浅谈几种啤酒非生物混浊和沉淀

本文结合工作实际经验,谈谈影响啤酒非生物稳定性引起的混浊如下:1.蛋白质混浊啤酒中的蛋白质混浊可分为热冷混浊、灭菌混浊、氧化混浊、铁-蛋白质混浊。1.1 热冷混浊:热冷混浊通常为“可逆混浊”。热混浊主要是热麦汁在沉降过程中静置时间不够,使热凝固物残留于啤酒中。冷混浊主要是β-球蛋白和δ-醇溶蛋白,当啤酒受冷时,这些蛋白质与多酚结合形成多酚—蛋白质复合体,使啤酒失光,而当温度升温时,恢复啤酒光泽。1.2 灭菌混浊:因啤酒中溶解的蛋门质分子量较大,M>60000以上。在 pH 值较低、温度大于     

啤酒蛋白质混浊的成因及工艺措施

在啤酒非生物混浊中,90%以上是蛋白质混浊。引起蛋白质混浊的主要因素:高分子蛋白质、多酚物质、氧。它们主要来源于麦芽、酒花以及工艺过程。蛋白质混浊分为:真正蛋白质混浊、冷混浊、永久混浊。一、啤酒蛋白质混浊的成因1.真正蛋白质混浊瓶装啤酒在杀菌后出现片状絮状物,它实际上是成品啤酒中含有多量的热凝固蛋白。是由于麦芽溶解差、糖化时蛋白分解不     

啤酒中的混浊活性蛋白质

1前言啤酒的成分复杂,稳定性不强,易产生混浊沉淀。最常见的啤酒非生物混浊是蛋白质混浊。形成蛋白质混浊的原因在于啤酒中有两种主要成分,即蛋白质和多酚物质。在啤酒中,某些多酚物质("混浊活性多酚")可以与蛋白质("混浊活性蛋白")结合形成复杂的复合物,且二者存在一定     

啤酒非生物稳定性及控制

在啤酒市场由卖方市场转变为买方市场后 ,啤酒生产和市场竞争日趋激烈 ,生产企业要在竞争中立于不败之地 ,首要是提高啤酒质量 ,增强啤酒的稳定性。啤酒中含有多种氨基酸 ,营养非常丰富。这些物质在氧、光照、震荡及保存时会发生一系列变化 ,啤酒的胶体稳定性被破坏 ,出现不同程度、不同形式的混浊现象 ,严重影响啤酒的质量。1　影响啤酒非生物稳定性的因素影响啤酒非生物稳定性的主要因素是啤酒中的高分子蛋白质、多酚物质 ,糊精及重金属离子。常见的非生物混浊主要是蛋白质混浊及其它情况引起的混浊。1 1　蛋白多酚混浊主要有以下几种情…     

啤酒多酚-蛋白质沉淀及低温酒精冷混浊预测啤酒保质期

啤酒的混浊问题比较复杂，但通常是由多酚—蛋白的复合物引起的非生物混浊；低温酒精冷混浊试验可以快速地预测啤酒保质期，该法简捷，测定结果预见性强，填补国内无快速预测啤酒保质期的技术空白。     

酚类物质和硅胶对啤酒中敏感蛋白的吸附选择性研究

啤酒中的混浊活性蛋白（敏感蛋白）富含脯氨酸。对0℃、37℃以及室温下分离的啤酒混浊物质进行氨基酸分析后发现，不同贮藏温度条件下产生的混浊物质中脯氨酸含量差异很大，依次为13．22％，11．30％和10．44％（均为摩尔百分含量），原因是不同贮藏温度下啤酒中的多酚物质氧化聚合情况不同，造成其对敏感蛋白的选择性差异；0℃贮藏条件下，多酚物质对敏感蛋白选择性最高，37℃次之，室温保藏最差：对硅胶吸附的蛋白质进行氨基酸分析后发现，硅胶吸附蛋白质的脯氨酸含量比啤酒总蛋白所含脯氨酸要高出许多，说明硅胶对敏感蛋白有一定的选择性吸附，且不同硅胶产品对敏感蛋白的吸附选择性也有差异，可以把硅胶吸附蛋白质的脯氨酸含量作为评价硅胶产品质量的一个参考性指标。     

脯氨酸内切酶对提高啤酒非生物稳定性的研究

啤酒中含有脯氨酸的敏感蛋白质易与敏感多酚形成混浊聚合物.控制啤酒麦汁或发酵液中含脯氨酸的敏感蛋白含量是有效控制啤酒非生物稳定性的重要因素.分析脯氨酸特效内切酶Brewers Clarex在发酵过程中对易形成非生物混浊的相关指标的影响,研究其提高啤酒非生物稳定性的性能.实验证明,Brewers Clarex提高啤酒非生物稳定性的效果显著,不影响啤酒的风味物质,对酵母性能及酿造过程成熟度指标均没有影响.     

由多酚、蛋白质引起啤酒非生物混浊的研究

啤酒是一种成分复杂，稳定性不强的胶体溶液，有很多因素会导致啤酒混浊，但啤酒混浊物的主要成分是多酚、蛋白质所引起的。本文主要探讨了多酚、蛋白质由于分子间的亲和性不同而形成啤酒混浊复合物的原理以及由活性蛋白、活性多酚之间相互作用的结合机制；最后还讨论了由多酚和蛋白质形成混浊物的动态无差异曲线图，从而从分子的角度对啤酒混浊物形成机制得到进一步的阐述，并且就如何提高啤酒非生物稳定性提供了解决思路。     

脯氨酸特效内切蛋白酶的酿造适用性研究

啤酒混浊主要由混浊敏感蛋白和多酚相互作用而形成。脯氨酸特效内切蛋白酶是由黑曲霉发酵产生的一种脯氨酸专一性内切酶,能水解混浊敏感蛋白的脯氨酸而使其“失活”。通过对发酵过程主要指标的跟踪及最终发酵液质量评价,研究了该酶对啤酒酿造性能的影响;通过对不同过滤条件下（PVPP和硅胶）啤酒的非生物稳定性及抗冻性的综合比对,研究了该酶对啤酒非生物稳定性的影响。研究发现使用脯氨酸内切酶能在不影响发酵性能的前提下显著提高啤酒的非生物稳定性。     

标准曲线法测混浊活性蛋白初探

多酚蛋白复合引起的混浊现象是啤酒,果汁需要着重解决的问题之一。本文探讨了标准曲线法测定啤酒,果汁中混浊活性蛋白的可行性。结果表明,PVP的浓度在0.000～0.100g/L范围时,反应产物的浑浊度与PVP浓度成良好的线性关系。     

啤酒中浑浊敏感蛋白的分离与鉴定

啤酒非生物稳定性是影响啤酒质量的重要指标之一,非生物浑浊主要是啤酒中的浑浊蛋白质与多酚结合体组成的,浑浊敏感蛋白质主要来自大麦醇溶蛋白,是一种富含脯氨酸的蛋白质.主要阐述了浑浊敏感蛋白质的分离,以及利用蛋白免疫印迹法(Immunobloting)鉴定啤酒中的浑浊敏感蛋白质,此外还研究了硅胶对啤酒的浑浊蛋白质的影响.     

Haze formation in beverages

The most frequent cause of hazes in beverages is due to protein-polyphenol interaction. Proteins that bind polyphenols contain proline, and the more proline, the greater the haze-forming activity. Polyphenols that cause haze have at least two sites that can bind to proteins; this enables them to cross-link proteins together and results in insoluble particles that scatter light. Protein-polyphenol interaction is non-covalent and, at least initially, reversible. The size of haze particles and the haze intensity are both affected by the ratio of haze-active (HA) polyphenol to HA protein. Alcohol content and pH also exert strong influences. Particle size in a model system does not vary smoothly as conditions change; rather shifts in the proportions of particles of a few discrete sizes are seen. Haze development occurs over time in packaged products. In clear beverages a treatment (fining, adsorption or ultrafiltration) is normally applied to reduce the concentration of either HA protein or HA polyphenol in order to delay the onset of haze formation beyond the intended product shelf life. A nephelometer observation gives a good indication of the amount of haze people can perceive.     

啤酒的非生物混浊和稳定化处理

该文介绍了啤酒形成非生物混浊和沉淀的机理，混浊活性蛋白质和混浊活性多酚相互作用的模式。文中还对啤酒中添加吸附剂、澄清剂和蛋白酶等稳定化处理方法的作用机理进行了探讨，比较了几种稳定化处理物质的特点。     

饮料中的多酚-蛋白质反应及其稳定化处理

多酚-蛋白质反应是啤酒、葡萄酒和果汁等饮料中产生混浊沉淀的原因,限制了饮料的货架期。本文阐述了混浊反应的机理、影响因素及其稳定化处理。     

Analysis of total polyphenols,bitterness and haze in pale and dark lager beers produced under different mashing and boiling conditions

Malting and brewing processes should be performed under process conditions in a way that minimizes beer bitterness, maximizes polyphenol content and reduces the amount of raw materials ending up in solution in the form of hazes, particles and precipitates. This work examined the influence of different mashing temperature conditions and boiling procedures on the total polyphenol content, bitterness and haze of pale and dark lager beers produced on an industrial scale. Two hop types (hop pellets and/or hop extract) and different hop varieties (Hallertau Magnum, Styrian Goldings, Saaz, Aurora and Sladek) were utilized with varying times of hop addition into the wort. Measurements of total polyphenols, colour, bitterness, alcohol content, CO₂ and pH were carried out on the beer samples. Results showed that pale lager beers had a lower total polyphenol concentration (110–179 mg/L) than dark beers (230–260 mg/L). Using hop extracts instead of hop pellets led to a lower total polyphenol concentration and to less beer foam creation. The change in the proteolytic temperature during mashing only had an influence on the total polyphenol content in the pale lager beer hopped with the pellets. Conducting proteolysis over a 20 min period led to a haze increase in all of the beers produced. In the dark beer, the haze was substantial after just 10 min at 52°C. Copyright © 2015 The Institute of Brewing & Distilling     

单宁酸与麦胶蛋白结合反应的研究

以单宁酸和麦胶蛋白分别作为引起啤酒浑浊的敏感多盼和敏感蛋白的模型物质，用分光光度法对影响单宁酸与麦胶蛋白结合反应的因素进行了研究。发现，麦胶蛋白的浓度影响单宁酸与麦胶蛋白结合的方式，也影响二者的结合比例。反应温度越低、反应时间越长，单宁酸与麦胶蛋白结合反应越完全。在很低的pH值时，单宁酸与麦胶蛋白结合能力很差，在pH4．0附近，单宁酸与麦胶蛋白结合反应较完全。低乙醇浓度下，随着乙醇浓度的上升，单宁酸与麦胶蛋白结合反应程度有所下降，而在较高乙醇浓度下却随之增大。     

The chemical components in malt associated with haze formation in beer

In bright beer, haze formation is a serious quality problem, which reduces beer storage and shelf life. In this study, haze‐active proteins, alcohol chill haze formation ability, α‐amylase activity, the contents of total polyphenol, protein and its fractions and amino acids were analysed using 23 barley accessions to investigate the relationship between the quality components in the malt and the haze character in beer. The results showed that there were largely genotypic variations for all examined traits among the 23 barley accessions. However, there was no significant correlation between the haze character and α‐amylase activity. All haze characteristics were significantly and positively correlated with total protein content, albumin, globulin and the hordein content, as well as the glutamic acid (glutamine), proline and phenylalanine content, and were not correlated with total polyphenols. A model describing the relationship between the chill haze in the beer and the protein content in the malt was developed. Copyright © 2016 The Institute of Brewing & Distilling     

A Discussion of Polyphenols in Beer Physical and Flavour Stability

Generally referred to as polyphenols (PPs), beer flavonoids such as the flavan‐3‐ols and their condensed products, the proantho‐cyanidins, represent a class of readily oxidizable compounds capable of hindering or preventing the oxidation of other molecules present in beer. Flavan‐3‐ol and proanthocyanidin capacity to improve oxidative stability has been well established in other food systems, and thus these antioxidants have recently gained significant consideration as potential beer flavour modifiers and/or stabilizers. The duality of their presence in beer is that PPs complex with proteins in the beer matrix to form temporary and permanent hazes. Undesirable physical instability caused by PP‐protein interactions can be resolved via use of adsorptive resins such as polyvinylpyrrolidine. While there is no doubt that polyphenol removal increases beer shelf stability in terms of haze formation, the impact of polyphenol removal on beer flavour remains unresolved. This review discusses the sources, content and impact of polyphenol presence and removal on beer physical and flavour stability.     

TANNING PROPERTIES OF FLAVANOLS IN BARLEY AND HOPS MEASURED BY REACTION WITH CINCHONINE SULPHATE IN RELATION TO HAZE FORMATION IN BEER

The flavanoid polyphenol extracts from barley and hops were each separated into six fractions by adsorption chromatography on Sephadex LH20. These fractions were further characterised by several analytical methods, including high-performance liquid chromatography and a colorimetric measurement of polymerisation index. The tanning powers of the fractions were graded according to their reactivities with cinchonine sulphate solution in a standardised turbidometric test. Whereas, almost 75% of the flavanols from Ark Royal barley were non-tanning oligomers almost 96% of the flavanols from Bullion hops were polymeric tannins. Reactivity of most of the barley flavanols with cinchonine sulphate was increased greatly by oxidation with peroxidase and hydrogen peroxide. Some effects of polymerisation, caused by enzyme action or by exposure to air, on oxidisable polyphenols (non-tannins) were measured using (+)-catechin, procyanidin B3 and prodelphinidin B3 in model systems. These, and other measurements on experimental and commercial beers indicated that oxidation of simple flavanols from barley produced polymers with tanning properties. In contrast, the hop flavanols when extracted apparently in their native forms, were capable of co-precipitating with polypeptides in beer. Treatment of beers with different stabilising agents, such as Polyclar AT and silica hydrogel, retarded haze formation by restricting ‘protein-polyphenol’ interactions.     

EUROPEAN BREWERY CONVENTION: HAZE AND FOAM GROUP. TOWARDS THE CHEMICAL PREDICTION OF SHELF LIFE

Rapid chemical methods are described for assesssing in beer the levels of “oxidizable polyphenols” and “sensitive proteins,” both of which influence non-biological shelf life. The method for oxidizable polyphenols depends on the formation of an insoluble complex with cinchonine sulphate. Freshly processed beers form only a slight haze on the addition of cinchonine sulphate, but the haze produced is greatly increased if the beers are previously oxidized. For beers stabilized by a process involving reduction of the polyphenol content, it is found that the rate of haze formation is then directly related to shelf life and is inversely proportional to it.