有色特种麦芽

有色特种麦芽赋予啤酒特征性的色度和风味,其应用满足了消费者对不同风味啤酒的需求,论述了有色特种麦芽的种类,风味特征及生产的啤酒风味特征,阐明了其焙烤工艺,成品有色麦芽的分析指标和在啤酒中的应用.     

特种麦芽及其对啤酒特性的影响综述

啤酒是世界上广受欢迎的酒精饮料。随着经济收入增加和生活水平的提高,消费者对于啤酒品质的追求也在提高,除了常见的商业啤酒以外,各式各样独具特色的精酿啤酒逐渐被人们所熟知。随着精酿啤酒在全球兴起,特种麦芽日益成为了新的研究热点。特种麦芽通常用于改善啤酒的风味、香气以及色泽,丰富啤酒的多样性。因此,文章将从特种麦芽制麦过程、特种麦芽风味成分以及特种麦芽对啤酒特性的影响3个方面进行综述,以期为后续的特种麦芽及其对啤酒特性影响的研究提供帮助。     

啤酒“麦芽香”特征及其风味物质的研究

研究麦芽风味特征的感官品评,分析麦芽和啤酒中9种美拉德风味物质含量范围及其对啤酒风味影响,探讨酿造过程9种风味物质的变化规律及其机理。研究重构了麦芽风味特征感官品评描述语言体系,将"麦芽香"特征具象化为7大类麦芽风味;发现麦芽中9种麦芽美拉德风味物质含量与麦芽焙烤强度有一定正相关,但在高温焙烤工艺麦芽生产中不同风味物质的产生受焙烤阶段温度、时间、麦芽水分等因素影响较大;深色啤酒中9种风味物质含量运高于淡色啤酒,但在多数样品中含量仍低于相应口味阈值,仅部分样品中麦芽酚和菠萝酮含量高于阈值;仅甲基吡嗪类物质含量与深色啤酒的重度焙烤味和整体麦芽香气强度有强正相关性;这些风味物质并非全部直接来自麦芽,其含量在啤酒酿造过程仍发生较大变化。     

着色特种麦芽形成机理与生产工艺的探讨

经过分析研究，设计了两套着色特种麦芽的生产工艺流程。方案一生产出来的麦芽色泽黄褐，香味较浓，适合生产棕色、深红色，口感醇厚，麦芽香味较浓的略有甜味的风味啤酒；方案二生产的特种麦芽，色泽深黑，香味浓郁，适合酿造深黑色啤酒，并非常有利于啤酒非生物稳定性。     

麦芽褐变程度对脂肪酸氧化酶活性的影响

浅色啤酒风味稳定性的改变通常是由于在糖化过程中脂肪酸氧化酶催化脂质降解的申间产物的氧化反应引起的。本文研究了不同褐变程度的麦芽时脂肪酸氧化酶活性的影响。研究结果表明，脂肪酸氧化酶活性只存在于浅色麦芽中，受高于63℃的糖化温度和特种麦芽中关拉德反应产物的影响。尤其是，当浅色麦芽中添加特种麦芽时．能够强烈抑制脂肪酸氧化酶的活力、降低着色潜力．可以有效地降低浅色啤酒老化风味的出现。     

基于挥发性风味物质的啤酒焙烤麦芽制麦工艺研究

啤酒焙烤麦芽是重要的工坊啤酒酿造原料,其含有的醛类、呋喃类和吡嗪类等挥发性风味物质会直接影响啤酒质量和风格。本文筛选出适合分析焙烤麦芽挥发性风味物质的色谱柱,调整焙烤强度和预糖化时间制备出系列焙烤麦芽,通过分析其挥发性风味物质的组成、相对含量、麦汁色度和品评差异,研究影响焙烤麦芽挥发性风味物质的因素并识别关键制麦工艺控制点。结果表明,DB-Waxetr极性色谱柱分离呋喃类和吡嗪类化合物效果佳,比HP-5ms非极性色谱柱更适合分析焙烤麦芽;温度是影响焙烤干麦芽质量的重要因素,不同温度下焙烤产生的各类挥发性风味物质可带来差异化的风味特征;制备结晶麦芽的重点是促进呋喃类生成,工艺关键在于确保良好的预糖化及控制合适的焙烤温度;挥发性风味物质组成和含量对焙烤麦芽的质量有重要指示作用,了解其在各工艺条件下的变化趋势,有利于制备质量稳定、色度和风味特征符合预期及品评口感协调的优质焙烤麦芽。     

结晶麦芽的制备工艺优化及其品质分析

结晶麦芽作为重要的特种麦芽,可以赋予啤酒多样的风味和独特的口感。该文选取不同发芽时间的绿麦芽为原料,比较糖化后还原糖和游离氨基氮含量的变化,确定用于制备结晶麦芽的绿麦芽,优化绿麦芽的预糖化与焙焦工艺,制备结晶麦芽,并分析其常规理化指标与风味特征。结果表明,选择发芽84 h的绿麦芽为原料,调节预糖化水的pH值为3.36,蛋白质休止温度为60℃,糖化温度为71.1℃,预糖化结束的绿麦芽游离氨基氮与还原糖含量分别达到142.4 mg/L与26.2 g/L。由此制备的结晶麦芽结晶率98%,且麦芽内部结晶均匀,风味物质含量达到1 265μg/L,比普通商品结晶麦芽提高了98.3%,主要风味物质为醛类。该研究为国产优质结晶麦芽的规模化生产奠定了基础。     

特种麦芽风味化学的研究

本文综述了特种麦芽中风味物质形成的机理;讨论了特种麦芽中主要风味物质的物化性质,论述了特种麦芽中风味物质的提取和分析方法。     

精酿啤酒专用麦芽的研究进展

在工业啤酒日趋饱和的大背景下,精酿啤酒在中国受到越来越多消费者的喜爱,并呈现出广阔的成长空间。麦芽作为精酿啤酒重要原料之一,其品质优劣决定了啤酒品质的好坏。该文结合当前精酿啤酒专用麦芽的应用研究,总结、归纳了精酿啤酒酿造用麦芽的基本种类、制麦工艺、麦芽风味物质及麦芽主要成分对啤酒品质的影响,最后阐述了精酿啤酒专用麦芽对麦芽加工工业和精酿啤酒制造业的重要意义,并对精酿啤酒专用麦芽的前景进行了展望。     

啤酒的酒花香和麦芽香

酒花香和麦芽香无疑是啤酒感官指标中非常重要的风味指标，它们决定着啤酒的风味质量。从啤酒风味上讲，优质啤酒往往带有明显的酒花香或麦芽香。酒花香气清新，麦芽香气宜人，它们均能使啤酒消费者饮用啤酒后产生再次饮用的欲望。所以如何生产带有酒花香或麦芽香的啤酒应该是啤酒科技工作者的研究课题。近几年我们将“风味圈理论”与啤酒中风味物质的性质和风味特点结合起来进行了一些研究。现就一些简单内容及啤酒的酒花香和麦芽香的性质作一简单叙述。     

Impact of colour adjustment on flavour stability of pale lager beers with a range of distinct colouring agents

The impact of colour adjustment on the flavour stability of five pale lager beers with a range of colouring agents such as specialty malts, colouring beer and artificial caramel colourant was investigated. The research focused on determination of the endogenous anti-oxidative potential (EAP) of the beer samples using a novel Electron Spin Resonance (ESR) method. The results were correlated with the concentration levels of a portfolio of compounds formed during beer ageing, which were detected and quantified by GC–MS. The beer samples were also assessed by the ICBD sensory panel. Additionally, the quantification of organic radicals of the specialty malts and the roasted barley were conducted by ESR (whole intact kernel and milling fraction measurement). Based on the results of this holistic approach, a colouring agent was identified that enhanced the flavour stability of pale lagers based on the final beer’s physical-, chemical-, and sensory-properties.     

Aging characteristics of different beer types

Eight commercial beers (3 lager beers, 2 dark ales and 3 high-alcoholic ales) were aged for one year under normal storage conditions, and the changes with time of flavour profile and the concentration of 15 volatile compounds were monitored. The compounds were chosen as markers to evaluate the importance of different reactions in the aging process of each beer type. The development of typical aging flavours during beer storage could be linked to the Maillard reaction, the formation of linear aldehydes, ester formation, ester degradation, acetal formation, etherification and the degradation of hop bitter compounds. A difference in the nature of aging flavours between lager and specialty beers was found and seemed to be mainly the result of an increased Maillard reaction in specialty beers. Based on the results, some practical strategies are proposed to improve the flavour stability, depending on the beer type.     

原料对麦汁酚酸抗氧化能力的影响

本文检测了不同啤酒麦芽及酒花品种中酚酸的含量,分析了酿造原料对麦汁抗氧化能力的影响。结果发现,加麦、澳麦、国产西北三种麦芽中,澳麦提供的抗氧化能力较小,同时提供的老化物质也最少,对提高啤酒的风味稳定性有利。以单位α-酸计,香花比苦花提供更多的酚酸和抗氧化能力。酒花老化过程损失相当多的酚酸,酿造过程中应尽量使用新鲜的酒花。     

Foam inhibitors from specialty malts

Although there are product‐to‐product differences, the majority of the crystal and caramel malts tested have been shown to have a net destabilizing impact on foam. A foaming test using a model beer has been developed to quantify the magnitude of this inhibitory effect. Lipid analysis using thin‐layer chromatography reveals that there are elevated levels of triglycerides in problematic malts. There also appear to be oxidized lipids in the specialty malts, probably produced in the heating stage of malt production with higher levels in more intensely heated products. However some specialty malts, such as black malt, while containing such foam‐negative entities, do display superior foaming properties, probably because they develop even more powerful foam‐positive components in the severe heating events. Copyright © 2014 The Institute of Brewing & Distilling     

Sensory and Instrumental Flavour Analysis of Wort Brewed with Dark Specialty Malts

In order to explore the flavour produced by dark specialty malts, wort samples were brewed with different malts and evaluated by sensory and instrumental analysis. With increasing wort colour, a trained tasting panel detected more intense bitter and burnt flavours, whereas sweet and husky flavour notes decreased. Conversely, caramel and bread‐like flavour attributes had a maximal intensity for the intermediate wort colours. Tasting of 20 EBC worts indicated that the flavour profile was significantly affected not only by malt level and malt colour but also by malt origin. Furthermore, the darkest caramel malt (480 EBC units) was found to contain most Maillard aldehydes as determined by the reaction with thiobarbituric acid. Similarly, other intermediate products of the Maillard reaction such as acetic acid, diacetyl and 2,3‐pentanedione were found to arise in a higher concentration in dark caramel malts (220–480 EBC units) than in roasted malt (1200 EBC units). Dynamic headspace GC/MS further revealed that brewing with dark specialty malts considerably increased the level of 3‐methylbutanal, its aldol condensation product (2‐isopropyl‐5‐methyl‐2‐hexenal) and heterocyclic Maillard compounds. In contrast, dark malts drastically reduced the amount of hexanal in wort. By means of HPLC, it was established that only extreme roasting temperatures lead to the thermal degradation of ferulic acid to 4‐vinylguaiacol in malt.     

啤酒酵母的基因改良研究动态

近年来 ,利用基因工程进行酵母的育种在发酵广谱碳水化合物、提高糖化效率 ,改良酵母凝聚特性和改善啤酒风味方面取得了很大成绩。基因重组菌株将逐步应用到生产实践中。     

Impact of Dark Specialty Malts on Extract Composition and Wort Fermentation

Dark specialty malts are important ingredients for the production of several beer styles. These malts not only impart colour, flavour and antioxidative activity to wort and beer, they also affect the course of wort fermentations and the production of flavour‐active yeast metabolites. The application of considerable levels of dark malt was found to lower the attenuation, mainly as a result of lower levels of fermentable sugars and amino acids in dark wort samples. In fact, from the darkest caramel malts and from roasted malts, practically no fermentable material can be hydrolysed by pilsner malt enzymes during mashing. Compared to wort brewed with 50% pilsner malt and 50% dark caramel malt or roasted malt, wort brewed with 100% pilsner malt contained nearly twice as much fermentable sugars and amino acids. Reduced levels of yeast nutrients also lowered the fermentation rate, ranging from 1.7°P/day for the reference pilsner wort of 9 EBC to 1.1°P/day for the darkest wort (890 EBC units), brewed with 50% roasted malt. This additionally indicates that lower attenuation values for dark wort are partially due to the inhibitory effects of Maillard compounds on yeast metabolism. The application of dark caramel or roasted malts further led to elevated levels of the vicinal diketones diacetyl and 2,3‐pentanedione. Only large levels of roasted malt gave rise to two significant diacetyl peaks during fermentation. The level of ethyl acetate in beer was inversely related to colour, whereas the level of isoamyl acetate appeared to be affected by the use of roasted malt. With large levels of this malt type, negligible isoamyl acetate was generated during fermentation.     

Current Developments in Malting and Brewing Trials with Sorghum in Nigeria: A Review

Initially, large‐scale lager beer brewing with sorghum malts proved highly intractable due to a number of biochemical problems including: high malting losses estimated at 10–30% as against 8–10% for barley; high gelatinisation temperatures which limited starch solubilisation/ hydrolysis by the amylolytic enzymes during mashing; low extract yield/low diastatic power (DP) due to inadequate hydrolytic enzyme activities especially β‐amylase; low free α‐amino nitrogen (FAN) due to inadequate proteolysis limiting yeast growth during fermentation; high wort viscosities/beer filtration problems due to low endo‐β‐1,3; 1–4‐glucanase activities on the endosperm cell walls causing the release of some β‐glucans. Strident research efforts using improved Nigerian sorghum malt varieties (SK5912, KSV8 and ICSV400) have reported some encouraging results. The knowledge of the biochemical integrity of the endo‐β‐glucanases of the sorghum malt is helping to elucidate their mode of activity in the depolymerisation of the β‐glucans. This is bound to ensure process efficiency in sorghum beer brewing, reduce beer production costs and ultimately, produce a Pilsner‐type of lager beer with 100% sorghum malt.     

MALTING AND BREWING WITH BARLEYS HAVING BLUE ALEURONES

Blue aleurones in barley are associated with elevated levels of polyphenolic materials such as anthocyanins and anthocyanidins. A rapid method has been developed for assessing the anthocyanin content of barleys, malts and worts. Malts were prepared from a range of barleys, some of which had intensely blue aleurones, while others were only slightly blue or showed no visible pigmentation. The malting quality of barley was not affected by aleurone colour and ales and lagers of sound flavour as well as acceptable analytical parameters were brewed from malts having pronounced blue aleurones. In some cases sweet worts prepared from blue aleurone malts had a slight pinkish tinge, but this disappeared during wort boiling, and beer colours were normal. Levels of anthocyanins in barley correlated with those in malt and in wort. However, the concentration of anthocyanins was unrelated to the amount of anthocyanogens or total polyphenols. High anthocyanin levels in either barley or beer had no deleterious effects on beer flavour or the rate of haze development.