有效检测控制啤酒中的双乙酰

双乙酰是衡量啤酒风味成熟与否的决定性指标，其含量超过其味阈值，会给啤酒带来不愉快的馊饭味，影响啤酒风味。两种检测方法比较，以方法二为好。选择的检测点有：(1)酵母对双乙酰的还原性能；(2)冷麦汁、压缩空气、接种酵母、发酵容器、管道等生产环节的微生物；(3)冷麦汁α-氨基氮；(4)冷麦汁pH值和发酵液pH值；(5)接种麦汁溶解氧；(6)酵母接种量；(7)发酵液补加酵母量；(8)清酒及成品双乙酰含量。     

提高麦汁原力对啤酒风味稳定性的影响

本文根据抗氧化假说理论，研究在糖化时添加棓丹宁螯合去除金属离子以抑制Fenton反应，减少过氧化氢的积累，抑制活性氧的产生与自由基反应；煮沸时添加亚硫酸盐增加麦汁的还原力(Chapon法)，从而提高麦汁的内源抗氧化活性，延长啤酒的风味保鲜期(RSV)。     

酿造过程对贮藏啤酒中含氮化合物的影响

本文分析了工业生产全麦芽麦汁和玉米辅料麦汁的含氮化合物,以及不同分离技术[麦汁过滤机(Meura 2001)和过滤槽(Steinecker FVAS 26)]的影响.数据表明,(1)与全麦芽麦汁相比,玉米辅料麦汁含较低的总氮化合物;(2)全麦芽麦汁和辅料麦汁的可同化氮均占总氮的20%～24%;(3)与辅料麦汁相比,全麦芽麦汁游离氨基氮几乎是其两倍;(4)脯氨酸和天冬酰胺是两麦汁中最丰富的氨基酸;(5)麦汁发酵过程中铵消失,含氮量降低.此外,对于全麦芽麦汁而言,利用过滤槽,总氮减少80%,利用过滤机,总氮减少25%;对于辅料麦汁而言,利用过滤槽,总氮减少87%,而利用过滤机,总氮减少29%.麦汁过滤后,可同化氮含量足够用于有效发酵,但经过过滤槽分离之后,可同化氮到达到一个值,该值可能影响全麦芽麦汁和辅料麦汁的正常发酵过程.因此,在使用过滤槽时,我们必须控制减少其对含氮化合物的影响,或利用麦汁氮补充来克服发酵中止和缓慢发酵.     

低压麦汁煮沸

节能是各个领域中的一个共同重要课题。啤酒工厂之40%的能量消耗在麦汁煮沸过程。探讨合理的麦汁煮沸,以节约啤酒厂的能耗,提高效益,具有重大的现实意义。目前,啤酒厂采用的麦汁煮沸有3大类型:(1)传统的常压煮沸;(2)麦汁釜外煮沸;(3)带能贮系统的低(表)压麦汁煮沸。本文对低(表)压麦汁煮沸做较详细的介绍,并与传统常压煮沸做比较。一麦汁常压煮沸系统常压麦汁煮沸系统由煮沸锅(带加热夹套或内加热器)、搅拌装置、排汽管等所组成。蒸发量每小时约10%。煮沸时间至少需90分钟。因为煮沸锅是敞口的,产生的二次     

麦汁发酵能力(极限发酵度)的测定

概述 EBC 分析委员会的会员采用合作实验,分别用两种方法:常规发酵法(对照法)和快速发酵法(快速法)来测定麦汁表观发酵度(极限表观发酵度),通过比较同一样品的结果,求出重复值(r_(95))和复验值(R_(95))。在实验中,分别分析了 EBC14th 标准麦芽和两种工业麦汁,结果是:实验室麦汁(由标准麦芽制得)采用对照法,麦汁极限发酵度平均水平为83.9%,r_(95)和 R_(95)分别为0.5%和2.9%,采用快速法,麦汁极限发酵度平均水平为82.8%,r_(95)和_(95)分别为0.9%和2.4%;而工业麦汁,采用对照法,r_(95)=0.4%、R_(95)=2.4%、极限发酵度平均水平为81.3%(麦汁 A)和82.4%(麦汁B),采用快速法,r_(95)=0.3%、R_(95)=3.5%、极限发酵度平均水平为80.5%(麦汁 A)和81.7%(麦汁 B)。就 R_(95)而言,对照法更为精确,并且所测定的极限发酵度更高,因此建议采用快速法测定麦汁的发酵能力只能作为指导。     

影响麦汁煮沸强度的主要因素

<正>煮沸强度是麦汁煮沸过程的重要技术参数,其含义为麦汁煮沸时,每小时蒸发出的水分相当于混合麦汁的百分数。麦汁煮沸强度直接影响麦汁组分、浓度、色度及可凝固氮的含量。合理控制煮沸强度对啤酒的非生物稳定性及口感具有重要意义。本文将结合煮沸强度公式煮沸强度=[混合麦汁量(L)-最终麦汁量(L)]/[混合麦汁量(L)×煮沸时间(h)]×100%,以及生产实际对影响煮沸强度的各种因素进行     

热力循环不良--影响糖化(外加热)加热煮沸

糖化锅外加热煮沸麦汁是在吸热升腾后的热力循环和煮沸泵对麦汁加压强制循环的共同作用下，不断吸热升温达到饱和温度(104℃左右)，在工艺要求时间内完成煮沸工作。在一般情况下壳程工作介质为饱和蒸汽，管程为麦汁。     

运用非常规原料和工艺生产麦汁

本文主要对用未发芽原料——国产(南斯拉夫)大麦部分代替麦芽制造麦汁进行了研究。大麦事先经过不同的处理：加热分解；添加商业用酶Termamyl进行酶解；水热法分解即挤压处理(大麦片)。经以上方法处理后，不添加任何外源酶，作为辅料替代麦芽，其比例由0％～70％，并在实验室规模做了用浸出糖化法生产麦汁的实验。结果表明，用国产大麦做辅料，比例为10％时，先经加热糊化处理后，用于生产麦汁能取得不错的效果。大麦比例大于10％时，经加热糊化后用于生产麦汁，则会降低浸出物含量。若用酶预处理大麦，再用作辅料生产麦汁，其结果则不令人满意：麦汁浸出物含量和可溶性氮含量降低，这将不利于生产高质量啤酒。大麦片作辅料部分代替麦芽，用量为50％时，麦汁能获得良好的分析质量参数。     

啤酒讲座(四) 第三讲 麦汁制造工艺(上)

第三讲麦汁制造工程(上) 麦汁制造工程,又称糖化工程,它的工艺过程分为原料粉碎、麦汁的制造、添加酒花和麦汁处理。一原料粉碎原料麦芽和麦芽辅助原料,在进行糖化前需要粉碎,是糖化工艺操作的主要部分。粉碎质量对糖化时的生物化学变化、麦汁的组成比例和原料利用率的高低都是非常重要的。 1.粉碎的目的 (1)增加原料与水的接触面积麦芽辅助原料颗粒较硬,与水的接触面积较小;     

麦芽蛋白质含量对麦汁色度的影响

通过考察近一年工艺相对较稳定的麦汁(约400锅)及相应麦芽(28批,约6000吨)的相关理化指标,用数理统计中线性回归方法证明麦芽的蛋白质含量(下称麦芽蛋白)与色度差(麦汁色度与相应麦芽煮沸色度之差)存在较明显相关关系,即麦芽蛋白明显地影响麦汁的色度,求出麦芽蛋白与色度差的线性回归方程,阐述此方程在生产实际中的应用。     

提高麦汁还原力对啤酒风味稳定性的影响

根据抗氧化假说理论 ,研究了在糖化时添加木丹宁螯合去除金属离子 ,以抑制Fenton反应 ,减少过氧化氢的积累 ,抑制活性氧的产生与自由基反应 ;煮沸时添加亚硫酸盐可增加麦汁的还原力 (Chapon法 ) ,从而提高麦汁的内源抗氧化活性 ,延长啤酒的风味保鲜期(RSV)。     

提高麦汁还原力对啤酒风味稳定性的影响

本文根据抗氧化假说理论,研究在糖化时添加掊丹宁螯合去除金属离子以抑制Fenton 反应,减少过氧化氢的积累,抑制活性氧的产生与自由基反应;煮沸时添加亚硫酸盐增加麦汁的还原力(Chapon 法),从而提高麦汁的内源抗氧化活性,延长啤酒的风味保鲜期(RSV)。     

超氧化物歧化酶改善啤酒风味稳定性的研究

超氧化物歧化酶（SOD）能够清除活性氧自由基,减少活性氧自由基氧化作用引起的危害。在啤酒酿造过程中,原料中的SOD是否对酿造过程、成品啤酒的风味稳定性产生影响以及产生什么样的影响,相关的研究较少。本文研究了制麦、糖化以及发酵过程中SOD活性的变化及其对酿造过程的影响。结果表明：麦芽SOD活性和协定麦汁的还原力之间存在显著的正相关性。向麦汁中单独添加SOD或过氧化氢酶（CAT）时,可以抑制羰基化合物的形成;SOD和CAT的协同作用可以有效提高麦汁的内源性抗氧化力。发酵前单独添加SOD、同时添加SOD与CAT后的啤酒中,反-2-壬烯醛含量比对照分别降低了12．2％和14．4％,不同程度地提高了啤酒的风味稳定性。     

新型添加剂Brewbrite在麦汁制造中的应用

对Brewbrite在麦汁中的应用进行了初步研究．通过麦汁外观和其他指标的分析。结果表明，在麦汁煮沸结束前10min添加Brewbrite 30mg／L，可以有效地澄清麦汁，降低麦汁中的可凝固性氮含量。与卡拉胶、单宁、HD-003，DHG，PVPP等添加剂相比，Brewbrite可降低麦汁和啤酒中的总多酚含量、可凝固性氮含量、麦汁色度、麦汁浊度等，减少高分子氮的比例，有助于提高啤酒的非生物稳定性。（孙悟）     

低浓度淡爽型啤酒的酿造

以改善低浓度淡爽型啤酒品质为目的 ,提出了一种新颖的低浓度淡爽型啤酒的酿造方法 .采用二次煮出二段式糖化法 ,用 70 %麦芽和 3 0 %大米的原料配比 ,提高麦芽汁中糖与非糖的比值 ,并在糖化过程中添加啤酒酵母提取物作啤酒发酵的补充氮源 .所酿造的啤酒口味纯正 ,泡沫洁白细腻 ,持久挂杯 .     

Behavior of mono-, di-, and trihydroxyoctadecenoic acids during mashing and methods of controlling their production

The behavior of mono-, di-, and trihydroxyoctadecenoic acids was investigated during laboratory-scale mashing under various conditions with a view to controlling their production. Using a malt in which the lipoxygenase activity was at only a trace level (less than 0.01 U/g) or starting the mashing at a higher temperature than that conventionally used (65 degrees C instead of 48 degrees C) significantly decreased the production of these hydroxy fatty acids. Lowering the pH of the mash to inhibit lipoxygenase activity and preventing O2 uptake by the mash using carbon dioxide were also effective in reducing the amounts of these acids produced during mashing. From the viewpoint of industrial-scale beer production, the prevention of O2 uptake by the mash was selected as an appropriate method for reducing oxidation during wort production without affecting the subsequent brewing process or the taste of the finished beer. After introducing oxidation prevention procedures, the content of trihydroxyoctadecenoic acids decreased by about 30% and the foam stability and taste were improved in commercial products brewed using less than 25% malts.     

Increased protein–thiol solubilization in sweet wort by addition of proteases during mashing

The flavour stability of beer is of major concern for breweries and is closely linked to oxidative processes in the beer. In this study, a new approach to boost the antioxidative capacity of beer was investigated. Protease treatment during mashing was performed in order to solubilize or extract more thiol‐containing protein‐derived compounds into the wort. Five different proteases were tested, and they were all capable of solubilizing increased amounts of thiols in wort during mashing but with different efficiencies. The wort was characterized by measuring total nitrogen by Kjeldahl, protein concentration by the Bradford method and protein composition by SDS–PAGE, in combination with matrix‐assisted laser desorption ionization–mass spectrometry. The results indicated that the proteases increased thiol concentrations by solubilizing thiol‐containing peptide fractions and not full‐length proteins. Copyright © 2014 The Institute of Brewing & Distilling     

Release of phenolic flavour precursors during wort production: Influence of process parameters and grist composition on ferulic acid release during brewing

In this study, the effects of mashing variables such as mashing-in temperature, time and pH, mash thickness, grist coarseness and composition, and stirring regime on the release of ferulic acid were examined. Ferulic acid is a precursor for the formation of flavour-active volatile phenols and a potent natural antioxidant in beer. Given one barley malt variety, the multitude of choice in setting various process parameters and adding brewery adjuncts during brewhouse operations can give rise to worts with widely varying ferulic acid levels. A clear difference in temperature- and pH-dependence between the release of the water-extracted and the enzymatically hydrolyzed fraction was found. The T,t-dependencies of arabinoxylan-degrading enzyme activities were correlated with ferulic acid release during mashing. Results from laboratory-scale mashing experiments were validated with those from a pilot-scale (5 h) wort production process. Enhancing the enzymatic release of phenolic flavour precursors from bound forms during mashing can greatly enhance the phenolic aroma potential of wort. Optimising this precursor release during mashing may be a means for controlling final volatile phenol levels in beer.     

TECHNOLOGICAL FACTORS OF FLAVOUR STABILITY

The flavour stability of a beer primarily depends on the oxygen content of the bottled beer, but the individual steps of wort production are of similar importance viz:-

• (a) preservation of reducing substances by avoidance of oxygen pick-up during mashing, lautering and wort boiling.
• (b) elimination of substances which are prone to react to flavour active compounds like carbonyls by good mash and wort separation procedures,
• (c) avoidance of an excessive exposure of the wort to heat, to limit the formation of Maillard reaction products and related substances.

Existing brewhouses offer some possibilities to improve the process and thus flavour stability. For analytical control Gas Chromatography and High Performance Liquid Chromatography are excellent tools, even simple analyses help to avoid unwelcome changes in the day to day practice.     

50t上面发酵小麦啤酒中试生产工艺技术研究

小麦啤酒是以小麦麦芽为主要原料(占原料总量的40％以上)，采用上面酵母发酵酿制而成。该实验对50t上面发酵小麦啤酒进行了研究，低蛋白白皮软质小麦麦芽、优质大麦麦芽、大米、酒花的选取及合理配比是小麦啤酒风味及质量的可靠保证；双醪浸出糖化工艺操作简便，是可行的；合理调整发酵接种量、接种温度、主发酵温度及发酵罐压力等工艺参数：对改善小麦啤酒风味，提高小麦啤酒质量起到了至关重要的作用；小麦啤酒成品稳定性测试取得了满意的结果。