啤酒腐败微生物与啤酒微生物稳定性研究进展

尽管生产环境和卫生条件已经得到大幅改善,但啤酒生产过程中仍然会发生微生物污染,因此,真正意义上的啤酒纯种酿制是很难实现的。为了有效控制生产过程中的微生物污染,本文系统介绍了啤酒微生物的多样性及其在生产工序中的分布,探讨了啤酒环境对抑制啤酒微生物污染的影响,讨论了啤酒微生物对啤酒质量与风味的积极贡献,提出合理控制外源微生物侵染是形成不同啤酒典型特征的关键。     

Pitcairnia carnea Beer

Ohne Zusammenfassung     

Studies on the Sunlight Flavor of Beer

Three synthetic lupulone analogues, i.e., 1-acetyl-3,3,5-tri-allyl-, 1-acetyl-3,3,5-tri-n-propyl-and 1-acetyl-3,3,5-tri-n-butyl-hexadiene- (1,5) -diol- (2,6) -on- (4) did not cause sunlight flavor of beer when they were added to a fermented solution of sucrose and exposed to sunlight.

When methanol solutions of humulone and acetolupuphenonen were exposed to sunlight, changes in the UV-absorption spectra were observed. This fact indicates that humulone and acetolupuphenone underwent some photochemical reaction upon exposure to sunlight.

Prenyl (γ,γ-dimethylallyl) mercaptan was synthesized, which gave a typical sunlight flavor when it was added, in a trace amount, to a fermented solution of sucrose.     

Quantitative Evaluation of Sunstruck Flavor of Beer

Judgement of sunstruck flavor of beer has been relying on the sensory evaluation. However, this sensory test is inaccurate, as well known. Utilizing the experimental result that sunstruck flavor is caught completely with silver nitrate, the authors established a potentiometric method for the determination of sunstruck flavor substance of beer by expressing its intensity in the amount of silver ions combined with it.     

Studies on the Sunlight Flavour of Beer

In order to establish the mechanism of occurrence of sunlight flavour of beer in continuation of the preceding paper, humulone, lupulone, and their analogues and degradation compounds, i.e., cohumulone, adhumulone, 5-acetyl-3-methylfilicinic acid including analogues, tetrahydrohumulone, hexahydrolupulone, humulinic acid and lupuloxinic acid, were tested for the occurrence of sunlight flavour of beer.

As a result, among the above-mentioned compounds, humulone, lupulone, cohumulone, adhumulone, tetrahydrohumulone and hexahydrolupulone were found to cause the sunlight flavour, but the other compounds did not cause typical sunlight flavour. This fact shows that some specific structural components seem requisite for the occurrence of sunlight flavour of beer.

It was also revealed that isomerization caused by boiling accelerates the occurrence of the sunlight flavour of beer. Finally, the result of the experiment conducted by the gas chromatographic procedure showed that any new component is not detected by the exposure of beer to sunlight but, two components somewhat increased.     

Beer increases plasma antioxidant capacity in humans

The positive association of a moderate intake of alcoholic beverages with a low risk for cardiovascular disease, in addition to ethanol itself, may be linked to their polyphenol content. This article describes the effect of acute ingestion of beer, dealcoholized beer, and ethanol (4.5% v/v) on the total plasma antioxidant status of subjects, and the change in the high performance liquid chromatography profile of some selected phenolic acids (caffeic, sinapic, syringic, and vanillic acids) in 14 healthy humans. Plasma was collected at various times: before (T0), 1 hour after (T1), and 2 hours after (T2) drinking. The study is part of a larger research planned to identify both the impact of brewing on minor components potentially present in beer and their metabolic fate in humans. Beer was able to induce a significant (P < 0.05) increase in plasma antioxidant capacity at T1 (mean +/- SD: T0 1,353 +/- 320 microM; T1 1,578 +/- 282 microM), returning close to basal values at T2. All phenolic acids measured in plasma tended to increase after beer intake (20% at T1, 40% at T2). Syringic and sinapic acid reached statistical significance (P < 0.05 by one-way analysis of variance-Fisher's test) at T1 and T2, respectively. Plasma metabolic parameters (glucose, total cholesterol, triglycerides, and uric acid) and plasma antioxidants (alpha-tocopherol and glutathione) remained unchanged. Ethanol removal impaired the absorption of phenolic acids, which did not change over the time of the experiment, accounting for the low (and not statistically significant) increase in plasma antioxidant capacity after dealcoholized beer drinking. Ethanol alone did not affect plasma antioxidant capacity or any of the antioxidant and metabolic parameters measured.     

利用固化技术生产麦花啤

麦花啤是一种发酵饮料,深受广大消费者欢迎,但是旧生产工艺是自然发酵,即不能保证产品质量,而且又由于杂菌污染,而导致爆瓶,甚至伤人,后果严重,用固化酵母新技术生产麦花啤,完全克服了上述问题,结果十分令人满意。     

Hopped Beer: The Case For Cultivation

The history of hops, hopped beer, and hop cultivation is unclear and ambiguous. An assessment of the available literature reveals many contradictions, especially regarding the first use of hops in beer and the earliest incidence of hop cultivation. Historically, hops were used for a variety of purposes; now their primary use is as a preservative and flavoring in beer. Hop cultivation is poorly documented, but was certainly undertaken by the 10th century, most probably in response to the demand generated by beer-brewing. After comparing the literature and investigating source material, a chronology of hop use in beer and hop cultivation is proposed.     

Studies of the Sunlight Flavor of Beer

The recent findings^1~3) that prenylmercaptan (3-methyl-2-butene-1-thiol) is the major component of the sunlight flavor of beer has led us to investigate the pathway of its evolution. S-Prenyl-l-cysteine, S-(3-methyl-2-butenyl)-l-cysteine, was synthesized according to the general outline of A. Stoll et al.⁴⁾ from l-cyteine and prenylbromide, since it was considered as one of the precursors of the sunlight flavor of beer. S-Prenyl-l-cysteine was a colorless and odorless crystal, but this compound generated prenylmercaptan when the aqueous solution was exposed to sunlight. The addition of a small amount of riboflavin to the solution as a photosensitizer increased the mercaptan evolution. Prenylmercaptan formed by sunlight was isolated as its 2,4-dinitrophenyl derivative and identified by the comparison of melting point, chromatographic behavior and infrared spectrum with an authentic sample and by its elemental analysis.     

多元分析用于啤酒风味的研究

通过检测国内外30种不同品牌啤酒中13种主要风味物质,采用多元统计方法中的主成分分析,得到3个主成分及综合风味特征得分;对这些酒样进行感官品评并采用频数分析计算得分．结果发现两种评分结果具有较好的对应性,初步表明根据啤酒中13种风味物质的检测结果,基本能够对啤酒的整体风味进行评判与质量监控．     

电融合构建嗜杀啤酒酵母及其发酵性能的研究

以ＭＫ２－３：Ｋ＾＋Ｒ＾＋ｌｅｕ＾－ｐ＾＋（ｎ）为供体菌,ＡＳ２４２０－１;Ｋ＾－Ｐ＾－ｌｅｕ＾＋ｐ＾０（２ｎ）为受体菌,通过电融合技术构建一批嗜杀啤酒酵母。其中４株融合子具有较高的嗜杀活性,对这４株融合子的遗传性状、ＤＮＡ含主细胞大小、形态、嗜杀质粒ｄｓ－ＲＮＡ提取及电泳等研究表明,这４株菌具有双亲的互补性。对其中ＭＡＲ１的进一步实验表明,ＭＡＲ１的某些发酵性能接近甚至优于亲株ＡＳ２４２０－１,