巴氏杀菌引起爆瓶的原因分析

瓶装啤酒的杀菌一般采用隧道式巴氏杀菌机。在杀菌温度65℃以下、CO2质量分数0．4％～0．5％时，瓶装啤酒的瓶颈部分体积为瓶总容积的3％。杀菌温度在65℃以上时为4％，除此之外，诸多原因会使杀菌时瓶内压力过高而造成爆瓶。     

桶装啤酒瞬时杀菌机的工艺控制

原始的鲜啤因酵母等微生物的存在，保质期太短，造成经营上的困难，因而难以推广。我厂从德国GEAAHIBORN公司引进了板式瞬时杀菌机，采用先进瞬时杀菌再装桶的方法，取得了良好的效果、生产出的眸酒基本上保持了鲜啤酒原有的风味。一般瓶装啤酒采用的隧道式喷淋杀菌方式杀菌，设备占地面积大，设备和生产费用高，特别是杀菌时间长一难以保持啤酒原有的风味，而AHIBOR周公司的杀菌机采用薄板瞬时已氏杀菌月很短的时间，很低的能耗达到应有的杀菌效果，同时保证了鲜啤的风味。他们在杀菌工艺的控制方面作出了许多可贵的探索，值得我们…     

瓶装啤酒隧道式巴氏杀菌的数值模拟

为了保证啤酒的生物稳定性,需要对其进行巴氏杀菌。通过数值模拟瓶装啤酒隧道式巴氏杀菌的过热阶段,考察瓶内冷核(slowest heating zone,SHZ)的位置,分析在不同温度喷淋水条件下瓶内温度分布均匀情况。结果表明:在巴氏杀菌过程中,瓶中啤酒冷核位于1/3灌装高度;瓶内有明显的自然对流现象;当喷淋水温度为61℃时瓶中啤酒温度分布最为均匀,且温度越高瓶内啤酒温度分布越不均匀。     

啤酒生产过程中影响泡沫性能的因素分析

泡沫性能是反映啤酒质量的重要指标。虽然影响啤酒泡沫性能的因素很多。最重要的因素是疏水多肽的存在。酵母在发酵过程中会产生蛋白酶A，死亡酵母也会分泌蛋白酶A，蛋白酶A能降低疏水多肽的含量从而对啤酒泡沫不利。这种影响随着啤酒保存时间的延长会更加明显。高浓度的麦汁发酵对啤酒泡沫不利，巴氏杀菌对蛋白酶A的活力以及啤酒泡沫稳定性有影响。本研究中进行了两套类似全麦芽酿造的实验，其中一种经过隧道式杀菌机杀茼，另一种则经过膜过滤不进行巴氏杀菌，检测三个月保存期内两种啤酒的泡沫性能、蛋白酶A活力及疏水多肽含量。结果发现巴氏杀菌的啤酒中蛋白酶A活力下降，未进行巴氏杀菌的啤酒此酶活力很高，后者中疏水多肽含量下降是由于受蛋白酶分解所致；经过巴氏杀菌的啤酒即使保存一段时间后其泡持性依然很好，而未经巴氏杀菌的啤酒泡持性下降。离心会影响蛋白酶A的活力，因为在离心过程中产生的剪切力和热量会破坏酵母细胞的完整性。剪切力增加了死亡酵母的数量，导致更多的细胞内容物释放，其中包括蛋白酶A。     

微生物与杀菌机PU值控制

巴氏杀菌作为瓶装熟啤酒的必经工序，其作用是使啤酒获得生物稳定性，在保质期内不发生微生物混浊。巴氏杀菌必须在最短时间内以适当的温度杀灭啤酒中可能存在的微生物，过度杀菌会影响啤酒的风味和口感，根据企业的实际情况，研究微生物与杀菌机PU值的控制问题十分必要。     

二氧化氯在啤酒保鲜中的应用

在中小型啤酒企业的扎啤酒生产中，由于资金和条件有限，一般都不具备自动洗刷灌装和瞬时杀菌条件，大大的影响了扎啤酒的保鲜期，特别是在炎热的夏季，由于气温高，扎啤的保鲜问题更为突出，在扎啤中添加二氧化氯可有效的提高保鲜期，而且口味不受影响。     

纯生啤酒的无菌生产技术

纯生啤酒是啤酒行业中的高科技产品,其关键技术是以低温膜过滤除菌代替传统的巴氏杀菌,这项技术对啤酒生产过程的所有环节提出了更高的无菌的要求。本文以低温膜过滤除菌技术为重点介绍了纯生啤酒无菌生产的各技术要点。     

纯生啤酒的无菌生产技术

纯生啤酒是啤酒行业中的高科技产品,其关键技术是以低温膜过滤除菌代替传统的巴氏杀菌,这项技术对啤酒生产过程的所有环节提出了更高的无菌的要求。本文以低温膜过滤除菌变重点介绍了纯生啤酒无菌生产的各技术要点。     

浅谈高温瞬时杀菌生产瓶装啤酒的技术

本文中笔者谈谈本公司采用瞬时杀菌技术生产瓶装啤酒的一些经验，供同行参考。     

巴氏杀菌中的几个问题

瓶装、听装熟啤酒巴氏杀菌是灌装车间的重要工序,杀菌效果直接影响成品啤酒质量。 1.杀菌强度的选择杀菌强度用巴氏杀菌单位Pu来表示,它和时间成正比,和温度成指数关系: 杀菌强度=时间×1.393~(t-60) 一定的杀菌强度是成品啤酒生物稳定性的保     

A preliminary study of the quality attributes of a cloudy wheat beer treated by flash pasteurization

Flash pasteurization (37 and 100 pasteurization units, PU) and conventional tunnel pasteurization (15 PU) processing of wheat beers were evaluated by examining their impacts on microorganisms, colour, colloidal haze and flavour stability during 84 days of storage at 20°C. The results revealed that the microbiological stability of 37 and 100 PU flash‐pasteurized beers was comparable with that of the 15 PU sample, and the development of both yeast and lactic acid bacteria was inhibited for 84 days of storage. The conventional tunnel‐pasteurized wheat beer resulted in a higher thermal load relative to the flash‐pasteurized samples based on the results of oxidative stability. These three pasteurized beers showed a similar decrease in haze intensity throughout the storage period. Meanwhile, flash‐pasteurized beers had better colour and colloidal haze stability than the tunnel‐pasteurized beer. It was also found by dynamic light scattering analysis that the temperature in the flash pasteurizer has the desired effect on the protein denaturation and particle size distribution. Therefore, flash pasteurization is a promising method to increase the shelf‐life of wheat beers instead of conventional tunnel pasteurization. Copyright © 2017 The Institute of Brewing & Distilling     

The Biological Impact of Flash Pasteurization Over a Wide Temperature Interval*

Trials on the impact of flash pasteurization on beer quality showed that higher pasteurization temperatures with shorter holding times are favourable for beer quality. However, the killing effect in the temperature range up to 90°C has not been elucidated so far. Pasteurization temperatures of 50°; 60°; 72°; 84° and 90°C and pasteurization units of 0; 15; 80 and 500 PU were used. The associated residence times were calculated according to Del Vecchio et al.'s formula. The experiments with beer‐relevant yeasts and bacteria showed that Saccharomyces yeasts are much easier to inactivate than Lactobacilli and Pediococci. Furthermore, it can be stated that the commonly used PU calculation according to Del Vecchio reflects the actual killing characteristics in the temperature range from 60° to 72°C quite precisely. Although flash pasteurization with low PU figures at temperatures higher than 72°C and with very high amounts of bacteria may be insufficient, because the real inactivation effect is lower than indicated, there is no need to increase the PU load when changing to higher pasteurization temperatures and shorter holding times in practical application.     

Computational study for microwave pasteurization of beer and hypothetical continuous flow system design

Beer pasteurization is carried out in conventional systems where low temperature and long time process (56 min process with 13 min pre-heating, 14 min heating, 6 min holding time and 23 min cooling time) is applied for bottled or canned products. Longer process times lead to losses in the sensory properties. Another approach is flash pasteurization where the beer is first pasteurized and then filled into bottles or cans. For flash pasteurization, microwave (MW) process with rapid heating feature might be an innovative alternative. Therefore, the objective of this study was to explore the MW processing for beer pasteurization. For this purpose, a computational mathematical model was developed to determine the temperature change of beer during MW process and experimentally validated in a 2450 MHz lab-scale system. Following the validation, process design studies for a continuous flow system were carried out. These studies demonstrated the MW application as a rapid process (e.g. 60 s of total MW heating time at 5000 W with a short holding time of 27 s) to achieve the required pasteurization unit at a flow rate of 50.4 kg/h. This confirmed the MW process as a possible industrial application. Using these results, continuous flow process optimization studies for industrial process considerations might be planned.     

Free radical reactions in beer during pasteurization

Oxidative reactions during beer pasterization were studied using chemiluminescence (CL) and electron spin resonance (ESR) analyses. the CL production of beer was acclerated by pasteurization and the maximum CL intensity appeared sooner than that in non-pasteurized beer. Beers pasteurized with 15–30 pasteurization units (P.U) had the same CL producing activities as the non-pasteurized beers stored at 20°C for 6–10 days. Free radicals were produced and some of them were consumed by beer oxidation during pasteurization. It seems that free radicals were consumed by beer oxidation during pasteurization. It seems that free radical reactions occur in beer during pasteurization and that the degree of oxidation during pasteurization generally corresponded to that of non-pasteurized beer stored at room temperature for about 1 wee.     

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.     

鲜啤和白糯米酒脉冲强光冷杀菌技术初探

采用脉冲强光冷杀菌技术分别对鲜啤酒和白糯米酒进行杀菌处理,研究了脉冲强光对鲜啤酒和白糯米酒杀菌效果的影响。结果表明:鲜啤酒经过频率为5次/s闪照处理3min后,酵母菌在啤酒中的含量从220cfu/mL降至175cfu/mL,0℃下啤酒保质期延长3d。白糯米酒经过频率为4次/s闪照处理3min后,酵母菌在白糯米酒中含量从235cfu/mL降至5cfu/mL,在0、10、20、35℃下白糯米酒的保质期分别延长50、30、6、2d。同时通过感官评定和电子鼻检测,发现在上述冷杀菌条件下处理后的鲜啤酒和白糯米酒风味无显著变化。     

Storage stability of pasteurized non‐filtered beer

The influence of pasteurization on non‐filtered beers was investigated during accelerated storage (40°C, 41 days). Two beers were produced from the same hopped wort, which was fermented with two different yeast strains. Half of the bottled beers were tunnel pasteurized resulting in four different beer samples. The pasteurization influenced the volatile profile of both fresh beers, but during storage the differences between the volatile profiles of pasteurized and non‐pasteurized beers disappeared. During the storage period, the pasteurized beers gave a lower rate of radical formation, as evaluated by electron spin resonance spectroscopy, indicating a better oxidative stability. The pasteurization had no effect on the levels of the pro‐oxidative metals iron and copper. Pasteurization slightly increased the protein content of the beers. SDS–PAGE analysis showed that the two beers had different protein profiles, which changed during storage; however, pasteurization of both beers did not affect their protein profiles. The level of thiols were lowered in one beer and raised in the other beer by pasteurization, but during storage the levels of thiols decreased at the same rate in all of the beers. It was concluded that pasteurization had a positive influence on the oxidative stability of non‐filtered beer. Copyright © 2013 The Institute of Brewing & Distilling     

Effect of high hydrostatic pressure on quality parameters of lager beer

Unpasteurized lager beer samples from a commercial brewery were treated either by high hydrostatic pressure (HHP; 200, 250, 300, 350 MPa for 3 and 5 min at 20 °C) or by conventional heat pasteurization (60 °C for 15 min). The main attributes of the beer, such as ethanol content, extract and pH, were not affected by either treatment; however HHP and heat pasteurization affected colour, chill haze, protein sensitivity and bitterness. Change in bitterness was higher in conventional heat pasteurization, but pressures up to 300 MPa had no significant affect on bitterness. 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 process beer, even at temperatures well below those required for heat pasteurization, without affecting some of the quality attributes. Copyright © 2005 Society of Chemical Industry     

Effects of High Pressure Homogenization on Beer Quality Attributes

The aim of the present study was to evaluate the use of high pressure homogenization (HPH) as an alternative to thermal pasteurization for beer stabilization and to evaluate the effect of processing on colour, haze and redox potential immediately after the process and during the product shelf‐life (100 days). The results obtained showed good colour retention, changes in the redox potential and greater values for turbidity, presenting a higher value for the product treated by HPH than for the thermally treated samples reported in literature. The evaluation of the results indicated that the HPH process is a promising process for beer treatment in terms of guaranteeing better colour retention. However to make this product stable, it would be necessary to perform stabilization treatments to minimize the negative effects of processing on the haze of the final product.     

延长鲜豆浆(豆乳)保质期的研究

豆浆(豆乳)保鲜一直是大豆业界的技术难题。为了保证豆浆(豆乳)良好的风味和常温下贮存的安全性，文中探讨了几种不同性能的食品防腐剂和巴氏杀菌工艺对延长豆浆(豆乳)保质期的可能性。试验证明，有少数防腐剂对豆浆(豆乳)具有较好的抑菌作用，可以适当延长产品的保质期，其中保鲜剂E可使巴氏杀菌的鲜豆浆(豆乳)产品在≤25℃条件下，保质期达到3d，37℃下保存1d。