大麦麦芽非淀粉多糖的含量和分子质量与其协定麦汁过滤速度的关系

以17个大麦麦芽样品为研究对象,采用协定糖化法分析了麦汁中与麦芽过滤速度相关的指标。Pearson相关性分析表明,过滤速度与黏度极显著负相关,与总阿拉伯木聚糖含量显著负相关;黏度与总阿拉伯木聚糖含量极显著正相关,与麦汁中的总β-葡聚糖含量显著正相关。β-葡聚糖和阿拉伯木聚糖分别用75%饱和度的硫酸铵和80%的乙醇沉淀后,采用凝胶过滤色谱法进一步分析了分子量大于1 000 kDa、500~1 000 kDa、50~500 kDa及小于50 kDa的4个分子量段β-葡聚糖和阿拉伯木聚糖的含量,相关性分析结果表明,分子量大于50kDa的阿拉伯木聚糖含量与过滤速度极显著负相关,与黏度极显著正相关;分子量大于1 000 kDa的β-葡聚糖含量与黏度极显著正相关,与总β-葡聚糖含量和总阿拉伯木聚糖含量相比,显著性水平和相关系数均有较大提高,是造成协定麦汁黏度高和过滤速度慢的重要因素。     

阿魏酸酯酶对麦汁过滤性能的影响

研究比较了过滤性能良好的Scope大麦麦芽与存在过滤问题的单二麦芽的水溶性蛋白质组差异,发现参与阿拉伯木聚糖降解的阿拉伯木聚糖呋喃糖苷酶、阿魏酸酯酶存在较大差异,对水溶性阿拉伯木聚糖成分分析发现,单二麦芽中具有较高含量的阿魏酸,推测阿魏酸酯酶缺失是单二麦芽过滤性能缺陷的原因之一,通过添加纯化的阿魏酸酯酶,可有效提高麦汁的过滤速度,降低麦汁浊度和黏度。进一步研究发现,阿魏酸酯酶可有效去除阿拉伯木聚糖侧链上的阿魏酸,从而使得其氧化交联减弱,多聚阿拉伯木聚糖含量降低。     

浊度与啤酒组成的相关性研究

研究了16种商品干啤酒浊度与啤酒原浓(7.98～10.39 °P)、酒精度和发酵度、酸和pH、黏度、含氮化合物(总氮、高分子氮、中分子氮、低分子氮、α-氨基酸)、β-葡聚糖及阿拉伯木聚糖之间的相关性.研究结果表明啤酒的浊度与啤酒的原浓、酒精度、真正发酵度呈极显著负相关(P＜0.01),且显著性依次增强;与啤酒pH呈显著正相关(P＜0.05),但与啤酒总酸无相关性;与啤酒的色度、黏度、贮存时间呈极显著正相关(P＜0.01).然而浊度与啤酒中的含氮化合物无显著相关性,与β-葡聚糖(21.14～51.33 mg/L)、阿拉伯木聚糖(794.80～1090.80 mg/L)和溶解氧(0.04～0.12 mg/L)无相关性.     

麦芽蛋白溶解度与麦汁高分子蛋白的关系

测定了40个不同麦芽样品的蛋白质含量、可溶性氮、库值及高分子蛋白,并对结果进行了相关性分析。结果表明,麦汁中高分子蛋白的含量与麦芽的蛋白质含量呈显著正相关(r=0.659,P0.01),表明蛋白质含量高的麦芽制得的麦汁中高分子蛋白的量也高。此外,建立了麦汁中高分子蛋白与库值及蛋白质含量的线性回归方程,依据此方程可根据麦芽的库值及蛋白质含量预测麦汁中的高分子蛋白,为从源头上预测和控制啤酒泡沫提供支持。     

大麦麦芽阿拉伯木聚糖的研究进展

随着纯生啤酒等高端啤酒产量的增加,啤酒生产对影响黏度和过滤速度的大分子物质含量的要求越来越高。阿拉伯木聚糖是组成大麦胚乳细胞壁的主要非淀粉多糖之一,能够形成高黏度的溶液,影响麦汁和啤酒的黏度和过滤速度。文中从结构、含量的检测、降解及研究展望等方面分析了大麦麦芽阿拉伯木聚糖的研究现状,指出了存在的问题。建立准确的高分子量阿拉伯木聚糖检测方法,研究不同分子量的阿拉伯木聚糖含量对黏度和过滤速度的影响,研究大麦麦芽的内源木聚糖酶抑制剂对阿拉伯木聚糖降解的影响以及高效降解阿拉伯木聚糖的酶制剂配方是今后的发展方向。     

阿拉伯木聚糖强化对面团特性和面包烘焙品质的影响

研究阿拉伯木聚糖的添加量对复合面包粉（小麦淀粉-谷朊粉）的加工特性和面包烘焙特性的影响。结果表明：添加阿拉伯木聚糖后,面团体系黏弹性增加,蠕变-恢复性能增加,当阿拉伯木聚糖添加量大于10%时,面团流变性能变差;扫描电子显微镜显示,阿拉伯木聚糖添加量小于15%时,可以促使面团体系内淀粉颗粒聚集,当阿拉伯木聚糖大于15%时,淀粉聚集状态更加紧密,面筋的连续性遭到破坏;质构结果表明：随着阿拉伯木聚糖添加量的增加,面团黏性显著增加（p<0.05）,但当阿拉伯木聚糖添加量大于10%时,面团硬度、咀嚼性和弹性降低;此外,当阿拉伯木聚糖添加量为10%时,面包整体可接受度显著提高（p<0.05）。综上,在复合面包粉中添加10%的阿拉伯木聚糖,可以最大限度地增加面包中阿拉伯木聚糖的含量,同时又可以制得品质良好的面包。     

啤酒酿造过程中的阿拉伯木聚糖和果聚糖

可溶性膳食纤维在啤酒酿造中深受关注至少有两个原因。以前,酿酒商曾因为膳食纤维可能存在的提纯和过滤问题,会延长麦汁和啤酒的生产时间;另一方面,膳食纤维对结肠和消费者的整体健康状况具有有益的作用,是人们食用纤维中的可发酵部分。本文主要研究了啤酒酿造过程对麦芽、麦汁和啤酒中的可溶性膳食纤维含量的影响。阿拉伯木聚糖经酸性水解后使用高效阴离子交换色谱-脉冲安培检测法（HPAEC／PAD）进行测定。果聚糖经酶消化后测定,β-葡聚糖采用卡尔科弗卢尔荧光增白剂分析。麦芽和啤酒分析均按照中欧酿造分析委员会（MEBAK）和欧洲啤酒酿造公约（EBC）的标准执行。在麦芽制造过程中,水溶性阿拉伯木聚糖（WEAX）的含量迅速增加,而糖化和发酵过程对成品啤酒中的含量无明显影响。在被调查的大量谷物中,麦芽制备和麦汁生产过程对果聚糖的含量无影响,但在发酵过程中果聚糖的含量降到最初含量的10％。对来自不同酿酒厂的40种德国小麦啤酒样本分析显示,阿拉伯木聚糖含量可从0．87高达至2．88g/L,阿拉伯木聚糖含量与啤酒麦汁的最初浓度具有很大的相关性。在啤酒生产中,麦芽的使用量和谷物的质量是影响瓶装啤酒中阿拉伯木聚糖含量的重要因素。尽管果聚糖在麦汁中有一定的含量,但是在啤酒中的含量却微乎其微。阿拉伯木聚糖含量增高并没有造成麦汁和啤酒黏度的增加。     

小麦细胞壁结构的地理差异及水分调控作用

为了探讨小麦糊粉层细胞的细胞壁结构在不同产地的地理差异,以8个不同产区的小麦品种为研究对象,研究了小麦籽粒中糊粉层细胞壁厚度及其组分(阿拉伯木聚糖和β-葡聚糖)的含量和小麦籽粒体内水分子移动性。通过相关性分析和主成分分析研究了不同参数之间的相互关系,结果表明:在8个不同产区中,小麦籽粒糊粉层细胞壁厚度及其组分含量差异显著;小麦籽粒糊粉层细胞壁厚度与籽粒总阿拉伯木聚糖(Total arabinoxylan,TAX)含量呈极显著正相关性(r=0.931,P0.01),可通过测量TAX含量来比较小麦籽粒糊粉层细胞壁厚度;小麦籽粒糊粉层细胞壁厚度和TAX含量与海拔呈显著正相关(r=0.839,P0.01)。通过低场核磁共振分析发现糊粉层细胞壁结构对籽粒内的水分有一定的调控作用:在75%相对湿度下,糊粉层细胞壁越厚的小麦籽粒吸水量越少。     

阿拉伯木聚糖的氧化交联与啤酒大麦麦芽过滤性能的相关性研究

本文以18个大麦麦芽样品为研究对象,以pearson相关分析法研究了大麦麦芽中过氧化物酶(Peroxidase,POD)、麦汁中键合态阿魏酸以及多聚阿拉伯木聚糖(PAX)与麦芽过滤性能的相关性。研究结果表明:麦芽过滤速度与麦芽POD酶活、麦汁粘度、麦汁中键合态阿魏酸及PAX含量呈显著负相关,相关系数分别为0.632(p<0.01)、0.521(p<0.05)、0.555(p<0.05)和0.664(p<0.01);PAX含量与键合态阿魏酸含量、麦汁粘度呈显著正相关,相关系数分别为0.590(p<0.05)和0.595(p<0.01)。这一结果表明,阿魏酸介导的AX的氧化交联与大麦麦芽过滤性能紧密相关,很可能是AX导致麦芽过滤性能差的重要途径之一。本文为改善大麦麦芽过滤性能提供了一定的理论依据。      

啤酒中阿拉伯木聚糖的溶解、降解及堵塞膜机制的研究

阿拉伯木聚糖是谷物细胞壁中的一种非淀粉质多糖，在啤酒酿造过程中，阿拉伯木聚糖会造成浸出率降低、麦汁黏度升高、影响麦汁和啤酒过滤(尤其是纯生啤酒的膜过滤)、成品啤酒浑浊等。本文系统的研究了谷物中阿拉伯木聚糖的结构、理化性质和对酿造的影响；比较了气相色谱法和比色法测定阿拉伯木聚糖；报道了阿拉伯木聚糖在酿造过程中含量的变化，并以小麦和小麦芽为辅料，系统的研究了糖化温度、谷物粒径和料水比对阿拉木聚糖在糖化过程中溶解的影响；在热力学和动力学方程的基础上，建立了糖化过程中预测内切木聚糖酶和阿拉伯木聚糖的模型；通过电子显微镜手段表征了不同分子量阿拉伯木聚糖对膜过滤的影响；运用响应面分析法，采用木聚糖酶优化了酶解阿拉伯木聚糖的条件。     

Effects of arabinoxylan solubilization on wort viscosity and filtration when mashing with grist containing wheat and wheat malt

Arabinoxylans are partially water-extractable, high-molecular-weight polymers that contribute to the problems of viscosity and membrane filterability during beer brewing. These problems are more pronounced when wheat and wheat malt are used as adjuncts due to their higher arabinoxylan contents and higher molecular weights. This paper aimed at investigating the effects of mashing temperature, time, grist size and liquor:grist ratio on the solubilization of arabinoxylans. Results indicated that increasing the mashing temperature generally increased the amount of arabinoxylans released into the wort. When greater proportions of wheat or wheat malt were used as adjunct, higher arabinoxylan contents in the final wort were observed. The more finely ground the grist, the more were arabinoxylans released into the wort. When more diluted mashes were used, more efficient solubilization of arabinoxylans was observed. The effects of arabinoxylan content and β-glucan content on the wort viscosity were also examined using a General Linear Model (GLM). There was a good correlation (R² = 0.98) between wort viscosity and its arabinoxylan and β-glucan contents.     

Unmalted triticale cultivars as brewing adjuncts: effects of enzyme activities and composition on beer wort quality

The applicability of three selected triticale cultivars (Trinidad, Lamberto, Fidelio) for use as brewing adjuncts was investigated in comparison with wheat adjunct and barley malt. Fermentable substance, crude protein and arabinoxylan levels of starchy materials were determined as well as their native potencies (amylolytic, proteolytic, pentosolytic) to solubilise and degrade grain components during mashing. Laboratory‐scale experiments were performed to evaluate the influence of the adjuncts (composition, enzyme potency) on beer wort quality by mashing mixed (1:1) grists of malt and adjunct. Barley malt was rated as the superior raw material, possessing considerably higher enzyme activities and yielding the lowest wort viscosity. Among the triticale cultivars cv Trinidad was identified as the most suitable to serve as a brewing adjunct due to its improved starch solubilisation properties and its ability to generate low wort viscosities. Compared with the potent malt enzymes, the enzyme activities of unmalted triticale (such as amylases, pentosanases and proteases) had little affect on the composition of the sweet worts. In contrast, the contents of crude protein and fermentable substance of the triticale varieties greatly affected wort quality. Furthermore, the adjunct moiety determined the level of wort viscosity when mashing a combination of malt and triticale. In general, the brewing properties of triticale cv Trinidad were comparable with those of wheat. Copyright © 2004 Society of Chemical Industry     

COMPOSITION OF BREWING SYRUPS—A REVIEW

The composition of various syrups derived from barley, malt, maize and wheat and of worts prepared from them has been surveyed. Wider variations in the concentrations of fermentable carbohydrates occurred in these worts than in malt worts. Total nitrogen contents in the diluted barley and malt syrups examined were generally similar to those of wort. Certain amino acids were present in greater amounts in barley syrups than in wort but it is doubtful whether the differences are of practical significance. Only very limited information was found on the lipid, tannin and mineral contents of syrups.     

SMALL SCALE MASHING EXPERIMENTS WITH GRISTS CONTAINING HIGH PROPORTIONS OF RAW SORGHUM

Small scale mashes (50 g total grist) with grists containing high proportions of raw sorghum (50%–80% malt replacement) showed high values of extract recovery and produced worts of lower total nitrogen, free amino nitrogen, viscosity and colour but higher values of pH compared to worts produced from all malt mashes. Increasing the proportion of raw sorghum in the grist relative to malt resulted in a decline in extract recovery, wort total nitrogen, free amino nitrogen and an increase in wort pH. Addition of industrial enzyme preparations to mashes containing raw sorghum resulted in higher values of extract recovery (enzyme preparations containing α amylase and β glucanase), higher values of wort total nitrogen and free amino nitrogen (enzyme preparations containing a neutral proteinase) and decreased wort viscosity (enzyme preparations containing β glucanase or cellulases) compared to worts produced from untreated mashes. Worts and beers were produced on a pilot brewery scale from 50% malt and 50% polished (whole) sorghum (single decoction mashing regime) and 20% malt and 80% raw sorghum supplemented with an industrial enzyme preparation (double mashing regime). Mashes comprising 50% malt and 50% polished sorghum showed comparable wort filtration behaviour (lautering) to that of control mashes (70% malt and 30% maize grists) whereas wort produced from 20% malt and 80% raw sorghum filtered slowly. Worts produced from grists containing sorghum were of high fermentability and showed lower levels of total nitrogen and free amino nitrogen compared to control worts. Analysis of worts produced from small scale mashes containing raw sorghum and a pilot brewery scale mash comprising 20% malt and 80% raw sorghum demonstrated that the levels of total nitrogen and free amino nitrogen were higher than expected from the reduction in the malt content of the mash, consistent with the release of nitrogenous components (polypeptides, peptides and amino acids) derived from sorghum into the wort. Beers produced from 50% malt and 50% polished sorghum and 20% malt and 80% raw sorghum were filtered without difficulty and were of sound flavour. Beers produced from 50% malt and 50% polished sorghum contained lower levels of isobutanol, 2-methylbutanol, dimethylsulphide and higher levels of n propanol and diacetyl compared to control beers.     

Effect of kilning on the composition of protein and arabinoxylan in wheat malt

To explore the effect of kilning on the quality of wheat malt, wheat variety LM21 was malted with three different kilning programmes. Protein composition and arabinoxylan, xylanase (EC 3.2.1.8) activity, diastatic power and free amino nitrogen (FAN) were evaluated. Arabinoxylan content and xylanase activity were monitored during the kilning process. The results showed that the malt obtained from the kilning programme A showed the highest diastatic power, Kolbach index, FAN and lowest wort viscosity. Total arabinoxylan content showed no significant change during the kilning process, while the water extractable arabinoxylan and the xylanase activity reached the maximum values at the kilning temperature of 55°C, after which the xylanase activity decreased with the increase in kilning temperature. Extending kilning time at 40–50°C increased the diastatic power, FAN and Kolbach index and reduced the wort viscosity. © 2019 The Institute of Brewing & Distilling     

Changes in crude arabinoxylan during cloudy wheat beer brewing on a production scale

As one of the major non‐starch polysaccharides in the cloudy wheat beer, arabinoxylan has a crucial influence on the wort viscosity, foam profile and stability of the beer. In this study, the cloudy wheat beer was fermented on a production scale with a ratio of barley to wheat malt of 1:1, during which the changes in arabinoxylan were monitored in order to determine the key steps which influence the content, substitution degree of arabinoxylan (A/X) and average degree of polymerization (avDP) value of crude arabinoxylan during cloudy wheat beer brewing. The results show that the total contents of crude arabinoxylan, arabinose, xylose and galactose increased until the end of mashing and then dropped with the addition of spent grain sparging water. The crude arabinoxylan decreased during the saccharification, and then stabilized at ~10.00 mg/g. During fermentation and storage, the content of crude arabinoxylan did not change remarkably. The A/X remained at ~0.50 in the process of wort preparation and brewing and the avDP value of crude arabinoxylan decreased during saccharification and then stayed at ~3.00 in the fermentation and storage phases, which was lower because the contents of free arabinose, xylose and galactose were not subtracted from the total contents of the sugars. Therefore, wort preparation is shown the key step influencing the changes in crude arabinoxylan during cloudy wheat beer brewing. Copyright © 2017 The Institute of Brewing & Distilling     

Effects of Wheat Protein Content on Endosperm Composites and Malt Quality

In this study, the malting performance of six traditional Chinese wheat varieties was evaluated. The effects of protein content on wheat endosperm composition and the malt quality were studied. The β‐glucan in the malt showed a positive correlation (r = 0.806, P<0.1) with the protein content of the wheat. With an increase in protein content, there was a significant linear decrease in extract (r = ?0.923, P<0.01) and Kolbach Index (r = ?0.850, P<0.05), but diastatic power, soluble protein and FAN gave a peak value at 16.0% protein content. Because of the suitable protein and starch content, the malt qualities of wheat W‐3 were satisfactory. Extract was 81.7%, saccharification time was 6.5 min, diastatic power was 484.07WK, FAN was 136.58 mg/100 g, the Kolbach index was 40.0% and viscosity was 1.77 cP.     

不同蛋白质溶解度的小麦芽蛋白质组成及麦芽质量分析

为了研究小麦芽蛋白质溶解度与蛋白质组分及麦芽指标间的相关性,通过控制不同的浸麦度和发芽时间,制备了蛋白质溶解度分别为31.4％、33.1％、37.0％、37.6％、39.5％、40.9％、45.5％和54.2％的8种小麦芽,分析了小麦芽蛋白质组分、降解酶及麦芽基本指标.结果表明:随着小麦芽库值的增加,水溶性蛋白质含量成线性增加,醇溶性和碱溶性蛋白质呈现直线下降.小麦芽内肽酶活力与水溶性蛋白质含量、水分及浸出物呈现显著正相关(r分别为0.732、0.792和0.727),与醇溶性蛋白质含量呈现显著负相关(r=-0.734).因此小麦芽内肽酶活力的提高将有助于小麦芽浸出物的增加.小麦芽库值与水分、色度、浸出物、FAN、酸度均存在极显著正相关性(r=0.885、r=0.971、r=0.880、r=0.915和r=0.964);与浊度存在显著正相关(r=0.714);与有效酸度存在极显著负相关(r=-0.921).所以提高蛋白质溶解度小麦芽浸出物、浊度、FAN、酸度、色度等指标都会提高.比较8种小麦芽指标,蛋白质溶解度为39.5％时小麦芽指标较好.此时,浸出物为82.0％,FAN 166 mg/100 mg,糖化力为496 WK,黏度为1.61 cP,糖化时间为6 min.     

Effects of mashing on total phenolic contents and antioxidant activities of malts and worts

Effects of mashing on total phenolic contents (TPC), radical‐scavenging activity, reducing power and metal chelating activity of malts and corresponding worts were clarified in this study. Results showed that there were significant variations in TPC and antioxidant activity across malts and worts. An 8.8% of increase in TPC was observed during the early stage of mashing, accompanied by an increase in antioxidant activity. However, 2.6% of decrease in TPC and inconsistent changes in antioxidant activity were found during the mashing at higher temperature. Overall, mashing resulted in 6.0% and >10.0% of increases in TPC and antioxidant activity, respectively. Moreover, Pearson correlation analysis revealed that there were good correlations (ranging from 0.622 to 0.735, P < 0.01) between TPC and antioxidant activity of malts and worts. Additionally, mashing resulted in more positive correlations between TPC and antioxidant activity, emphasising the key role of malt phenolic compounds for wort antioxidant activity.     

Corn grist adjunct – application and influence on the brewing process and beer quality

In the brewing industry, barley malt is often partially replaced with adjuncts (unmalted barley, wheat, rice, sorghum and corn in different forms). It is crucial, however, to preserve constant quality in the beer to meet the expectations of consumers. In this work, how the addition of corn grist (10 and 20%) influences the quality of wort and beer was examined. The following parameters were analysed: wort colour, dimethyl sulphide (DMS) and protein content, non‐fermentable extract, extract drop during fermentation, alcohol content and the attenuation level of the beer, together with filtration performance. The samples (all‐malt, and adjunct at 10 and 20% corn grist) were industrial worts and the beers produced in a commercial brewery (3000 hL fermentation tanks). The application of 10 and 20% corn grist had an effect on the wort colour, making it slightly lighter (11.1 and 10.5°EBC, respectively) than the reference barley malt wort (12.2°EBC). The free amino nitrogen level, DMS and non‐fermentable extract were significantly lower in the worts produced with the adjunct; the alcohol content and attenuation levels were higher in the beers produced with adjunct. The use of corn grist, at the level of up to 20% of total load, appears to affect some of the technological aspects of wort and beer production, but it does not significantly influence the final product characteristics. Copyright © 2014 The Institute of Brewing & Distilling