Impact of full-scale brewing processes on lager beer nitrogen compounds

This paper analyses in a full-scale industrial process firstly the nitrogen compounds in all-malt and in maize-adjunct worts, then their fate during the main brewing steps and finally the influence on them of two different separation technologies: mash filter (Meura 2001) and lauter tun (Steinecker FVAS 26). Data showed that (1) maize-adjunct worts have a lower total nitrogen compounds than all-malt worts; (2) assimilable nitrogen represents 20–24% out of the total nitrogen in both all-malt and in adjunct worts; (3) free amino nitrogen nearly doubles in all-malt compared with adjunct worts; (4) proline and asparagine are the most abundant amino acids in both worts; (5) ammonium disappears during fermentation in wort with the lowest nitrogen content, i.e. in maize-adjunct wort. Moreover, the total nitrogen is reduced in all-malt by 80% with the Steinecker FVAS 26 lauter tun and 25% with the Meura 2001 filter, while in adjunct worts by 87% with the Steinecker FVAS 26 lauter tun and 29% with the Meura 2001 filter. After mash filtration, the content of assimilable nitrogen remains to be adequate for an efficient fermentation, but after lauter tun separation, the assimilable nitrogen reaches values that may compromise the regular fermentation process in both all-malt and adjunct worts. Therefore, when using lauter tun, we have to intervene to reduce its impact on nitrogen compounds and/or plan the wort nitrogen supplementation to overcome the stuck and sluggish fermentations.     

啤酒贮存过程中风味稳定性的研究

以青岛啤酒为样本,研究热力灭菌、贮存温度、溶解氧及添加氨基胍对啤酒风味稳定性的影响。结果表明,热力灭菌对啤酒的风味稳定性影响较小;贮存温度和溶解氧明显影响啤酒中5-羟甲基糠醛、B峰、史垂克醛类、TBN、DPPH还原力、色度等风味稳定性指标的浓度;啤酒中添加氨基胍能明显降低5-羟甲基糠醛、双乙酰、2,3-戊二酮等羰基化合物的含量,提高啤酒的风味稳定性。     

啤酒酿造过程中泡沫蛋白质的变化研究

泡沫蛋白质是啤酒泡沫的骨架,其含量和性质很大程度上决定了啤酒泡沫的质量.蛋白质Z和脂转移蛋白(LTP)是啤酒泡沫蛋白质中的关键组分,实验究考察了啤酒酿造过程中泡沫蛋白质的变化过程.结果显示:在糖化过程中,分子量为53ku及20～40ku的蛋白质被分解,蛋白质Z及LTP的含量没有太大变化;麦汁煮沸过程中蛋白质含量逐渐减少,蛋白质Z、LTP1和LTP2分别减少了11％、32％及26％;主酵过程中,蛋白质Z、LTP1和LTP2的降幅较大,分别为12％、59％和31％;后酵过程中,蛋白质Z和LTP1的含量基本不变,LTP2的含量逐渐降低,到后酵结束,LTP2的降低幅度达22％.     

Primary odorants of pale lager beer

Summary Application of an aroma extract dilution analysis to the flavour concentrate of a pale lager beer revealed 33 primary odorants (FD factors ranging over 16 to 1024) among which 3-methylbutanol, 2-phenylethanol, 4-vinyl-2-methoxyphenol, 3- and 2-methylbutanoic acid, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (furaneol) and butanoic acid showed the highest FD factors. With a somewhat lower FD factor ethyl butanoate, 4,5-dimethyl-3-hydroxy-2(5H)-furanone (sotolone), ethyl hexanoate, hexanoic acid and (E)--damascenone contributed to the overall flavour. Compared to the pale lager beer, the odour activity value (OAV; ratio of concentration to odour threshold) of furaneol in a dark lager beer and of 4-vinyl-2-methoxyphenol in a wheat beer, was significantly higher. Sensory experiments corroborated that these odorants were important contributors to the overall flavour of the dark lager and the wheat beer, respectively. In two alcohol-free beers the OAVs of eight of the most important odorants were markedly lower. After storage of a pale lager beer (14 d; 40° C), which had been spiked with oxygen, the FD factors of most of the primary odorants of the fresh beer remained unchanged. On the other hand, phenylacetaldehyde, 3-methyl-3-mercaptobutylformate (catty,Ribes odour) and an unknown compound with a sweet, aniseed-like note appeared as additional important odorants in the stored sample.

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Primäre Geruchsstoffe in hellem Vollbier. Unterschiede zu anderen Biertypen und Veränderungen bei der Lagerung

Zusammenfassung Die Aromaextraktverdünnungsanalyse der flüchtigen Verbindungen aus hellem Vollbier ergab 33 primäre Geruchsstoffe (FD-Faktor-Bereich 16-1024) unter den 3-Methylbutanol, 2-Phenylethanol, 4-Vinyl-2-methoxyphenol, 3- und 2-Methylbuttersäure, 2,5-Dimethyl-4-hydroxy-3(2H)-furanon (Furaneol) und Buttersäure die höchsten FD-Faktoren aufwiesen. Mit etwas niedrigeren FD-Faktoren waren Buttersäureethylester, 4,5-Dimethyl-3-hydroxy-2(5H)-furanon (Sotolon), Capronsäureethylester, Capronsäure und (E)--Damascenon am Gesamtaroma beteiligt. Im Vergleich zu hellem Vollbier waren die Aromawerte (berechnet aus Konzentration und Geruchsschwellenwert) von Furaneol in dunklem Vollbier sowie von 4-Vinyl-2-methoxyphenol in Weizenbier signifikant höher. Sensorische Untersuchungen bestätigten, daß diese Geruchsstoffe einen wichtigen Beitrag zum Aroma des dunklen Bieres bzw. des Weißbieres leisten. In zwei alkoholfreien Bieren waren die Aromawerte von acht der wichtigsten Aromastoffe deutlich niedriger. Nach der Lagerung eines hellen Vollbieres (14 Tage; 40°C) in Gegenwart von Sauerstoff veränderten sich die FD-Faktoren der meisten primären Aromastoffe des frischen Bieres nicht. Andererseits traten Phenylacetaldehyd, 3-Methyl-3-mercaptobutylformiat (Geruch nach Katzenurin) und eine unbekannte Verbindung mit einer süßen, anisartigen Note als zusätzliche wichtige Aromastoffe in der gelagerten Probe auf.

     

Determination of dimethyl sulphide in beer and lager

A gas chromatographic method is described for the determination of dimethyl sulphide in beer. The peak height of the dimethyl sulphide is compared with that of an n-butanol standard and the concentration calculated using their relative response factors. When authentic dimethyl sulphide was added to beer good recoveries (99% average) were obtained. Determination of the reproducibility from duplicate analyses of beer samples gave an average coefficient of variation of 7.7 % for the concentration range of 0-35 μg/l.     

Photocatalytic degradation of selected s-triazine herbicides and organophosphorus insecticides over aqueous TiO2 suspensions

The photocatalytic degradation of selected s-triazine herbicides and organophosphorus insecticides was carried out in aqueous TiO2 suspensions under simulated solar light. The tested herbicides from the s-triazines group were atrazine, propazine, cyanazine, prometryne, and irgarol. The tested insecticides from the organophosphorus group were ethyl parathion, methyl parathion, ethyl bromophos, methyl bromophos, and diclofenthion. Degradation kinetics followed first-order reaction and has been monitored through gas chromatography. The degradation was fast with half-lives varying from 10.2 to 38.3 min depending on the nature and the structure of compounds. The generated transformation products (TPs) were formed via oxidation, dealkylation, and dechlorination for s-triazines and via oxidation and photohydrolysis for organophosphates. The TPs of irgarol, bromophos, and dichlofenthion were identified using solid-phase extraction (SDB-disks) and GC-MS techniques, and possible degradation routes were proposed showing similar degradation pathways as for other triazines and organophosporus pesticides. This work points out to the necessity of extended knowledge of the successive steps in a solar-assisted detoxification process.     

啤酒发酵过程中有害菌对双乙酰含量影响的分析

双乙酰是影响啤酒风味的重要因素.啤酒发酵过程中双乙酰含量先升高后下降.该文通过对啤酒发酵过程中有害菌对啤酒中双乙酰的影响,深入了解双乙酰含量的变化趋势.从生产的各个环节入手进行微生物的管理和控制,以保证啤酒的微生物安全,进而稳定啤酒的质量和风味.     

啤酒发酵过程中酵母环境压力应答机制研究进展

在啤酒发酵过程中,生产高质量的啤酒要求相应的工艺条件以保证啤酒的质量以及酵母的活力。大多数的风味物质都是在后熟的过程中形成,在后熟过程中,啤酒酵母暴露在不同的压力条件下,包括渗透压、pH、酒精浓度、营养以及温度等。在长期的驯化过程中,啤酒酵母自身表现出各种压力应答机制以适应啤酒发酵过程。本论文概述了啤酒发酵过程中啤酒酵母受到的压力,重点探讨了啤酒酵母在后酵期经受的压力以及压力应答的分子机制,并对如何提高啤酒酵母环境压力应答能力进行了展望。     

现代小麦啤酒生产技术

主要介绍小麦啤酒的生产，包括小麦品种选择，麦汁制备工艺和一罐法发酵工艺。     

Effect of soy peptide on brewing beer

Here, we examined the effect of soy peptides (SPs) on the fermentation and growth of Yeast Bank Weihenstephan 34/70 (W34/70), a bottom-fermenting yeast. We compared fermentation for SP with that for a free amino acid (FAA) mixture having the same amino acid composition as SP, as a nitrogen source. Maltose syrup was used as a carbon source, and the medium contained excess amounts of essential minerals and vitamins. We observed that SP was better than FAA mixture at promoting fermentation and growth and that much more beta-phenylethyl alcohol was produced during fermentation with SP than with FAA mixture. Subsequently, we compared fermentations with the FAA mixture and selected mixtures containing various dipeptides of Phe as a nitrogen source. We found that the rates of Phe metabolism and beta-phenylethyl alcohol generation were much higher when Phe was presented as a dipeptide (Phe-Asp, Phe-Leu, or Phe-Phe) than when presented as FAA. These results show that amino acids such as Phe are absorbed more rapidly when presented as a peptide than as FAA, resulting in a more rapid production of beta-phenylethyl alcohol.     

Two-dimensional gel analysis of the proteome of lager brewing yeasts

Modern lager brewing yeasts used in beer production are hybrid strains consisting of at least two different genomes. To obtain information on the identity of the parental strains that gave rise to industrial lager yeasts, we used two-dimensional (2-D) gel electrophoresis and analysed the proteomes of different Saccharomyces species isolated from breweries. We found that the proteome of lager brewing yeasts and of the type strains of S. carlsbergensis, S. monacensis and S. pastorianus can be interpreted as the superimposition of two elementary patterns. One originates from proteins encoded by a S. cerevisiae-like genome. The other corresponds to a divergent Saccharomyces species whose best representative is a particular S. pastorianus strain, NRRL Y-1551. A map of industrial lager brewing yeasts has been established, with the individual origin of proteins and with identification of protein spots by comparison to known S. cerevisiae proteins. This 2-D map can be accessed on the Lager Brewing Yeast Protein Map server through the World Wide Web. This study provides the first example of the use of proteome analysis for investigating taxonomic relationships between divergent yeast species.     

啤酒酿造中厌氧菌的控制

浅谈啤酒生产过程中厌氧菌的特性以及我公司控制厌氧菌的具体措施。     

抗氧化系统在啤酒酿造中的应用研究

介绍了氧、氧自由基在啤酒酿造中的作用,从自由基的角度对啤酒氧化的本质进行了诠释,并探讨了啤酒抗氧化物质及其作用机制,总结了国内外关于啤酒风味老化的各种评价指标及方法。     

小麦啤酒的生产工艺

小麦啤酒以其特殊的小麦芽香气,风味上较普通大麦啤酒有显著特点,深受消费者的青睐。小麦啤酒(wheatbeer)是指以小麦为全部或者大部分原料所生产的一类啤酒,小麦麦芽和大麦麦芽相比具有较高的蛋白质含量,从而具有很好的泡持力,但是由于小麦麦芽本身固有的特性(裸麦、蛋白含量高),使得小麦啤酒制备过程中过滤困难,制成的小麦啤酒非生物稳定性较差。结合本文对国内外现行的小麦啤酒生产技术、工艺所作的综述,可以从小麦啤酒的生产工艺方面来着手解决以上难题。     

酿造单宁在啤酒生产中应用

随着市场竞争的日趋激烈和啤酒技术的飞速发展,啤酒的保鲜期及非生物稳定性,成为酿造工作者所致力于研究的课题。酿造单宁对于成品啤酒抗老化性能、改善啤酒风味和提高保质期具有较好的应用前景。     

Diffusion of organophosphorus insecticides in soils

Diffusion of disulfoton and dimethoate in a silt loam soil was studied over a range of concentrations and moisture contents. Apparent diffusion coefficients were calculated from the distribution of insecticide in a column of soil after diffusion from one half of the column to the other for a known time. The distribution was determined by slicing the column into narrow; sections using a specially constructed diffusion cylinder. Diffusion coefficients varied little with concentration for both insecticides, but increased rapidly with increasing moisture content for dimethoate from 3.31 × 10^?8 cm²/sec at 10% volumetric moisture content to 1.41 × 10^?6 cm²/sec at 43% moisture content. In contrast, for disulfoton which is more volatile, less soluble and more strongly sorbed than dimethoate, diffusion coefficients were smaller (2.83 × 10^?8 cm²/sec at 41% moisture content) but did not change much as the soil became drier (2.74 × 10^?8 cm²/sec at 8 % moisture content). The influence of partition between solid, solution and vapour phases in the soil and of the geometry of the pathway-through the soil pores on the apparent diffusion coefficient is discussed. The likely behaviour of other pesticides is considered in the light of these results.     

小议啤酒副产物综合利用

随着我国啤酒产量的连年增加,啤酒副产物也相应增加,本文就近期国内外综合利用啤酒副产物的主要成果作一综述。     

Effects of high hydrostatic pressure on shelf life of lager beer

Filtered bright lager beer samples were either treated with high hydrostatic pressure (HHP, 350 MPa for 3 and 5 min at 20 °C) or conventional heat pasteurization (60 °C for 15 min). A storage period of 56 days showed that HHP and heat pasteurization had similar results in terms of pH and color (p<0.05). However HHP-treated samples had lower bitterness and protein sensitivity and higher chill haze values than the heat pasteurized samples at the end of the storage period. The microbiological stability of HHP-treated beers was the same as that of heat-treated beers, and the development of both lactic and acetic acid bacteria was inhibited for 56 days of storage. Although more studies should be carried out to investigate the effects of HHP treatment on different types of lagers and ales, our results revealed that HHP could be successfully used to increase the shelf life of beer even at temperatures well below those required for heat pasteurization.     

酒花萜烯醇及其立体异构体在啤酒酿造中的检测及其变化研究

采用顶空固相微萃取-气相色谱质谱技术(HS-SPME/GC-MS),跟踪检测了啤酒酿造过程中(R)-(-)-里那醇、S-(+)-里那醇、(R)-(+)-β-香茅醇、(S)-(-)-β-香茅醇、(+)-α-萜品醇、(-)-α-萜品醇、香叶醇、橙花叔醇等12种香气化合物。通过控制酿造过程中不同的香花添加工艺,发现在煮沸结束、回旋沉淀槽及主酵结束后添加香花工艺较煮沸结束前10 min添加工艺,能显著提高萜烯醇及其立体异构体保留在啤酒中的含量,其中对酒花香气具有重要贡献的四种萜烯醇:R-(-)-里那醇、香叶醇、R-(+)-β-香茅醇及橙花叔醇在啤酒中的含量范围分别为1.94¹4.39μg/L、9.8314.39μg/L、9.83¹2.10μg/L、2.9112.10μg/L、2.91⁶.79μg/L、5.346.79μg/L、5.34⁶.81μg/L,它们的风味强度OAV值范围在0.296.81μg/L,它们的风味强度OAV值范围在0.29⁶.54,并对上述4种物质在啤酒发酵过程中的变化规律展开了进一步探究。结合感官评品结果显示,发现回旋沉淀槽添加香花工艺最好,主酵结束后添加香花工艺次之。     

小麦啤酒酿造工艺条件的探讨

以优质小麦芽为主要原料,通过科学方法精心酿制成低度饮料酒,色度较淡,口味清爽,营养丰富,风味纯正、独特。本文结合生产工艺过程介绍了小麦啤酒的特点、酿造工艺务件及操作要点。