浅谈酿造用水对啤酒酿造的影响

啤酒作为人们生活餐桌、节日庆典、朋友聚会的必备饮品之一,已经成为我们生活中饮品的一部分。啤酒中大部分成分是水,水的质量直接影响啤酒的品质和风味,世界许多知名啤酒生产企业对啤酒酿造用水都有严格的要求,因此,啤酒酿造用水也被业内人士成为"啤酒的血液"。本文从啤酒酿造用水选取入手,来探究啤酒酿造用水对啤酒酿造的影响。     

二种新的酿造用酶:脱支酶和葡聚糖酶

在低糖啤酒的生产中,采用外加酶法比传统的方法(如延长糖化休止期,使用高糖化力麦芽,往麦汁中添加糖或葡萄糖浆等)更优越,因此,酶在啤酒酿造中的应用也越来越受到人们的重视。本文介绍二种新的多糖降解酶。其一,支链淀粉酶(脱支酶),其商品名为Promozyme,可单独用于糖化、麦汁处理或发酵过程,以增加麦汁的发酵力;该酶发酵过程同霉菌α-淀粉酶一起使用时,外观发酵度可超过100％。另一种多组份碳水化合物分解酶SP-249能降解大麦和     

大米辅料对啤酒酿造的影响

我国啤酒酿造主要使用大米作为辅料,我国大米品种繁多,其品质有较大差异。贮存期间,大米的品质发生变化,不同品质的大米,不同品种的大米对啤酒酿造和啤酒特性有明显的影响。     

国外科技动态

利用啤酒糟生产淀粉酶和蛋白酶啤酒糟是啤酒生产中制造麦汁时残留在过滤机或过滤槽中的麦芽皮及糖化残渣的湿润固形物,含水75～80％,粗蛋白5％,可消化蛋白质3.5％,粗脂肪2％,可溶性无氮物10％,粗纤维1％。据日本啤酒公司中央研究所冲田等研究,     

几株啤酒酵母的筛选及发酵性能比较*

啤酒酵母是啤酒酿造的灵魂,可以直接影响啤酒品质。在啤酒酿造过程中,由于啤酒酵母被多次传代和保藏,造成优良菌种发酵性能衰退等问题,导致发酵不彻底,影响最后啤酒的风味质量。为此以8株Lager型啤酒酵母为出发菌株,通过平板分离纯化获得80株分离菌株,再经过三角瓶发酵初筛和复筛、发酵罐中试发酵实验最终获得了8株发酵性能优良的啤酒酵母。其中,6株酵母可应用于酿造双乙酰含量低于0.1 mg/L的啤酒;3株酵母发酵度高于70%,适合酿造干啤酒;1株酵母发酵度低于50%,适合酿造低醇啤酒。在风味方面:1株酵母酿造的啤酒醇酯比为3.3,啤酒酯香味较突出;另1株酵母酿造的啤酒醇酯比为4.5,啤酒高级醇含量较高。8株经过选育的啤酒酵母发酵特征明显,便于精酿啤酒厂实际应用。     

低乙醛Lager型啤酒酵母研究进展

啤酒酵母是啤酒酿造的核心,对啤酒风味及风味稳定性具有重要影响。乙醛是影响啤酒风味和风味稳定性最重要的醛类化合物,是酒精饮料中引起人类致癌的物质之一,主要通过啤酒酵母的生物代谢产生,存在于啤酒发酵过程及成品啤酒中。因此,筛选或选育优良的低产乙醛啤酒酵母菌株将成为有效解决啤酒风味稳定性的途径之一。近年来,随着基因工程技术的发展及啤酒酵母基因组的不断阐明,人们对啤酒酵母菌种改良展开了大量的研究,以期解决啤酒酿造问题,改善啤酒质量。本文对采用传统方式及基因工程手段选育低产乙醛啤酒酵母的最新研究进展进行了综述。其中,对低乙醛啤酒酵母选育的手段及策略进行了讨论并对低乙醛啤酒酵母选育的研究热点及发展趋势进行了展望。     

抗老化啤酒酵母研究进展

啤酒酵母是啤酒酿造的核心,对啤酒风味多样性及风味稳定性具有重要影响。风味稳定性是啤酒重要的质量指标之一,筛选或选育综合抗老化能力高的优良啤酒酵母菌株将成为有效解决该问题的途径之一。近年来,随着基因工程技术的发展及啤酒酵母基因组的不断阐明,人们对啤酒酵母菌种改良展开了大量的研究,以期解决啤酒酿造问题,改善啤酒质量。本文对采用传统方式及基因工程手段选育高产抗氧化物质或低产啤酒老化物质及老化前驱物的啤酒酵母的最新研究进展进行了综述。其中,对抗老化啤酒酵母的选育目标、评价方法及选育策略进行了讨论,并对抗老化啤酒酵母选育的研究热点及发展趋势进行了展望。     

信息库

1.在固定化酵母生物反应器中进行啤酒快速成熟试验 在啤酒酿造中,通常α-乙酰乳酸自然氧化成双乙酰,再由酵母将双乙酰转化成乙偶姻。这两步是同时进行的,总共约需一个月时间,其中第一步是限速的关键。加温可以加速α-乙酰乳酸向双乙酰的转化,但也会影响酵母的生活力或阻断乙醇的形成。为了加速酿造过程就需要将这两个同时进行的步骤分为前后两步进行。啤酒快速酿造法的主发酵是在固定化酵母反应器中连续进行的。生产的新鲜啤酒中,α-乙酰乳酸的浓度比常规方法生产的啤酒略高。由于啤酒酵母没有α-乙酰乳酸脱羧酶,本系统的第一步是用热处理将80％α-乙酰乳酸快速转化成乙偶姻,余下的在第二步固定化酵母反应器中由酵母转化成乙偶姻。     

大麦粒重与皮壳重的遗传分析

随着啤酒麦芽工业的发展,培育优质的啤酒大麦新品种已成为当务之急。根据国内外研究成果,酿造啤酒用大麦要求粒型中等大小、圆粒饱满、千粒重高、皮壳色淡、发芽率高、发芽整齐、皮重不高于8—9％、淀粉含量     

介绍一种新型酶制剂——β-淀粉酶

天津市工业微生物研究所研制的β-淀粉酶,从1983年研制成功后,于1984年在河北省武清县建厂试生产,即建成了我国第一个β-淀粉酶工厂,并生产了商品酶制剂,酶活力高,至今已形成年产近100吨酶制剂的生产能力。β-淀粉酶是较好的糖化剂,可用于制造饴糖、麦芽糖、麦芽糖醇、麦芽糊精、醋,以及酿造新型啤酒、白酒等已在天津新华食品厂和河     

Sorghum: a cereal with lager beer brewing potential

The potential of sorghum as an alternative substrate for lager beer brewing was recognized over five decades ago. Factors which appear to influence brewing with sorghum include: the variety of sorghum, storage time, steep period, germination time, duration and levels of temperature-time sequence of the kilning cycle and temperature-time regimes during mashing. Malts from sorghum varieties that have high diastatic power, amylase and starch contents are desirable. Soluble and insoluble amylases in grain sorghum contribute towards the hydrolysis of grain constituents during mashing. Optimizing conditions for malting, mashing and fermentation are therefore necessary for the production of acceptable sorghum lager beer. This review aims to update research results on lager beer brewing with sorghum.     

Stability of Aflatoxin B1 and Ochratoxin A in Brewing

The stability of aflatoxin B₁ and ochratoxin A in brewing was investigated by adding the purified toxins to the raw materials at 1 and 10 μg/g levels during mashing in a conventional micro-brewing process. The results indicate that both toxins are stable to heat and are insensitive to cooker mash treatment. Both mycotoxins were partially removed in the mashing and brewing processes. About 14 to 18% and 27 to 28% of the added toxins were found in the final beers brewed from starting materials containing 1 and 10 μg, respectively, of either toxin per g. The possible route of transmission of mycotoxins into beer is discussed.     

Fate of ochratoxin A in brewing.

The fate of ochratoxin A in brewing was investigated by adding (3H)ochratoxin A to the raw materials at 1- and 10-mug/g levels during mashing in a conventional microbrewing process. The results indicated that large portions (28 to 39%) of the added toxin were recovered in spent grains, with less recovery in the yeast (8 to 20%) and beer (14 to 18%). About 38 and 12% of the added toxin at levels of 1 and 10 mug/g, respectively, were degraded during brewing.     

Short communication: Brewing properties of Nigerian white and yellow malted sorghum varieties mashed with external enzymes

Both white and yellow varieties of Nigerian sorghum have good brewing properties although the white are better. Thermamyl, the industrial enzyme used by the breweries in Nigeria in mashing unmalted sorghum, influences the brewing properties of both varieties, and yields of extract are increased when a combination of malt and Thermamyl is used. The mashing of sorghum with added enzymes is therefore recommended to improve both malt and beer quality.     

Recombinant brewer's yeast strains suitable for accelerated brewing.

Four brewer's yeast strains carrying the alpha-ald gene of Klebsiella terrigena (ex. Aerobacter aerogenes) or of Enterobacter aerogenes on autonomously replicating plasmids were constructed. The alpha-ald genes were linked either to the ADC1 promoter or to the PGK1 promoter of yeast Saccharomyces cerevisiae. In pilot scale brewing (50 l) with three of these recombinant yeasts the formation of diacetyl in beer was so low during fermentation that lagering was not required. All other brewing properties of the strains were unaffected and the quality of finished beers was as good as that of finished beer prepared with the control strain. The total process time of beer production could therefore be reduced to 2 weeks, in contrast to about 5 weeks required in the conventional process.     

Properties of a thermoactive beta-1,3-1,4-glucanase (lichenase) from Clostridium thermocellum expressed in Escherichia coli

A Clostridium thermocellum gene (licB) encoding a thermoactive 1,3-1,4-beta-glucanase (lichenase) with a molecular weight of about 35,000 was localized on a 1.5-kb DNA fragment by cloning and expression in E. coli. The enzyme acts on beta-glucans with alternating beta-1,3- and beta-1,4-linkages such as barley beta-glucan and lichenan, but not on beta-glucans containing only 1,3- or 1,4-glucosidic bonds. It is active over a broad pH range (pH 5-12) and has a temperature optimum around 80 degrees C. The C. thermocellum lichenase is unusually resistant against inactivation by heat, ethanol or ionic detergents. These properties make the enzyme highly suitable for industrial application in the mashing process of beer brewing.     

Genetic engineering of brewing yeast to reduce the content of ethanol in beer

The GPD1 gene encoding the glycerol-3-phosphate dehydrogenase was overexpressed in an industrial lager brewing yeast (Saccharomyces cerevisiae ssp. carlsbergensis) to reduce the content of ethanol in beer. The amount of glycerol produced by the GPD1-overexpressing yeast in fermentation experiments simulating brewing conditions was increased 5.6 times and ethanol was decreased by 18% when compared to the wild-type. Overexpression of GPD1 does not affect the consumption of wort sugars. Only minor changes in the concentration of higher alcohols, esters and fatty acids could be observed in beer produced by the GPD1-overexpressing brewing yeast. However, the concentrations of several other by-products, particularly acetoin, diacetyl and acetaldehyde, were considerably increased.     

Effect of mashing with commercial enzymeson the properties of sorghum worts

Comparative mashing trials of sorghum showed that the enzyme complex used to convert raw sorghum in brewing produced different levels of protein breakdown but reduced foaming potentials to similar degrees. Significant improvement in foaming potentials of worts were achieved when usual mashing procedures were replaced by a two-stage mashing process where late addition of gelatinized sorghum grist re-established foam stability. This late addition of part of the gelatinized grist may limit enzymic destruction of foam-stabilizing substances.     

Effect of mashing with commercial enzymeson the properties of sorghum worts

Comparative mashing trials of sorghum showed that the enzyme complex used to convert raw sorghum in brewing produced different levels of protein breakdown but reduced foaming potentials to similar degrees. Significant improvement in foaming potentials of worts were achieved when usual mashing procedures were replaced by a two-stage mashing process where late addition of gelatinized sorghum grist re-established foam stability. This late addition of part of the gelatinized grist may limit enzymic destruction of foam-stabilizing substances.