both lactic acid and alcoholic fermentation while the levels of p-hydroxybenzoic acid and p-hydroxybenzoyl alcohol increased during alcoholic fermentation. Protocatechuic acid, caffeic acid and p-coumaric acid were detected at relatively low levels at various stages of opaque beer preparation.

Optimisation of Steeping Program in Malt Industry

Abstract Malt is the major cereal grain used in beer processing. It results from the transformation of Barley along the three main steps of the malting process: steeping, germination and kilning. The malt quality is strongly correlated to the set-up of the steeping phase. The later consists of 2 or 3 sequential cycles of wet steeps and air rests. In this work the steeping program durations which optimise the malt quality, expressed as friability, are determined. In order to perform this optimisation, a mathematical model is constructed using an iterative experimental design. Both model and the resulting optimal steeping conditions are experimentally validated.

Thermal Convection in Cylindro-Conical Tanks During the Early Cooling Process

Industrially it is important to understand the cooling process of beer in cylindro-conical tanks (CCTs) in regard to energy efficiency and to the maturation of beer from 10°C to 0°C. However the cooling process is a complicated phenomenon. We have previously studied thermal convection in a miniature CCT constructed of transparent acrylic resin (ACCT) and found that thermal convection was not uniform, but rather wavy in the circumferential direction. In this report thermal convection was studied in a CCT constructed of metal and enlarged to the 500 L size. The water temperature in the CCT was measured by thermosensors and the surfaces visualized using an infrared camera. We confirmed that both 500L CCT and ACCT have qualitatively similar flow from 10°C to below 4°C. Although there are size effects between small CCTs and large CCTs, experiments with the smaller CCT gave useful information on the early cooling process. An infrared camera was employed to investigate the state of convection and gave information on how to effectively refrigerate beer.

Application of high‐pressure treatment in the mashing of white malt in the elaboration process of beer

AbstractIn this study, high‐pressure treatment (HPT) was applied to the mashing stage of beer production, which involves drying and milling of white malt and subsequent mixing with water. The following parameters were evaluated after pressurisation: β‐glucanase activity, starch gelatinisation and sugar extraction. Evaluation of starch hydrolysis from the malted barley endosperm after HPT was performed by measuring β‐glucanase activity after pressurisation; this enzyme breaks down gums and β‐glucans in wort and is desirable to obtain a good‐quality beer. Soaked malt samples pressurised at 200–600 MPa showed no increase in this activity compared with controls. Conversion of milled malt was evaluated indirectly by measuring the gelatinisation of starch, which began at 400 MPa. Soluble sugars were also measured in pressurised samples from the mashed liquid to investigate saccharification during the mashing stage. After 400 or 600 MPa treatment for 20 min, both the sucrose (g per 100 ml) and extract (l ° kg−1) values were the same as those found in mashed samples following the standard procedure used in the brewing industry (65 °C,90 min). Starch gelatinisation was analysed at different high pressures (200–600 MPa) and it was shown that gelatinisation began at 400 MPa. The HPT time would have to be shorter to make the process commercially attractive.© 2002 Society of Chemical Industry

Evidence of the glycation and denaturation of LTP1 during the malting and brewing process.

The influence of malting and brewing processes on the chemical and structural modifications occurring on LTP1 was investigated by mass spectrometry and circular dichroism. Proteins were first purified from malt, and samples were collected at various steps of beer processing performed on two barley cultivars. The levels of LTP1 found in malt were not significantly different from the amounts in barley seed. However, in malt, both LTP1b, a post-translational form of LTP1, and a third isoform named LTP1c were isolated. Moreover, both of these proteins were found to be heterogeneously glycated but still exhibited an alpha-helix structure. Both glycated LTP1 and LTP1b were recovered during mashing. It was also shown that glycated LTP1 was unfolded during heat treatment of wort boiling, which is in agreement with the denatured form previously isolated from beer.

110ビール貯酒タンク模型を用いた研究

We have used lagertanks in the storage process of beer, and the shape of lagertank is cylindro-conical. The outer wall of the tank is cooled for maturing beer during the storage process with experienced control system. However the cooling process in the tank is hardly known, so we have studied the cooling process with cylindro-conical mini-tank. Here we report the cooling process based on the visualization and the measurement of temperature in the tank.

A comparison of sequencing rules in static and dynamic hybrid flow systems

It is well known that efficient scheduling of jobs is essential for improving the economics of production in manufacturing organizations. As a result, extensive research has been conducted on scheduling, especially in job shop and flow shop settings. In contrast, little research has been done on hybrid flow systems, even though they are found in many industries, including beer processing, glass container production, pertroleum refining, plastic-coated cable production, and fertilizer production. Furthermore, the few studies that have dealt with hybrid systems have been limited by the assumptions made about their operating environments. Therefore, we conducted a study that extends the previous work on hybrid systems in two significant ways: (1) it included financially oriented scheduling rules and a new, related performance measure; and (2) the new rules were compared with the existing ones in a large simulation experiment under both static and dynamic (generally encountered in practice) hybrid flow shop environments. To date such comparisons have been made only under static environments. The results show that the relative performances of the scheduling rules differ as the assumptions regarding the operating environment are changed.

Beer's ?organizational tensegrity? and the challenge of democratic management

Many systems scientists are keenly interested in the democratization of management, particularly in the development of better processes for democratic decision making. Stafford Beer's recent development of a consensus decision-making process based on “organizational tensegrity” is an exciting contribution in this area, which also has important implications for the design of democratic organizational structures. This paper describes some experimentation with these ideas (with assistance from Beer) in two work groups at Pacific Bell and explores the potential of Beer's process for democratic management.

Beverage stabilization through enzymatic removal of phenolics

Abstract In the production of beverages such as wine, fruit juice and beer, the removal of phenolics (coumaric acids, flavans, antho‐cyanins ) in order to prevent discoloration, haze and flavour changes is a regular practice based on the addition of proteins, adsorbants and PVPP (polyvinylpolypyrrolidone). In this experiment, Laccase, Tannase and Peroxidase were separately added to grape musts and barley worts in order to ascertain the effectiveness of their use as stabilizer in wine and beer processing. The effects of Laccase were examined more closely, as this enzyme acts on a wide range of phenolics in these beverages and at an adequate pH level. Some positive results seem to confirm the potential usefulness of either Laccase and Tannase as a pre‐fermentative treatment, coupled with conventional fining.

Determination of Tannic Acid in Beer by High Performance Liquid Chromatography

Accurate, simple methods are needed to determine tannic acid (gallotannin), which is present endogenously in many foods and fermented beverages such as wine and cider. A method complementary to thin-layer chromatography (TLC) uses high performance liquid chromatography (HPLC) on Corasil-II, with a multisolvent gradient system. The calibration curves are made with both monomeric and dimeric gallic acid. The latter is isolated from tannic acid by preparative HPLC and identified by nuclear magnetic resonance spectroscopy and TLC. Tannic acid is then determined in a beer ethyl acetate extract by quantitative chromatography of its gallic and digallic acid components. Because endogenous digallic acid has not been reported in beer, determination of this component in beer confirms the presence of tannic acid and its use in beer processing. The HPLC method offers an alternative to the TLC method and can be used to confirm TLC results.

Determination of Tannic Acid in Beer by High Performance Liquid Chromatography

Accurate, simple methods are needed to determine tannic acid (gallotannin), which is present endogenously in many foods and fermented beverages such as wine and cider. A method complementary to thin-layer chromatography (TLC) uses high performance liquid chromatography (HPLC) on Corasil-II, with a multisolvent gradient system. The calibration curves are made with both monomeric and dimeric gallic acid. The latter is isolated from tannic acid by preparative HPLC and identified by nuclear magnetic resonance spectroscopy and TLC. Tannic acid is then determined in a beer ethyl acetate extract by quantitative chromatography of its gallic and digallic acid components. Because endogenous digallic acid has not been reported in beer, determination of this component in beer confirms the presence of tannic acid and its use in beer processing. The HPLC method offers an alternative to the TLC method and can be used to confirm TLC results.

USE OF PAPAIN IMMOBILIZED ON SPHEROSIL FOR BEER CHILLPROOFING

ABSTRACTPapain has been immobilized on Spherosil, a porous silica, by two methods: reaction with glutaraldehyde activated amino groups and direct bonding to acetal groups. Both amino and acetal groups were grafted onto the silica via silane coupling. Best results were given by the second method. This derivative was used on a 1‐L packed bed reactor for continuous processing of beer produced by a fermentor using immobilized Saccharomyces uvarum cells. The papain reactor was effective for on‐line beer chillproofing, as measured by the sensibility of the beer to tannin addition.

Development of a recovery process for novobiocin.

AbstractA periodic countercurrent whole beer process was developed for the recovery of novobiocin to eliminate the high cost of mycelium filtration and accompanying antibiotic losses in the filter cake. In such a process screened, but unfiltered, novobiocin fermentation beer is contacted with a special grade of an anionic‐exchange resin in a series of specially designed, well mixed columns. Each column is fitted with a screen sized to retain resin within the column but allow the cells to press. Periodically the lead column is isolated from the column train, washed free of beer solids, and eluted. A freshly eluted column is placed in the trail position to allow countercurrent operation. The eluate is then processed to crystalline product.A mathematical model for the sorption of novobiocin was developed based on a suitable continuity equation and mass transfer and equilibrium relationships determined in the laboratory. Digital computations of this model correlated well with laboratory and pilot plant data, and predicted well the performance of the production units. This simulation has been in continued use to predict and reoptimize plant operation as process changes (such as improved beer titers, increased production rate, and the evaluation of superior ion‐exchange resins) occurred or were anticipated.

Food Processing with Added Ascorbic Acid

The use of L-ascorbic acid in processing food was reviewed by Bauernfeind in 1953. By that time, several hundred papers had already been published on studies of various applications of this compound in food processing. L-Ascorbic acid, a 6-carbon compound and a water-soluble vitamin also known as vitamin C (for cevitamic acid), exists in both the reduced and the oxidized forms (dehydroascorbic acid) in nature. It is found in all living tissues. Citrus fruits, tomatoes, potatoes, and cabbage are the important natural dietary sources for man, but content varies depending on variety, environmental factors, and processing. L-Ascorbic acid (vitamin C) is added to processed fruit, vegetables, meat, fish, milk, fats, oils, flour, soft drinks, malt beverages, wine, confections, and synthetic foods. It may be added to enhance nutritional value, or to improve keeping qualities, color, stability, palatability, clarity, or baking quality. This chapter looks at ascorbic acid as an added nutrient. The use of L-ascorbic acid to inhibit or prevent undesirable oxidative changes in the processing of foodstuffs has been largely empirical. It discusses ascorbic acid as synergist in fat protection, preventive of fruit browning, preventive of vegetable discolorations, inhibitor of oxidative rancidity in fish, stabilizer of meat color, flour or bread improver, oxygen acceptor in beer processing, reducing agent in wine, oxidation inhibition in dairy products, and other miscellaneous uses. The use of ascorbic acid in a nutrient capacity or as a food processing aid is subject to government regulation in many countries. The status of ascorbic acid addition in each instance of desired use should be determined by consulting the pertinent regulation. A brief review of the regulatory requirements in some countries is given here. This chapter ends with the discussion of L-Ascorbic acid vs. erythorbic acid.