啤酒大麦制麦过程中淀粉酶活性变化动态的研究

以不同品种的大麦为材料,运用底物分析法检测三种淀粉酶的活性。不同品种的大麦中α-淀粉酶、β-淀粉酶和极限糊精酶活力差异较大,因此实际生产中可对不同品种大麦进行筛选,选用酶活较高的大麦来制备麦芽;在制麦过程中,浸麦可在一定程度上抑制淀粉酶的活力;淀粉酶的总活力在发芽初期缓慢增加,2～3d后急剧增加至最大值;焙焦可使三种酶酶活有不同程度的下降。      

啤酒大麦制麦过程中淀粉酶活性变化动态的研究

以不同品种的大麦为材料,运用底物分析法检测三种淀粉酶的活性.不同品种的大麦中α-淀粉酶、β-淀粉酶和极限糊精酶活力差异较大,因此实际生产中可对不同品种大麦进行筛选,选用酶活较高的大麦来制备麦芽;在制麦过程中,浸麦可在一定程度上抑制淀粉酶的活力;淀粉酶的总活力在发芽初期缓慢增加,2～3d后急剧增加至最大值;焙焦可使三种酶酶活有不同程度的下降.     

制麦过程中添加金属离子与赤霉素对大麦发芽过程淀粉酶系影响的研究

大麦发芽过程中,添加不同浓度的金属离子Mg2+、Ca2+、Zn2+、K+、Na+和赤霉素(GA3)对α-淀粉酶、β-淀粉酶和极限糊精酶活性有一定的激活和抑制作用;实验发现,添加量分别为:Mg2+50mg/kg,Ca2+50mg/kg,Zn2+20mg/kg,K+60mg/kg,Na+80mg/kg,GA30.5mg/kg时,对上述3种淀粉酶酶活均有一定的激活作用。与单独用金属离子或赤霉素浸麦相比,金属离子和赤霉素的配合使用对3种淀粉酶的酶活提高作用更为显著。     

有机大麦发芽过程中淀粉酶的变化

本文研究了11种地方品种大麦（普通大麦）和相对应的麦芽。根据相同的合约,11种大麦在相同气候和土壤条件下种植。为了确定相同种植条件下的大麦样品在糖化过程中的酶活变化,所有试样测定了α-淀粉酶和β-淀粉酶的活力。另外,通过SDS—PAGE测定了发芽过程中蛋白质类型的改变。每个大麦试样的蛋白质含量、淀粉酶数量和质量之间都有差别,尽管通过sDS—PAGE分析Betamy1提取液（含β-淀粉酶）得到两个务带41-42kDa和55—58kDa,但由于仅仅55—58kDa带有差别,因此考虑只用它来评估大麦是否适合于啤     

大麦含氮量对制麦工艺的影响

我们对高含氮量和低含氮量大麦的制麦特性作了比较,结果表明低含氮量可促进发芽率和浸出物的提高,麦芽的溶解度与β-葡聚糖的含量无关。通常,高氮大麦和低氮大麦中的α-淀粉酶和β-淀粉酶活力不同,所以含氮量并不能准确表示出谷物生成淀粉水解酶的能力。     

小麦陈化过程中淀粉酶活力变化的研究

试验采用控制温度和湿度的人工陈化方法,促使小麦在温度为40℃、湿度100%的条件下加速陈化,并通过对陈化过程中小麦α-淀粉酶及总淀粉酶活力变化的测定,结合近几年粮食陈化机理的研究,探讨小麦中α-淀粉酶与总淀粉酶活性随陈化时间的变化规律。     

淀粉脱支酶的研究进展及应用

阐述了2种淀粉脱支酶的作用机理,简要综述了2种淀粉脱支酶的类型、研究历史及测定方法、对淀粉粒结构与品质的影响及应用前景。     

制麦过程中小麦淀粉含量及淀粉酶活力变化研究

以 6种小麦为试材 ,对制麦前后小麦直链、支链淀粉含量以及发芽过程中的α、β -淀粉酶活力的动态变化进行了研究 ;对成品麦芽中淀粉酶活、淀粉含量及成品麦芽特性之间的关系进行了分析。制麦前后各品种小麦支链、直链淀粉含量均下降 ,总淀粉降解程度与原小麦中支链、直链淀粉比存在正相关性 (P <0 .1)。成品麦芽中α、β -淀粉酶活与品种有关。成品麦芽糖化力与麦芽中淀粉酶活存在显著 (P <0 .0 5 )正相关性 ;成品麦芽糖化时间与麦芽淀粉含量存在极显著 (P <0 .0 1)正相关性。筛选出豫麦 5 0、SP2 0 2 7、pH97194 2为较好的制小麦麦芽品种     

麦芽品质性状标准和非标准检测方法的比较

本实验的目的是使用简单相关性来比较标准及非标准的麦芽品质性状检测方法,并用多元统计来分析9个标准和22个非标准的麦芽检测方法,以鉴别六个优质啤酒大麦品种。简单线性回归表明这些品种的α-淀粉酶、β-淀粉酶、极限糊精酶及α-葡萄糖苷酶的耐热性之间存在差异,与麦汁的渗透溶质浓度呈正相关性（r=-0．853～0．958,P≤0．05～0．01）,与糖化力相关（r=0．872～0．937,P≤0．05～0．01）。麦芽品质非标准性状的主成分分析（PCA）被认为比标准性状的主成分分析更有效,前者可以用最低实际发酵度对六棱和二棱品种进行区分,而实际发酵度是糖化性能的重要指标。六个优质啤酒大麦中的两个品种最显著的品质性状特征是α-葡萄糖苷酶、极限糊精酶及α-淀粉酶的活性最低,而这两种麦芽的α-淀粉酶、β-淀粉酶和极限糊精酶的耐热性以及它们的麦汁渗透溶质浓度却是最高的。     

酶法制备的玉米全淀粉β-极限糊精性质初步研究

玉米全淀粉糊化后直接经β-淀粉酶水解制得β-极限糊精。对β-极限糊精的颗粒形态、不同影响因素下的黏度特性进行了研究。结果表明，β-极限糊精颗粒表面光滑，但形貌不规则；增大浓度、添加蔗糖，β-极限糊精的黏度升高，但添加氯化钠、酸、碱，β-极限糊精黏度降低。     

利用(NH_4)_2SO_4分步盐析法从麦芽中初步分离极限糊精酶

文中对极限糊精酶的(NH4)2SO4盐析法进了研究。从大麦芽中萃取得到的粗酶液,采用(NH4)2SO4盐析法进行粗分级提取,绘制盐析曲线,确定盐析法纯化极限糊精酶的方案,并研究了各方案对极限糊精酶纯化纯度和得率的影响。研究结果表明:盐析曲线中饱和度分别为35%和80%时出现两个酶活峰,但80%饱和度时可以将绝大部分酶蛋白沉淀;分别采用一步法盐析(80%),二步法盐析(25%,80%),三步法盐析(25%,35%,80%)沉淀酶蛋白,其中三步法盐析可使极限糊精酶的纯度(A510/A280)达到1.635,纯化倍数和得率分别为8.8倍和49.5%,均优于其他两种方法。极限糊精酶盐析方案的优化可为其进一步分离纯化奠定基础。     

Variation in maltose in sweet wort from barley malt and rice adjuncts with differences in amylose structure

Starch from malt and solid adjuncts provides the majority of fermentable sugars for fermentation. However, there is no current data on the variation in starch structure (particularly long chained amylose) and its impact on the final wort composition of fermentable sugars, specifically maltose. This is the first study to report variation in amylose structure from barley malt and rice used as an adjunct and how this impacts the production of maltose. We compared four commercial malts with two rice adjuncts mashes, in solid and liquid additions, with an all‐malt mash used as a control. All combinations of malt and rice adjuncts were tested under two grist‐to‐liquor (G:L) ratios (1:3 and 1:4) in a 65°C ramped mash. After mashing, the wort original gravity and maltose concentration were measured. The commercial malts had different malt quality but very similar gelatinisation temperatures (~65°C). The malts varied in starch and amylose contents but had only minor variations in average amylose chain lengths. The two rice adjuncts also had similar average amylose chains lengths, but quite different amylose contents, and hence different gelatinisation temperatures. The results showed that liquid adjunct mashes had higher original gravity and maltose concentration for both G:L ratios. However, there was no consistent result in original gravity or maltose between G:L ratio or adjunct type, suggesting interactions between each malt and rice adjunct. Knowing amylose chain length could improve understanding of the potential maltose levels of the sweet wort prior to fermentation. © 2018 The Institute of Brewing & Distilling     

DIASTATIC POWER IN MALTED BARLEY: CONTRIBUTIONS OF MALT PARAMETERS TO ITS DEVELOPMENT AND THE POTENTIAL OF BARLEY GRAIN BETA-AMYLASE TO PREDICT MALT DIASTATIC POWER*

The malt parameters alpha-amylase, beta-amylase, limit dextrinase, protein and beta-glucan were each linearly related to the diastatic power measured in malted barley, with beta-amylase having the highest coefficient of variation (r² = 0.63). Multivariate regression analysis derived a model comprising beta-amylase, alpna-amylase and limit dextrinase, with no significant interactions (p < 0.05). The model accounted for over 79% of the variation in diastatic power. These three malt parameters might be usefully targeted in breeding programs aiming to improve diastatic power in malted barley. The analysis of samples from two harvests showed that malt diastatic power is also significantly related to total grain beta-amylase activity (r² ranging up to 0.61). This suggests that total grain beta-amylase can be used as a screening procedure for the diastatic power of experimental barley breeding lines. However the relationship is subject to significant genotypic (cultivar) and environmental influences (p < 0.001) and regression analysis found that diastatic power was significantly related to beta-amylase and cultivar (r² = 0.76). Thus the use of a single regression curve comprising pooled data from several cultivars to relate diastatic power and total grain beta-amylase might be misleading. For barley breeding programs, the most effective use of the beta-amylase model as a criterion to identify experimental lines with unacceptable diastatic powers is to apply as a benchmark the total grain beta-amylase activity of a reference variety at each location, accepting lines with consistently higher beta-amylase activities for micromalting and further testing.     

麦芽极限糊精酶提取工艺的优化研究

本文研究麦芽极限糊精酶提取的最佳工艺条件,采用单因素分析、多元二次回归、Box-Behnken中心组合实验建立数学模型及采用响应面分析法获得了酶提取的最优工艺参数为:液料比4.25、温度45℃、pH值5.4、时间17.4h、还原剂用量21.4mmol/L。     

麦芽搭配及淀粉酶系活力对麦汁糖组分的影响

分析了不同产地(加拿大、澳大利亚)、不同品种(Metcalfe、Copeland、Hind marsh、Bass、Baudin、Scope、Gairdner)麦芽淀粉酶系活力,发现加拿大麦芽淀粉酶活力普遍高于澳大利亚麦芽,且品种间存在显著差异;通过研究麦芽淀粉酶系活力与常规指标的关系,发现常规指标糖化力与β-淀粉酶与极限糊精酶活力存在显著相关性;其次,将酶系活力差异较大的麦芽按照不同比例进行搭配,分析搭配前后酶活力变化,发现搭配后3种酶活实际值均高于按比例计算的理论值,表明麦芽搭配具有协同作用;为进一步研究淀粉酶活力对麦汁糖组分的影响,模拟大生产含辅料的糖化工艺进行麦汁制备,分析配方麦芽淀粉酶活力与麦汁糖组成的关系,发现影响麦汁极限发酵度、可发酵性糖比例的关键酶为极限糊精酶。     

ICP-AES分析植酸酶对制麦过程中游离态金属离子含量的变化

运用电感耦合等离子体原子发射光谱法(ICP-AES)考察了外源添加植酸酶对大麦发芽过程中游离态K+、Na+、Ca2+、Mg2+、Zn2+含量的变化。实验发现:添加外源植酸酶能提高发芽过程中游离态金属离子的含量,K+、Na+、Ca2+、Mg2+、Zn2+含量同比可提高10.7%、23.4%、16.3%、8.0%、75.5%。通过比较金属离子含量的变化可以为制定合理的制麦工艺提供参考。     

大麦芽极限糊精酶的分离纯化及酶学特性分析

将大麦芽提取的极限糊精酶粗酶液,利用硫酸铵沉淀、离子交换层析和凝胶过滤色谱等分离方法对极限糊精酶进行逐步分离纯化。结果表明：纯化倍数为31.23,回收率为8.81%。经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳后,图谱显示样品具有较高的纯度,分子质量约为97kD。同时研究了纯化前后极限糊精酶在不同作用环境下酶的活性变化,发现纯化后样品在温度45℃和pH 5.5左右具有最大酶活性,与粗酶液中酶活性相比具有明显差异。在体系中添加不同浓度的金属离子,结果发现,Mg2+、Ca2+、Mn2+在浓度较低时,对酶活性具有激活作用,而浓度较高时,则具有抑制作用;整体上,K+对酶活性影响不大;Zn2+、Fe2+对酶活性具有抑制作用。     

Changes in malt quality during production in two commercial malt houses

This investigation presents a holistic and comprehensive assessment of the stepwise changes in barley quality during the malting process for multiple batches of two Australian malting varieties (Buloke and Gairdner), in two modern, commercial scale pneumatic malthouses. The study sought to analyse and compare malting plant and variety with respect to basic changes in malt quality for protein (total protein and free amino nitrogen), fermentability (apparent attenuation limit and diastatic power), extract yield, along with filtration indicators (lautering efficiency, viscosity and β-glucan). Overall, comparing the two malt plants, it was observed that although malt batches and varieties followed different malting pathways, the finished and kilned malt  was of satisfactory quality in terms of FAN, viscosity, friability, fermentability and extract. © 2020 The Institute of Brewing & Distilling