气相色谱法在啤酒分析中的应用

采用气相色谱法可对啤酒中的高级醇、酯类、羰基化合物及含硫化合物等挥发性物质进行检测,既可研究啤酒的感官品质,也可用于指导生产,优化啤酒工艺。应用气相色谱法对啤酒中挥发性物质检测的前处理方法主要有顶空进样、蒸馏、有机溶剂萃取3种。针对啤酒酒中不同的挥发性物质可选择PEG柱和氢火焰离子化检测器（FID）法进行检测;还可用内标法和外标法对啤酒中的不挥发组分进行定量检测分析。（孙悟）     

控制发酵度、稳定啤酒风格

随着消费结构和消费群体的变化，以及消费者的消费意识和消费品位的不断提高，对啤酒的典型性、产品的风格要求也越高。可通过控制啤酒的发酵度，改善和提高啤酒的口感、风味的稳定性，提高产品的质量；重要措施有：对酵母菌株进行选育、驯化和纯化；调整合适的糖化生产工艺和发酵工艺，有效控制通氧量、发酵温度、酵母接种量及各项发酵条件，控制啤酒高级醇含量，掌握啤酒与氧含量之间的关系；定期组织品评人员对啤酒进行品评，遵循PDCA循环的原则等。     

啤酒蒸馏酒成分变化规律研究

采用直火式蒸馏塔对市售工业啤酒和三种精酿啤酒(IPA、比利时小麦啤酒、Stout黑啤)分别进行了蒸馏试验。对酒精度、出酒量、成分变化进行了分析。结果表明,酒精度在2~4min内迅速升高,最后下降到20%左右不再出酒。出酒量在15min时达到最大值,然后逐渐减少。直火式蒸馏塔对风味物质保留有较好效果,三种精酿啤酒蒸馏产物中的芳香物质损失少于市售工业啤酒。     

Pilot‐scale brewing using self‐cloning bottom‐fermenting yeast with high SSU1 expression

A pilot‐scale fermentation was performed using SSU1‐overexpressing bottom‐fermenting yeast strains constructed by ‘self‐cloning’. In these strains, the gene SSU1, encoding a plasma membrane protein that excretes sulphite, was highly expressed. The rate of fermentation of the two SSU1‐overexpressing strains tested showed some reduction during the mid‐fermentation phase as compared with the parental strain. These differences, however, did not affect overall fermentation and the final apparent extracts had decreased to a level normally obtained during brewing. The concentration of hydrogen sulphide in the wort remained low during fermentation in the case of the two self‐cloning strains compared with the parent. The concentration of 2‐mercapto‐3‐methyl‐1‐butanol, a sulphur compound that causes an ‘onion‐like’ off‐flavour, was also reduced in the case of the self‐cloning strains, a result confirmed by sensory evaluation of the beer immediately after bottling. Furthermore, with these strains the anti‐oxidation potential of bottled beer, as measured by electron spin resonance, was improved and the concentration of trans‐2‐nonenal in bottled beer after 7 days of accelerated aging at 37°C was decreased. These observations, together with the lower stale flavour score determined by sensory evaluation of bottled beer after a month of aging at 25°C, indicated that the flavour stability of the beer had been successfully improved. Copyright © 2013 The Institute of Brewing & Distilling     

Simulation of vacuum distillation to produce alcohol-free beer

Several processes have been developed for producing alcohol-free beer while maintaining desirable sensory characteristics. One of the most popular thermal processes used is distillation, where not only ethanol but volatile aromatic components are partly or completely removed from the beer. Based on data from the literature and using the Aspen Plus simulator, this study evaluates and compares the aroma profiles of alcohol-free beers obtained by continuous vacuum distillation with different pressures and processes. Three processes were simulated at pressures of 60, 102, and 200 mbar. The first (Process A) was a standard continuous vacuum distillation, where the bottom product was an alcohol-free beer. In the second (Process B), the bottom product was blended with a standard beer that had not undergone any thermal process. In the third (Process C), part of the top stream was mixed with the bottom product. This study considered eight major compounds in beer: ethanol, propanol, isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol, ethyl acetate, diacetyl and isoamyl acetate. The three simulated pressure ranges showed similar results, indicating that reducing the pressure below 200 mbar did not improve separation. Further, vacuum distillation did not remove diacetyl from the beer. Processes B and C resulted in beer that was richer in flavour compounds. Furthermore, when these processes were compared to Process A, the concentration of esters was markedly higher. © 2019 The Institute of Brewing & Distilling     

无酒精啤酒的研究

<正> 无酒精啤酒是一种酒精度低于1 w/w％的饮料,它具有啤酒的色、香、味。因其酒精度低特别适于司机、运动员、孕妇、儿童及老年人饮用。无酒精啤酒的生产方法已有许多,但各自又存在着一定的问题,本论文的目在: 1.选出控制或除去酒精的有效方法。 2.以气相色谱法测定风味物质,对产品的风味进行改善。     

Factors influencing proteinase A activity during the production of unpasteurised beer

Compared with pasteurised beer, a decline in foam retention during storage is an issue for unpasteurised beer. The major reason for this is that proteinase A is able to slowly breakdown foam promoting proteins in beer. Therefore, controlling the activity of proteinase A is key to solving this problem. In this study, foam quality in unpasteurised beer was studied systematically on a commercial scale considering factors including yeast activity, strain, generation number and storage time. Accordingly, yeast handling procedures to manage proteinase A activity were established: (1) yeast strain P with reduced proteinase A should be used in production; (2) storage time of recovered yeast should be no more than two days; (3) proteinase A activity in recycled yeast slurry should be less than 10×10^‐5 U/mL and (4) the number of yeast generations should be less than three. With the application of these measures, proteinase A activity was significantly decreased, and the corresponding foam quality was improved. © 2020 The Institute of Brewing & Distilling     

阿尔特啤酒生产工艺的研究

介绍使用上面发酵酵母、下面发酵酵母和特种麦芽生产阿尔特啤酒的工艺技术,生产工艺的研究为阿尔特啤酒的开发提供了可行的工艺参数。     

啤酒酵母的分离与性能检测

介绍了啤酒酵母的优化、筛选、培养工作的方法和步骤。     

微型啤酒的酿造与酵母扩培技术

在微型啤酒设备中,一般不设计酵母扩培罐,所用酵母以外购为主,接种酵母的优劣就成了啤酒质量的关键。介绍了一种简捷方便、自主进行酵母逐级扩大培养的实用技术,争取做到酵母自备自用。同时,选用优质原料,采用科学合理的糖化、发酵工艺,确保酿制出优质的鲜啤酒,以满足广大消费者的需要。     

啤酒酵母抽提物工业化生产

据统计，每生产1t啤酒就有1.5kg啤酒废酵母（干）产生，一个年产10万t的啤酒企业可产生150t啤酒废酵母，可实现工业化生产。经过多次工业试验，酵母抽提物得率可达70％。生产工艺为酵母泥经除杂、压榨取酒、水洗脱苦、调浆、自溶（酶解）、灭酶、过滤、滤液浓缩、调配而得成品。生产10万t的啤酒企业，其啤酒酵母用于生产酵母抽提物，可创造效益近200万元。同时，还产生明显的社会效益和环保效益。（庞晓）     

“SP-3”与“SP-2”在全小麦啤酒酿造中应用研究

“SP-3”是新选育的啤酒酵母菌株,而“SP-2”为通常生产大麦芽啤酒使用的啤酒酵母菌株,“SP-3”与“SP-2”啤酒酵母菌株在全小麦啤酒生产中应用对比试验结果表明,“SP-3”啤酒酵母菌株在全小麦芽啤酒的酿造中适用性较强,各项指标均优于“SP-2”啤酒酵母菌株,用其酿制的啤酒口感纯正、清爽、柔和,能够较好地适应当前消费者的口感需求.     

Optimization of alcohol‐free beer production by lager and cachaça yeast strains using response surface methodology

Alcohol‐free beers (AFBs) are an attractive segment of the beer market both for the brewing industry and for consumers. While AFBs produced by arrested/limited fermentation often suffer from a lack of volatile compounds, beer flavour can be improved by yeast selection and optimization of fermentation conditions. The yeast selection strategy was demonstrated by comparing traditional lager yeast with selected cachaça yeast strains. Correspondingly, response surface methodology was used to enhance the formation of the flavour‐active volatile compounds by optimization of the fermentation conditions (original wort extract, fermentation temperature, pitching rate). Statistical analysis of the experimental data revealed the relative significance of process variables and their interactions. The developed quadratic model describing the responses of total esters and higher alcohols to changes in process variables was used to predict the ideal fermentation conditions in terms of flavour formation. The predicted conditions were experimentally verified and alternative strategies of AFB production are suggested. Copyright © 2016 The Institute of Brewing & Distilling     

国内啤酒废酵母生产酵母味素的困惑及思考

国内对酵母味素的研究和开发始于20世纪80年代，随国产食用酵母行业的发展，酵母味素的生产得以发展，又酵母味素的市场也得到发展，但受啤酒酵母味素行业不景气的影响。困扰国内啤酒酵母味素生产的因素有：脱苦、脱色困难；原材料得不到保征；啤酒酵母味素风味欠佳；酵母味素抽提单低；生产操作难度大。投资啤酒酵母味素必须考虑啤酒行业的格局变化；生产技术、生产工艺有待进一步完善和提高；啤酒酵母味素的生产线最好建在啤酒企业内部；啤酒废酵母的综合开发都是行业内存在的问题。(孙悟)     

控制啤酒中高级醇含量的研究

研究和分析了啤酒中高级醇的生成和控制措施,主要通过改良酿酒酵母、优化发酵工艺和培养基组成等措施来降低啤酒中的高级醇,达到提高啤酒质量和降低生产成本的目的。     

青岛啤酒酵母与高浓酵母筛选高浓酿造酵母融合亲株

以青岛啤酒酵母和高浓精酵母为供试菌株,筛选出生长良好的酵母,为选育具有青岛啤酒风味的高浓酵母做准备.比较了7株酵母不同糖类发酵、离子抗性、二氧化碳减重、发酵液风味品评等指标.结果表明:T1、T2和T3是传统的青岛啤酒发酵菌株,其发酵液口味符合青岛啤酒口味要求,且对Cu2+均不耐受;而G4和G6发酵减重试验和风味物质分析中的乙醛含量指标的评价均优于G5和G7菌株,且它们的发酵液的风味也接近青啤口味.因此,选择T1、T2、T3和G4、G6作100L酿造试验,进一步确定融合亲株.     

A novel approach for the production of a non‐alcohol beer (≤0.5% abv) by a combination of limited fermentation and vacuum distillation

Despite the increasing demand, the production of non‐alcohol beers is still limited by unsatisfactory or artificial flavour and taste. In this study, a novel approach to producing non‐alcohol beer is presented, in which the alcohol‐reducing techniques, limited fermentation and vacuum distillation were combined. Starting from barley and wheat malts, wort with a low level of fermentable sugars was prepared by infusion mashing and lautering. Limited fermentation was carried out by Saccharomycodes ludwigii at 18°C. When the level of fermentable sugar was reduced by 25%, the fermented wort was quickly cooled from 18 to 0°C and held at that temperature for two days. The young beer was obtained after degassing and removal of yeast and was then subjected to vacuum distillation at 0.06 MPa to remove the alcohol. The concentrated extract is suitable for storage and transportation. The final product of non‐alcohol beer was obtained by dilution with deoxygenated water and carbonation with 6.0 g/L CO₂, followed by addition of 8–12% of regular beer and equilibration for 2–3 days to develop normal beer aroma. The results showed that the non‐alcohol beer had several favourable properties, including the alcohol level of <0.5% (v /v), colour 7.0 (EBC), thiobarbituric acid value of 1.05 and ratio of alcohols to esters of 1.08. Compared with other methods for the production of non‐alcohol beer, this novel approach produced a favourable alternative to regular beers with similar flavour characteristics and satisfactory stability. Copyright © 2017 The Institute of Brewing & Distilling     

啤酒酵母扩大培养的研究

啤酒酵母的好坏直接影响啤酒的质量，而啤酒酵母的扩大培养又是微生物工作的核心，本文从酵母茵株的选择等几个方面研究了啤酒酵母扩大培养的关键所在，从而保证啤酒的质量。     

啤酒酵母富集锌的工艺研究

啤酒酵母生长周期短,对微量元素吸收率高,是可以将金属离子由无机态转化为有机态的理想载体。应用啤酒酵母将无机锌转化为有机锌,可以作为锌补充制剂,从而改善生物体对无机锌吸收利用难,避免出现肠胃不适甚而胃出血的现象,达到促进智力发育、增强免疫力等功效。研究了啤酒酵母富锌的最适培养条件。     

氮酮促进啤酒废酵母蛋白质释放的研究

目的：研究啤酒酵母菌的破壁技术。方法：利用氮酮对生物膜类脂具有特异性溶解作用，使酵母菌细胞内膜类脂流动性增强，促进酵母菌体内蛋白质释放。结果：发现氮酮除了可以作为药物的透皮吸收促进剂外，还有促进酵母菌体内蛋白质释放的作用。结论：氮酮可使啤酒酵母菌蛋白质释放率达湿重的4％。