The Loss of Hydrophobic Polypeptides during Fermentation and Conditioning of High Gravity and Low Gravity Brewed Beer

The object of this study was to investigate the loss of hydrophobic polypeptides, which are important for foam quality and stability in finished beer. Loss of hydrophobic polypeptide due to fermenter foaming occurs during transfer of fermented wort since a gradient of hydrophobic polypeptides towards the surface is created during fermentation. Due to higher polyphenol levels in high gravity (20°Plato) wort, more hydrophobic polypeptides are lost due to cold break (cold trub) precipitation compared to low gravity (12°Plato) wort. Another important factor affecting the loss of hydrophobic polypeptides could be proteinase A activity during fermentation, especially in high gravity fermentation where the yeast is exposed the higher stress. During high gravity fermentation, where osmotic pressures are higher, ethanol levels become greater, and nitrogen‐carbohydrate ratios are lower, more proteinase A is released by the yeast. This release of proteinase A into fermenting wort could have implications for the foam stability of the finished product.     

COMMERCIAL BREWING TRIALS WITH ZENITH HOPS

Commercial brewing trials with Zenith hops from the 1982 and 1983 crops have shown that these hops are suitable for producing both ales and lager beers.     

快速酿造葡萄酒酵母的筛选

通过SO2、酒精和高酸度的耐受性实验,从22株葡萄酒酵母菌中筛选出若干株发酵能力和耐受性均较高的优良菌株,用于低档葡萄快速发酵生产。实验的极限值为:在初发酵液中,SO2的含量为250mg/L,酒精浓度为18%,pH值为2.7。经验证,用筛选株12号菌生产的红葡萄酒可以达到国家标准。     

营养型发酵软饮料的研究

研究利用稻加工大米的副产品碎米为主要原料 ,加入麦芽、加酶 ,进行液化、糖化、发酵等工艺 ,研制出一种发酵营养型软饮料。本产品与啤酒相比 ,可减少原料总用量的 17% ,减少麦芽用量的 2 8.6%。     

The value of quality clues in the wine market: evidences from Lazio,Italy

The purpose of the paper is to contribute to understanding the role and effectiveness of different quality clues in the creation of value for the main wines of the Lazio region. The study presents a hedonic price model. An ordinary least squares and a quantile regression models were estimated. The latter is able to detect additional patterns related to the effects of the covariates. Prices are regressed on wine color, sub-regional area of origin, the type of certification of origin, and on experts' evaluation. The analysis is based on data released by three major Italian wine guides: Gambero Rosso, l'Espresso, and AIS (Italian Sommelier Association). Results show that: (i) white and red wines follow two different price patterns; (ii) prices are correlated with experts' evaluation; (iii) the impact of the latter is higher when other quality clues, such as geographical indications, are less effective; (iv) the role of different quality clues varies at different price levels and it is different for red and white wines; overall, wines from the Lazio region are associated with poor to mediocre quality levels. This may explain the decline in reputation and in market share that these wines are experiencing after centuries of popularity.     

Reduced acetaldehyde production by genome shuffling of an industrial brewing yeast strain

High levels of acetaldehyde produced by yeast during fermentation can be of concern to product quality. A novel approach, based on genome shuffling, was applied to reduce the production of acetaldehyde by industrial brewing strain YS86. Four isolates with different impacts of acetaldehyde concentration were obtained from populations generated by ultraviolet irradiation and nitrosoguanidine mutagenesis. These yeast strains were then subjected to recursive pool‐wise protoplast fusion. A strain library that was likely to yield positive colonies was created by fusing the lethal protoplasts obtained from both UV irradiation and heat treatments. After two rounds of genome shuffling, a recombinant YSF2–9 strain produced less acetaldehyde than wild‐type strain YS86, by 64.5 and 66.2% in laboratory and pilot plant fermentations, respectively. The shuffled yeast strain YSF2–9 was genetically stable and may have a potential application in brewing industry for managing acetaldehyde in beer. Copyright © 2017 The Institute of Brewing & Distilling     

Brewer’s spent grain as a functional ingredient for breadsticks

Brewer’s spent grain (BSG) was evaluated for its potential as a functional baking ingredient. Scanning electron microscopy (SEM) was used to examine the microstructure of BSG and wheat flours. Baked snacks (breadsticks) were prepared using 15%, 25% and 35% BSG and evaluated for their baking quality and fibre and protein content (over a period of 3 months). The addition of BSG altered the baking characteristics of the breadsticks by affecting their structure and texture. The snacks appeared to lack in cellular structure and crispiness. However, they had quite a stable shelf‐life, as changes in texture, moisture and a_w progressed at a low rate. Addition of 25% and 35% BSG significantly increased the protein content of the snacks, and addition of 15% BSG more than doubled the content of dietary fibre in the samples.     

白酒酿造机械化新工艺设备系统的实践

介绍了白酒酿造机械化新工艺的原理、设备选型、系统配置和实例及自动化控制在其中的应用,并展望了未来应用前景。     

大豆酶解产物复合含氮糖浆用于啤酒发酵的研究

本文主要对大豆蛋白水解产物用于部分替代麦汁进行啤酒发酵的可行性进行了实验研究,并对发酵液的理化指标进行了检测分析.实验证明酵母在添加了大豆蛋白酶解液中的发酵液里可以正常发酵,所得啤酒各项指标均符合国家标准.     

浓盐法提取啤酒酵母中RNA的研究

对影响浓盐法提取啤酒酵母中RNA的条件进行了研究,确定其较优生产条件为:温度95 ℃,加盐量10 %,提取时间120 min,调等电点pH4.2沉淀蛋白质后4℃静置8 h.在此条件下,从45 g湿酵母(相当于10 g干酵母)中可提取0.5308 g RNA,蛋白质含量为0.0615%,A260/A280为1.988.