提高啤酒口味纯正度的探讨

随着啤酒企业精细化操作的要求和消费者对啤酒口味要求的愈来愈高，如何提高产品口味的纯正度，成为近年来各啤酒企业重视的课题，我公司也在这方面做了较多的工作，具体实施了以下几项措施：     

浅论啤酒的口味

中国的啤酒发展异常迅猛，据统计９８年全国共生产啤酒１９００万吨，位居世界第二。随首人们生活水平的日益提高，质量意识、消费意识的逐渐增强，人们对啤酒质量的要求也越工高，特别是啤酒的风味的风味稳定性和口味一致性，已成为消费者衡量质量好坏的主要依据。     

啤酒口味稳定性的研究

啤酒作为一种食品,从产成品出厂到消费者饮用有一定的时间限制,国家标准GB4927—91规定,优级、一级啤酒保质期为120天,二级啤酒保质期为60天,罐装、桶装或瓶装鲜啤酒保存期则更短,只有几天。这就要求不同档次的啤酒要在相应的保质期里保证理化、卫生指标的稳定和色、香、味、泡沫及形体外观的基本稳定。随着人民生活水平的提高和啤酒市场供需矛盾的转化,消费者对啤酒的认识水平、鉴赏能力不断提高,对啤酒的挑选亦愈严格,质量稳定与否就决定了产品的竞争能力。质量不稳定的一个重要方面就反映在保存期内外观和口味的不稳定上,如雾浊、失     

工艺条件对啤酒口味稳定性的影响

减少啤酒中氧含量是解决啤酒口味稳定性的关键因素。方法有：(1)在发芽过程中，对通氧量予以控制，降低麦层中含氧量；(2)干燥过程从50℃升至70℃，以2℃／11温升速度制备麦芽；(3)麦皮糖化法可抑制啤酒风味物质氧化；(4)控制醪液pH值为5．2；(5)糖化过程可提高下料温度，防止高分子蛋白质过度分解；(6)麦汁煮沸时间以60～70min为宜；(7)缩短麦汁在沉淀槽的停留时间；(8)控制好发酵温度；(9)在过滤与灌装过程采取有效措施，尽可能减少吸氧量。     

影响啤酒口味的因素及其控制

本文分析了影响啤酒口味的因素，并结合生产实际，提出如何控制这些因素，防止啤酒产生不良口味。     

不可忽视口味质量对啤酒市场的影响

本文就影响我国啤酒口味质量的主要问题－成品酒中双乙酰含量偏高或超标－形成的原因与途径，提出了可以采取的几种措施以及确保啤酒口味质量的最佳选择。     

浅谈啤酒口味的稳定性

论述了老化口味是啤酒口味变场的典型代表，避免氧化的措施。     

浅谈啤酒的口味一致性

1啤酒风味稳定性和口味一致性的关系 瓶装啤酒从下了生产线以后，随着时间的推移，口味将逐步变差。“新鲜感”已经成为消费者评价啤酒质量优劣的一个最重要的因素。因此，稳定啤酒风味，延长其保鲜期是当前各啤酒生产厂家面临的最大挑战，也是众多科技人员研究的一个新领域。     

Influence of the range of molecular weight distribution of beer components on the intensity of palate fullness

The effect of the molecular weight distribution (MWD) of the beer components on the intensity of palate fullness was studied. The range of MWD for different types of maltodextrin and for nine commercial pilsner beers was determined using AF4/MALLS/RI. Sensory analysis (DIN 10952, DIN ISO 4120 and DIN 10963/ISO 8587) was carried out by a trained Deutsche Landwirtschafts-Gesellschaft, German Agriculture Society (DLG) tasting panel. The intensity of the palate fullness of a spiking trial (beer + maltodextrin) and the threshold concentration of the maltodextrins in beer was determined. The association between the ranges of MWD and the intensity of the palate fullness of the commercial pilsner beers was studied. AF4/MALLS/RI and sensory analysis were used to study the effect of variations of the brewing process on the range of MWD and the palate fullness of beer. The intensity of the palate fullness differed significantly (p < 0.0001) within commercial pilsner beers. Strong associations were found between the range of MWD of the commercial beers and intensity of the palate fullness (p < 0.05). The range of MWD of the commercial pilsner beers (3–13 kDa) corresponded to those found for maltodextrins with intermediated range of MWD (3.4–22.3 kDa). The threshold concentration was higher (p < 0.0001) for those maltodextrins with lower range of MWD (2.7–8.9 kDa). Beers produced with malted barley with Kolbach Index of 36 % exhibited a higher range of MWD (2.9–13 kDa) compared to those with Kolbach Index of 41 % (1.7–11.6 kDa). Slight differences in the palate fullness were perceived according to variations on the initial temperature of the mashing process among those beers produced using Kolbach Index of 36 %, whereas a great difference (p < 0.0001) was perceived using Kolbach Index of 41 %. The intensity of the palate fullness of the pilsner beer was influenced by the range of MWD of the beer components which would vary according to differences in the mashing process and of the quality of the malted barley.     

Influence of high molecular weight polypeptides on the mouthfeel of commercial beer

Low malt beers have high sales volumes in Japan, but improving their mouthfeel, including softness, smoothness and decreasing astringency, is challenging because the compounds responsible remain unclear. In this study, beer was fractionated by preparative size‐exclusion chromatography, with the polypeptide and maltodextrin fractions purified using solid‐phase extraction and ion‐exchange resin. Sensory data from a spike test showed that the mouthfeel (softness, smoothness, and reduced astringency) of low malt beer was improved both by the degree of polymerisation (DP) of maltodextrins (DP of 2‐10; at increased concentration of 40 to 60%; P < 0.01) and by 10 ‐ 20 kilodalton (kDa) high molecular weight (HMW) polypeptide and 2‐3 kDa low molecular weight polypeptide fractions (at a 50% increase in concentration; P < 0.01). Furthermore, highly purified 10 to 20 kDa HMW polypeptides improved the softness and smoothness and decreased the astringency (at a 25% increase in concentration). This report is the first to provide experimental sensory data indicating that HMW polypeptides improve the mouthfeel of beer. Based on these findings, a new low malt beer was developed that showed significantly higher levels of the 10‐20 kDa HMW polypeptides with an overall improved mouthfeel. Mass spectrometric analysis of the 10 to 20 kDa proteins identified several unique foam positive proteins, including barley dimeric alpha‐amylase inhibitor‐1 and non‐specific lipid‐transfer protein 1. These 10‐20 kDa HMW proteins are likely to be responsible for the improved mouthfeel of beer. © 2020 Kirin Holdings Kabushik Kaisha Co. Ltd. Journal of the Institute of Brewing published by John Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling     

Determination of the influence of starch sources and mashing procedures on the range of the molecular weight distribution of beer using field‐flow fractionation

To produce experimental beers, different mash mixtures (barley malt, barley malt + 30% pre‐cooked maize, barley malt + 30% nonmalted spelt) and distinct mashing procedures (infusion and decoction) with variations of the rest time and initial temperatures were evaluated. The range of molecular weight distribution (MWD) of the resulting beers was determined using asymmetrical flow field flow fractionation coupled to multiangle laser light scattering and refractive index. There were no differences on the range of MWD among the beers, according to infusion or decoction, using similar raw materials and initial temperatures (45 and 55°C). However the range of MWD was higher (p < 0.005) when using infusion at an initial temperature of 63°C, regardless of the raw material. The use of maize did not alter structural properties of the beer, while mash containing nonmalting spelt caused an elevation on the MWD (p < 0.001) and a lower (p < 0.05) apparent degree of fermentation. Therefore the range of the MWD of the beers was influenced by the quality of the raw material and the initial mashing temperature, whereas apparent degree of fermentation values were affected only by the type of starch source. Thus the determination of the MWD is an important tool for monitoring the production of beer. Copyright © 2013 The Institute of Brewing & Distilling     

啤酒组分与泡沫稳定性的相关性研究

选取26种国内外市售啤酒为研究对象,分别利用国标法、考马斯亮蓝法和美国酿造化学家协会分析法(ASBC法)检测了啤酒泡持性、总蛋白、总糖、总多酚、粘度、pH及酒精度。结果显示:总糖、总多酚、总蛋白和黏度对啤酒泡持性的相关度较高,而pH和酒精度对泡持性影响不大。     

萌芽黑豆中蛋白质组分分子量分布及其抗氧化活性研究

本文目的是研究萌芽黑豆中不同蛋白质组分的分子量分布,以及各组分的抗氧化活性。采用碱提酸沉法获得萌芽黑豆中的蛋白质,通过硫酸铵盐析法逐级分离各蛋白质组分,SDS-PAGE法测定各蛋白质组分分子量分布,并从清除自由基和抗人皮肤成纤维细胞氧化损伤两个方面研究了各蛋白质组分的抗氧化活性。萌芽黑豆中蛋白质组分可以集中分离为三个部分,其分子量分布为140.0¹66.0、45.0⁷2.0、17.0²3.0ku;清除自由基和抗人皮肤成纤维细胞氧化损伤的实验结果均表明分子量在17.0²3.0ku的蛋白质组分具有最优的抗氧化活性,说明低分子量的萌芽黑豆蛋白质具有更强的抗氧化活性。      

Changes in protein molecular weight during cloudy wheat beer brewing

To investigate the changes in protein in cloudy wheat beer (CWB) brewing, the molecular weight (M_w) of protein components in wort, fermenting wort, beer and beer foam were analysed by high‐performance size‐exclusion chromatography. It was found that the M_w of protein during brewing was mainly distributed between 100 and 0 kDa. From mash to the final beer, the most abundant protein component was the 7.6–2.1 kDa fraction, which occupied more than 40% of the total protein. The extraction of soluble protein from malts into wort mainly focused on the protein rest process, where the 100.0–32.1 and 7.6–2.1 kDa fractions increased significantly. In addition, the 100.0–13.2 kDa fraction was the predominant thermolabile protein that decreased during lautering and boiling. The dominant protein constituting the fine coagulum, the 100.0–13.2 kDa fraction, also decreased during fermentation and maturation. The CWB, defoamed CWB and CWB foam had similar protein M_w distributions, while the CWB foam concentrated much more protein and the 7.6–2.1 kDa fraction was the major protein in the CWB foam. Copyright © 2015 The Institute of Brewing & Distilling     

超声波强度分布对促染作用的影响

超声波对染色过程具有促进作用,探讨了超声波在透过织物时的衰减变化及超声场强度分布对促染作用的影响.结果表明:在靠近换能器的0.9 cm处,超声声压级分布不均匀,在换能器的垂直上方声压最高,此深度处超声波透过织物的衰减率随径向间距增大而减小;在远离换能器的5.4 cm处,超声声压级分布均匀,超声波透过织物的衰减率基本恒定.染色时,超声波在布面2侧的衰减率越高,染色织物的颜色越深.但超声波的促染作用与织物类型密切相关,汉麻织物的颜色深度均低于纯棉织物.     

Mechanical properties of mammalian and fish gelatins based on their weight average molecular weight and molecular weight distribution

Acid porcine skin gelatins (type A), lime bone gelatins (type B) and gelatin from different cold water fish species were compared on the basis of low deformation mechanical properties, Bloom value, weight average molecular weight, molecular weight distribution and isoelectric point. The dynamic storage modulus and Bloom value for all types of gelatin increased with increasing weight average molecular weight. Type A and type B gelatins with similar weight average molecular weight exhibited different dynamic storage modulus (G′) and different Bloom values. This is most probably due to a different molecular weight distribution as well as the presence of different hydrolytic fragments. The present study suggests that it may be possible to improve the mechanical properties by removing low molecular weight molecules from a gelatin sample. The Bloom values for gelatin from haddock, saithe and cod were determined to be 200, 150 and 100 g from a linear correlation between G′ and Bloom.     

Calculated molecular weight distribution for glutenin

The size distribution of linear glutenin molecules has been calculated using standard theory of high polymers. If the degree of polymerisation (DP) is defined as the number ofsubunits in a molecule, the DP distribution is expressed by a single variable, b, the reciprocal of the number-average DP. For a DP of i, the weight- and number-fractions are, respectively, ib²(1?b)^i?1. and b(1?b)^i?1. The weight-average DP is (2/b)?I. The distribution is identical with that produced by random degradation of an infinite molecule (b being the fraction of interchain disulphide bonds broken). The distribution predicts that there would be a significant amount of low mol. wt material: this is so in practice, such material being soluble in aqueous ethanol. The shape of a calculated curve corresponds, at least qualitatively, to those in the literature obtained by gel filtration when allowance is made for the mol. wt axis being on a logarithmic scale, for the longest molecules emerging together in the excluded peak and for diffusion. These experimental curves show that monomers are not the commonest species by weight (unless half gliadin consists of monomeric glutenin). This implies that glutenin has a linear, not a branched, molecule.     

燕麦多糖的提取工艺及分子量分布研究

通过单因素实验和正交实验研究了燕麦多糖的提取条件,并采用Sephadex G-75色谱柱对燕麦多糖进行了纯化,采用高效液相色谱法测定了燕麦多糖的分子量分布。结果表明,燕麦多糖的最佳提取条件为:提取温度60℃,料液比1∶10,提取时间1.5h,提取3次,该条件下燕麦多糖得率为10.92±0.03g/100g。高效液相色谱测定结果表明,燕麦多糖是由分子量为400～600kDa和150kDa两部分组成的。