减少啤酒中铁离子含量的几条措施

铁离子能够促进啤酒沉淀物的形成 ,加速啤酒老化现象的产生 ;铁离子与自由基的产生有直接的关系。因此 ,在啤酒中应降低铁离子的含量 ,以降低其对啤酒质量造成的影响。     

减少碑酒中铁离子含量的几条措施

铁离子能够促进啤酒沉淀物的形成,加速啤酒老化现象的产生;铁离子与自由基的产生有直接的关系.因此,在啤酒中应降低铁离子的含量,以降低其对啤酒质量造成的影响.     

啤酒中的铁离子

铁离子可促进酵母生长发育;又可引起啤酒混浊、产生金属味,降低啤酒质量.啤酒中的铁离子主要来源于原辅材料、设备管件及酿造用水等.铁离子在酿造过程易发生氧化还原、催化和络合反应,对麦汁糖化、发酵及成品啤酒质量产生影响.控制铁离子含量的方法有:控制原辅料及所用水的铁离子含量;适当提高糖化醪液的pH值;选用优良、强壮的酵母种;选用含铁较少的硅藻土助滤剂;选用耐酸不锈钢容器和管道,并作好防腐措施.(孙悟)     

啤酒中铁离子含量的控制

啤酒酿造过程中铁离子（可溶性铁）对麦汁的组成，发酵性能和成品啤酒质量有不同程度的影响。糖化过程中铁离子含量较高，会抑制糖化的进行，加深麦汁色度；发酵阶段铁离子含量过高影响酵母的生长和发酵；清酒灌装以后如果铁离子含量过高，会加速氧化作用。优质成品啤酒中铁离子含量应〈0．10ppm，当铁离子含量〉0．20ppm时，会对成品啤酒产生不同程度的负面影响，当铁离子含量〉0．40ppm时，就有明显的金属腥味和氧化味。[第一段]     

硅藻土过滤阶段影响啤酒抗氧化力的因素与控制

文中结合DPPH和TBA两种分析方法,阐述了硅藻土消耗量、铁离子含量、单宁添加量及啤酒pH值等因素对过滤后啤酒抗氧化力的影响。结果表明,溶入啤酒中铁离子增加,pH值低等会降低啤酒DPPH自由基清除率,即降低了啤酒抗氧化力。     

硅藻土对啤酒中铁离子含量及啤酒质量的影响

目前世界上使用的啤酒助滤剂中，硅藻土占75％～80％。硅藻土中含有可溶性铁，过滤时进入啤酒，铁离子含量过高，对啤酒质量有不利影响。如：易引起铁蛋白混浊、引发啤酒的喷涌病、带给啤酒金属腥味等等。本实验的目的在于，通过检测不同品牌硅藻土的可溶性铁含量，处理后滤发酵液中铁离子含量，结合TBA实验，来评估不同品牌硅藻土对啤酒中铁离子含量及啤酒质量的影响。     

啤酒生产中铁离子的来源及控制措施

啤酒中的铁离子主要来源于原辅材料、设备管件及酿造用水等。对麦汁糖化、发酵及成品啤酒质量产生影响。控制铁离子含量的方法有:控制原辅料及所用水的铁离子含量;适当提高糖化醪液的p H;选用优良、强壮的酵母种;选用含铁较少的硅藻土助滤剂;选用耐酸不锈钢容器和管道,并作好防腐措施。     

啤酒酿造过程中铁离子的来源，变化及其对啤酒质量的影响

研究了啤酒酿造水、原料、添加剂及助剂中的铁含量和铁离子在啤酒酿造过程中的变化规律。原辅料及添加剂中均含有不同浓度的铁,硅藻土含铁量最高,大米最低。麦汁中铁离子浓度均值在0．29mg／L,发酵过程中部分被酵母吸收,大部分随沉淀物排出罐外。成品酒中的铁离子会促进啤酒羰基类化合物的生成从而影响啤酒风味质量,游离态铁离子会使啤酒货架期前期浊度值升高,而对啤酒色度无显著影响。     

影响啤酒冷混浊的主要因素

影响啤酒冷混浊形成的主要因素有铁离子、溶氧、pH值、CO2等。实验证明,微量的铁离子（0．02mg／kg）也会使啤酒产生明显的老化味;溶氧会加速啤酒氧化作用,打破啤酒胶体稳定性、促进啤酒冷混浊产生;酒液的pH值控制应综合考虑多种因素;发酵过程产生大量CO2,低温长时间缓慢溶解于酒内的CO2,有利于酒体的稳定。（孙悟）     

石墨炉原子吸收法测定啤酒中的铁

优质啤酒中铁离子的含量应低于0.1mg/L。啤酒中铁离子含量高对啤酒质量的影响是不言而语的。首先,有资料表明啤酒中含 Fe~(2+)>0.4mg/L,即具有明显的金属腥味,而且会导致啤酒泡沫不洁白。另外,铁离子在啤酒中起着氧化接触剂的作用,会促进啤酒的氧化浑浊,进而导致啤酒的口味败坏。近年来国内啤酒行业对啤酒风味稳定性越来越重视。因此测定啤酒中铁离子的含量就显得尤为重要了。目前国内标准中测定铁离子用的是火焰原子化法,但是使用该法在仪器灵敏度足够的情况下最低才能检出0.05mg/L 的铁。而目前许多企业都需将啤酒中的铁含量控制在0.1mg/L 以下,因此使用灵敏度更高的无火焰技术才能满足测定要求。本文研究的就是使用石墨炉原子化法来测定啤酒中的铁离子含量。     

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.     

锌离子在啤酒酿造中的作用与控制

啤酒中锌离子来源于麦芽、大米、酿造用水、酒花。Zn^2 在啤酒酿造过程中可起到催化荆作用，与氨基酸结合形成Zn-氨基酸螯合物。在啤酒酿造过程中，可激活酶提高酶的作用；促进糖化、发酵；促进蛋白质合成及其稳定性；缓解某金属离子的毒性作用，促进挥发物质的产生和双乙酰的还原，缩短发酵时间，提高啤酒质量；但含量过量会使啤酒非生物稳定性降低，影响啤酒质量。通过对糖化过程和发酵过程的控制，可降低醪液pH值。加入少量小麦芽，加入适量ZnCl2，ZnSO4及酵母营养盐等，可实现对Zn^2 的有效控制，达到最佳酿造浓度。     

The influence of metal ions on concentrations of flavour-active sulphur compounds measured in beer using dynamic headspace sampling

Addition of copper(II) ions (≤1.6 mg litre^?1) to beer significantly reduced (P ≤ 0.05) concentrations of hydrogen sulphide and ethanethiol measured in beer, but had no effect on methyl sulphide, methyl thioacetate and methyl disulphide. Zinc, iron(III), manganese(II), nickel, lead(II) and tin(II) ions, at similar concentrations, had no effect on any of the sulphur volatiles. When metal ions were added at a concentration of 1 glitre^?1 zinc, iron(III) and lead(II) reversibly bound hydrogen sulphide and enthanethiol.     

葡萄糖氧化酶用于改善啤酒风味稳定性存在的缺陷及改进措施

啤酒的风味稳定性已成为影响啤酒质量的一个限制性因素。因为啤酒的风味稳定性与啤酒的含氧量有密切的关系，因此，除去啤酒中的氧，可明显改善啤酒的风味稳定性。葡萄糖氧化酶可用于脱除啤酒中的氧，但在改善啤酒风味稳定性方面还存在一定的缺陷。介绍了葡萄糖氧化酶用于啤酒脱氧的缺陷及改进措施。     

EFFECT OF CALCIUM IONS IN SORGHUM BEER MASHING

One of the problems in sorghum beer brewing is that of sugar production. This is because sorghum malts are low in diastatic activity, the grist contains a high proportion of adjunct and in some brewing processes conversion is carried out at pH 4. Since the positive effects of calcium ions on alpha-amylase activity are well described, the use of additional calcium in sorghum mashing was investigated. Mashing at pH 4.5 in the presence of 0.1% calcium acetate (227 ppm Ca) resulted in almost complete conservation of diastatic activity during conversion and higher reducing sugar production compared with tap water (31 ppm Ca). At a mash pH of 4, a calcium ion concentration of approximately 200 ppm gave maximum reducing sugar production and wort yield and increased extract. Under these conditions, some alpha-amylase activity was detected at the end of the conversion, whereas without calcium no alpha-amylase activity was detected. It, therefore, appears that improved conversion took place due to the conservation of alpha-amylase activity by calcium ions. The inclusion of additional calcium ions in sorghum beer mashes also enabled the same amount of sugar production compared with straight tap water but using a substantially lower proportion of malt in the grist.     

啤酒的喷涌及预防

啤酒的喷涌指包装啤酒(瓶装或罐装)开盖后二氧化碳突然冒出，引起大量很细的泡沫溢出，导致泡沫状啤酒流出容器之外。影响啤酒喷涌的因素有：原料、酒花、草酸钙结晶、金属离子、肽及含肽物；影响喷涌强度的因素包括：搅动与振荡、温度、容器、二氧化碳、瓶颈空气；预防啤酒喷涌的方法：选用优质原料、尽量杜绝金属离子进入啤酒、采取沉淀或溶解法除去啤酒中草酸钙结晶、使用抗氧化剂除去啤酒中溶解氧、减少瓶颈空气含量和正确运输、贮存及装卸。     

THE INSTITUTE OF BREWING ANALYSIS COMMITTEE DETERMINATION OF IRON IN BEER

The method recommended for the determination of iron in beer utilizes a technique devised by the Alfred Jorgensen Laboratory. After reduction to the divalent state, iron is estimated spectrophotometrically as the coloured complex with 2,2′-dipyridyl, the absorbance of the final solution being measured at 528 mμ.     

DETERMINATION OF THE FILTERABILITY OF BEER

A method for the determination of the filterability of beer has been evaluated by members of the European Brewery Convention Analysis Committee. The method is based on the filtration of a beer sample, with a standard amount of diatomaceous earth (DE), under standardised conditions. Repeatability of the test was quite good, however the predictive value of the test is still questionable since no direct correlation could be established between the different filtercake values and industrial filtration problems. No collaborative test was performed as the filterability has to be determined on unfiltered beer; the test is easy to run, and as for the other filterability tests, day to day practice in a brewery will reveal its usefulness.