酯类物质含量对啤酒风味影响的研究

啤酒中的酯类物质含量对啤酒风味有重要的影响。应用感官分析法和正交试验研究了酯类物质含量对啤酒风味的影响,确定了啤酒中4种主要酯类物质含量的最佳范围,依次为20～25mg/L乙酸乙酯、1.00～1.50mg/L乙酸异戊酯、0.150～0.250mg/L己酸乙酯和0.150～0.300mg/L丁酸乙酯。     

影响啤酒风味物质的因素

影响啤酒风味的物质很多，它们大都是有机化合物，可分为醇、酯、酸、羧基化合物、含硫化合物、酚基化合物等。啤酒生产过程的原辅材料、酵母菌种、水及生产工艺过程与这些物质产生的多少有着密切的关系。     

啤酒发酵对啤酒质量的影响和控制

啤酒的风味物质主要是酵母在发酵过程中代谢产生,因此发酵是啤酒风味形成的基础,对啤酒质量有较大影响.     

啤酒中的含硫化合物对啤酒风味的影响

啤酒中很多含硫化合物是强风味物质，虽然浓度较低，但对啤酒风味的影响很大，特别是一些低分子量的含硫化合物对风味的影响更大，而且这些作用常常是有效的，论述了啤酒中重要的含硫化合物的种类，来源，及主要影响因素，并阐述某些含硫化合物的气相色谱分析方法。     

啤酒发酵方法对质量的影响

啤酒发酵温度越高，酵母代谢速度越快，能明显缩短发酵周期，但同时也使得影响啤酒风味的高级醇类，酯类，酮类物质的增加，啤酒口味变坏。增加发酵的压力能够改善啤酒由高温发酵所带来的不良因素的影响，从而获得较短的发酵周期和满意的啤酒风味质量。     

浅议发酵副产物对啤酒风味的影响及改进措施

从不同的发酵工艺会对啤酒风味造成不同的影响，提出如何通过合理的工艺操作来控制影响啤酒风味的物质的含量，从而保证啤酒的风味稳定圆满。     

酵母合成酯类风味物质发酵条件的优化

文中对影响产酯酵母合成酯类的影响因素进行了研究。采用均匀设计试验考察了ＮＨ４Ｈ２ＰＯ４、ＭｇＳＯ４．７Ｈ２Ｏ及ＫＨ２ＰＯ４对产酯的影响。通过回归分析获得了产酯与三种培养基成分的数学模型。。与正交设计相比，均匀设计具有试验次数少，工作效率高和便于分析等优点。     

啤酒发酵过程对重要醇酯影响的研究

风味物质的含量决定啤酒的品质,其特征会直接决定啤酒口感和其市场竞争力。研究了麦汁浓度、主酵温度和接种量对啤酒中风味物质的影响。在不同的发酵条件下,以全麦芽为原料,经下面发酵生产啤酒。采用顶空气相色谱法检测啤酒中高级醇和酯类的浓度。研究发现麦汁浓度对高级醇和酯的影响最大,且提高麦汁浓度能够同时增大啤酒中高级醇和酯的含量,当麦汁浓度从11°P提高到15°P,乙酸乙酯的含量提高了34%。在相同接种量和麦汁浓度下,主酵温度越高,异戊醇含量越高,异丁醇的含量却有所降低。在较高的发酵温度下乙酸乙酯、辛酸乙酯和乙酸异戊酯的含量升高,但是己酸乙酯的含量变化无规律。研究结果显示接种量对醇和酯的影响都不显著。     

The Influence of Heavy Metal Ions on Beer Flavour Stability

In this study, the importance of iron and copper ions and their radical formation via the respective Fenton and Haber‐Weiss reactions was confirmed. Of the other heavy metals present in the brewing process in relevant concentrations, the impact of manganese ions on beer flavour stability has been elucidated. In contrast to iron and copper, manganese ions are not removed from wort or beer to any great extent during the process. Additionally, manganese shows a similar radical‐promoting effect to that seen with iron and copper. Its reactivity, and typically higher concentration than the other two metals in beer, appear to make manganese an especially potent pro‐oxidant in beer. The results of the investigation clearly indicate that there are other heavy metals influencing the stale flavour characteristics of beer, in addition to the well‐known metals, iron and copper. In contrast to the aforementioned ions, manganese does not enter the product by being leached out of a tank or from piping materials, but rather comes from the cereals employed in brewing. This finding, concerning the importance of manganese as a redox system in beer staling, can serve as a basis for a different approach in the choice of raw materials.     

浅谈影响啤酒色泽的因素

色度是啤酒一项重要理化指标。本文主要论述了啤酒色度的形成机理,影响啤酒色泽形成的因素以及改进啤酒色泽的工艺措施。     

蔗糖酯对乳体系影响作用的研究

本文从乳化剂的作用机理出发,考察了不同蔗糖酯添加量对牛奶的稳定性系数、粒度分布、粘度以及Zeta电势的影响,从而为蔗糖酯的应用提供一定的理论指导。通过实验得出,蔗糖酯可以提高牛奶体系的稳定性系数、阻止颗粒的聚集、增大粘度和颗粒电势绝对值。其中当蔗糖酯的添加量为0.12%时牛奶体系最稳定。     

啤酒多酚物质对啤酒风味稳定性的影响

多酚是啤酒中重要的风味物质，对啤酒质量（非生物稳定性、风味稳定性以及口味）有着重要的影响。作者分析了啤酒中多酚物质的来源以及对啤酒风味稳定性的影响，并利用高效液相色谱测定了啤酒多酚中的单酚物质，研究发现其中的（＋）-儿茶素、（-）-表儿茶素、阿魏酸和槲皮素等单酚具有较高的抗氧化能力。     

Influence of Pasteurising Intensity on Beer Flavour Stability

While it is preferred that flavour improves during the beer maturation process, formation of undesirable flavours inevitably occurs during beer storage. Beer ageing problems occur during beer storage and can damage the beer style, especially for lager beer of a more delicate style. In this research, the impact of pasteurising intensity on beer ageing and flavour stability was studied. Through process adjustments, three types of bottled beer were obtained from one fermenter and classified by their PU values as 2 PU, 8 PU and 14 PU. The dynamic changes of related indices (taken every month) characterizing the ageing and flavour of the beer under different pasteurising intensities were investigated during a 6‐month room temperature storage period. The key factors of colour, the thiobarbituric acid (TBA) index, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity, bitterness and total polyphenol composition, the concentration of beer volatile compounds (BVCs), and 5‐hydroxymethyl furfural (5‐HMF) were examined. Statistically, the 14 PU sample showed the highest degree of damage, with the greatest flavour change compared to the other samples.     

The Influence of Hopping on Formation of Carbonyl Compounds During Storage of Beer

Improving beer flavour stability is an important brewing goal. Pilot scale brewing trials (50 L) were performed that focused on the determination of the influence of hop pellet dosage and dosage timing on carbonyl compounds in stored beer. The reducing activity of experimental worts, beers and stored beers appeared to depend on the hop pellet dose. Brews with lower amounts of hop antioxidants showed an enhanced formation of carbonyl compounds over the course of beer storage. A correlation between DPPH reducing activity and the content of some carbonyls, including the important markers 2‐furfural and (E)‐2‐nonenal, was found. Fresh and aged beers hopped by different amounts of hop pellet doses were clearly distinguishable according to their carbonyl content using Cluster analysis. Results of the sensorial analysis corresponded to the analytical criteria values. Results of this study bring further evidence of the indispensable impact of hop antioxidants on the suppression of undesirable carbonyl compound formation in the course of beer staling, which can be significant in beers hopped by aroma hops. However, hop antioxidants are only one of many factors affecting beer staling.     

国外对啤酒风味活性酯类形成与调控的认识

挥发性酯类可以给啤酒带来水果香味,是啤酒中一类重要的风味活性物质。如今,使用大型锥形罐进行高浓酿造日益兴盛,但容易引起发酵体系酯类不平衡,使啤酒品质下降。目前,在麦汁充氧、麦汁组成、发酵罐设计等关键因素对酯类形成的影响方面,取得了一定的研究进展。啤酒厂可通过优化这些因素,在实际操作中有目的地调控酯类的形成,控制成品啤酒的风味。综述了啤酒生产过程中有关酯类形成的生化反应的相关研究,并讨论了啤酒生产过程控制酯类形成的调节措施。     

离子对啤酒酵母代谢产酸的影响

在离子型培养基中分别添加6.804,13.610,27.216 g/L 的KH2PO4以及66.39,138.75, 277.4 mg /L 的CaCl2,对通风发酵过程中的不同K^＋、Ca^2＋浓度影响啤酒酵母代谢产6种有机酸含量的动态变化进行了跟踪检测.研究结果表明,K^＋、Ca^2＋可能通过作用于酵母细胞膜上的膜蛋白或调控生理代谢网络中代谢流相关的酶,从而使不同的K^＋、Ca^2＋浓度影响啤酒酵母响应产酸的峰值和峰值响应时间;在通风发酵过程中,啤酒酵母代谢产乳酸较多（多达8.3 mg/mL）,产琥珀酸较少（不超过250 μg/mL）;发酵终点时,随K^＋、Ca^2＋浓度增大,啤酒酵母代谢产酒石酸和琥珀酸等含量减少.     

优化固相微萃取条件以检测啤酒中高级醇和酯

采用固相萃取-气相色谱-质谱联用仪(SPME-GC/MS)对啤酒中高级醇和酯类进行检测.采用Hackett-Burman多因素实验设计和Box-Behnken实验设计,对影响固相微萃取效率的因素进行优化.通过响应面分析和典型性分析得出最佳萃取条件为:萃取温度55.01℃,萃取时间48.32min,氯化钠添加量3.10 g;在该条件下,总相对峰面积达到55.67.乙酸乙酯、异戊醇等物质的回收率均在93.12%～102.49%之间.该法灵敏度高,可准确检测啤酒中的高级醇和酯类.