国麦甘啤三号制麦工艺的研究

本文介绍了甘啤3号的制麦特性和工艺，及在劳斯曼生产线上的表现，成品麦芽与KA4B麦芽的比较。     

制麦过程中大麦β-葡聚糖的变化及对麦汁和啤酒中β-葡聚糖含量的影响

观察制麦过程中大麦β-葡聚糖溶解度的变化,研究糖化条件对麦汁和啤酒中β-葡聚糖含量的影响。发芽4～5天后,绿麦芽中可溶性β-葡聚糖部分显著提高。然而,如果麦芽的内源性酶活经加热处理后被抑制,发芽前3天β葡聚糖的溶解一直增加,在之后的阶段开始降低。当提取温度从室温提高到45℃时,可溶性β-葡聚糖部分显著增加。溶解良好和溶解不良的麦芽在不同糖化温度下随着温度从45℃增加到75℃,麦汁中可溶性β-葡聚糖数量增加并最终在啤酒中残留。在任何温度下,由溶解不良麦芽所得麦汁和啤酒中的β-葡聚糖含量都非常高。甚至在低糖化温度下内源性酶也难以完全溶解这些葡聚糖。     

制麦工艺对燕麦麦芽营养品质的影响

以我国裸燕麦为研究对象,以燕麦在发芽前后植酸质量分数、β-葡聚糖质量分数及蛋白质体外消化率为考察指标,通过单因素和正交试验,研究浸麦温度(11～19℃)、发芽温度(11～19℃)及发芽时间(2～6d)对上述营养指标的影响。结果表明,浸麦温度对植酸质量分数、β-葡聚糖质量分数及蛋白质体外消化率没有显著影响,而发芽时间越长、发芽温度越高,燕麦中植酸和β-葡聚糖质量分数则越低;蛋白质体外消化率随着发芽时间的延长而升高,发芽温度对其影响不显著。通过优化试验得出的最佳制麦工艺:采用浸麦工艺(浸麦6h→休止10h→浸麦4h→休止7h→浸麦3h→休止1h),浸麦温度14℃进行浸麦,15℃发芽4d。在此条件下制麦燕麦中植酸质量分数下降了42.8%,而蛋白质消化率上升了142.1%,燕麦的营养品质有所改善。     

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。     

四氢嘧啶对冷冻面团的保护作用研究

目的 探究四氢嘧啶对冷冻面团的保护作用。方法 以添加四氢嘧啶和未添加四氢嘧啶面团为研究对象,置于-20℃冰箱冷冻0、15、30、60 d,探究酵母菌存活率、酵母菌发酵力、面团比容、水分含量、可冻结水含量和面团二级结构随冷冻时间的变化。结果 在冷冻过程中添加四氢嘧啶面团各指标均优于未添加四氢嘧啶面团,且整体变化趋势较平缓。在冷冻环境下,四氢嘧啶与面团中的水及蛋白质之间发生相互作用,从而抑制冰晶对酵母菌及面筋蛋白的伤害,使面团结构更稳定。结论 四氢嘧啶对冷冻面团中酵母菌活性和面筋蛋白同时起到保护作用且性质稳定,可将其作为一种新型抗冻剂用于冷冻面团生产中,同时也为四氢嘧啶潜在的食品领域应用提供理论基础。     

国产垦啤-2号大麦制麦酶系的影响因素

以垦啤 2号大麦(适合东北气候、土质种植)为原料,将酶活分析方法与传统制麦方法相结合,按照最佳制麦工艺所得成品麦芽各项指标均介于一级品与优级品之间,其中,糖化力、糖化时间、α 氨基氮、可溶性氮均优于优级品.通过研究制麦过程中各种添加剂对绿麦芽酶活的影响表明,利用体积分数0.1%甲醛浸麦1h效果较好;同样条件下,较质量分数0.9%NaOH浸麦,制麦酶系都有所提高.     

制麦工艺对SN1391小麦麦芽质量的影响

以小麦SN1391为试材,采用三因素三水平正交实验设计,研究浸麦度（40%～48%）、发芽温度（12～20℃）及焙焦温度（78～83℃）对麦芽质量的影响。通过对成品麦芽指标的分析,发现浸出物含量受制麦工艺参数影响不大;糖化力、糖化时间、α-AN含量、库尔巴哈值、麦芽β-葡聚糖含量、麦汁粘度受工艺参数影响较大;提高浸麦度与发芽温度,降低焙焦温度可以降低成品麦芽中β-葡聚糖的含量和麦汁粘度。以糖化力为主要指标时,对糖化力影响的主次因素顺序为:发芽温度>浸麦度>焙焦温度;得到最佳制麦工艺参数为:浸麦度47%～48%、发芽温度为18～20℃、焙焦温度为80～81℃。      

调整制麦工艺改善麦芽质量

本文针对一批滤速不好的麦芽，分析其理化指标，研究制麦工艺对成品麦芽质量的影响，调整制麦工艺，最终使该批大麦生产的麦芽质量得到了很大改善。     

代谢工程改造谷氨酸棒杆菌合成四氢嘧啶

为了获得四氢嘧啶生产菌株并利用此菌株提高四氢嘧啶产量,以谷氨酸棒杆菌（Corynebacterium glutamicum）野生菌株ATCC13032为研究对象,以赖氨酸积累量为评价指标,强化了天冬氨酸-β-半醛合成代谢流;通过阻断赖氨酸输出通道LysE,表达不同来源的四氢嘧啶操纵子ectABC,获得了四氢嘧啶生产菌株;通过强化天冬氨酸转氨酶和还原型烟酰胺腺嘌呤二核苷酸磷酸（NADPH）再生途径,进一步提高四氢嘧啶产量。结果表明,构建了一株高产赖氨酸的谷氨酸棒杆菌工程菌株LYS-3,赖氨酸积累量为28.48 g/L;表达操纵子HEectABC的谷氨酸棒杆菌ECT-3四氢嘧啶产量达到17.21 g/L;过表达基因aspC和ECpntAB谷氨酸棒杆菌ECT-6,摇瓶发酵四氢嘧啶产量达到21.85 g/L。研究结果可为天冬氨酸-β-半醛衍生物的生物合成提供参考。     

制麦条件对大麦发芽过程中β-葡聚糖含量及β-葡聚糖酶变化的影响

本文对大麦发芽时,麦芽中β-葡聚糖酶的产生和β-葡聚糖降解的多种因素进行了试验分析。结果发现,在发芽时控制低温有利于β-葡聚糖酶的生成和β-葡聚糖酶的降解;浸麦水的pH在中性和偏酸性条件下有利于β-葡聚糖酶的产生,但是在pH中性和偏碱性条件下有利于β-葡聚糖的降解;镁离子,锌离子,钾离子和钠离子有助于β-葡聚糖酶的生成及β-葡聚糖的分解;铜离子会抑制β-葡聚糖酶活性及β-葡聚糖的降解。     

Metabolite profiling of barley: Influence of the malting process

A metabolite profiling approach based on gas chromatography–mass spectrometry (GC/MS) was used to investigate time-dependent metabolic changes in the course of the malting process of barley. Barley grains were subjected to a micro-malting procedure involving steeping, germination and kiln-drying. Samples taken in the course of the malting process were subjected to an extraction and fractionation procedure covering a broad spectrum of lipophilic (e.g. fatty acid methyl esters, hydrocarbons, fatty alcohols, sterols) and hydrophilic (e.g. sugars, acids, amino acids, amines) low molecular weight barley constituents. Investigation of the obtained fractions by GC resulted in the detection of 587 distinct peaks of which 173 were identified by means of MS. Statistical assessment of the data via principal component analysis demonstrated that the metabolic changes during the malting progress are reflected by time-dependent shifts of the scores. Analysis of the corresponding loadings showed that polar metabolites were the major contributors to the malting time-driven changes in the metabolic profiles. Quantifications based on standardised peak heights revealed dynamic changes of the metabolites in the course of the different malting stages.     

大麦品种和制麦过程对麦芽含脂量的影响

脂类物质影响啤酒泡沫稳定性并对啤酒老化有重要作用.啤酒中脂类物质的浓度和性质取决于原料的组成和酿造过程.本文研究了大麦品种和制麦过程对麦芽含脂量的影响.采用意大利的四种春大麦和一种冬大麦作为样品,进行微型制麦和分析.本研究旨在确认大麦品种对麦芽含脂量及制麦过程中脂肪酸（FA）含量变化的影响.采用主成分分析（PCA）建立不同样品之间的关系,同样也对大麦的含脂量和制得麦芽品质的相关性进行了评估.数据显示制麦过程中大麦转化为麦芽时总脂含量显著下降;不同大麦品种的脂肪酸含量和脂肪酸图谱均不同.大麦含脂量和制得麦芽质量的相关性确认了脂类的负面影响.     

Influence of barley variety and malting process on lipid content of malt

The lipid content of a beer affects its ability to form a stable head of foam and plays an important role in beer staling. The concentration and the quality of lipids in beer depend on their composition in the raw materials and on the brewing process and they may exert considerable influence on beer quality. This paper presents an investigation of the influence of barley variety and malting process on the lipid content of finished malt. Five barley samples, grown in Italy, representing 4 spring barley and 1 winter barley were used. The samples were micro-malted and analysed. The aim of this research was to verify the influence of different barley varieties on the lipid content of malt and also on the changes in fatty acid (FA) profile during the malting process. Lipid content and FA profile were evaluated. Principal component analysis (PCA) was used to establish relationships between the different samples. An evaluation of the correlation between lipid content of barleys and the quality of the resulting malts was also conducted. The data showed that the total lipid content during the malting process decreased significantly as barley was converted into malt. Different barley varieties present different FA contents and different FA patterns. The correlation between the lipid content of barley and the quality of the resulting malt confirmed the negative influence of lipids.     

大麦发芽过程中蛋白质组的变化研究

通过双向电泳技术监测大麦发芽过程中水溶蛋白质组的变化,明确大麦发芽过程中蛋白质组的变化规律,为麦芽制造提供一定理论依据。以澳麦\     

制麦过程大麦和麦芽中麦角甾醇和呕吐毒素含量的变化

本文测定了不同品种大麦和麦芽中的呕吐毒素和麦角甾醇含量,共分析了20个大麦和20个麦芽样品,用正己烷溶解谷物中的碱性水解提取物以获得麦角甾醇,用乙腈/水及固相萃取(SPE)法提取呕吐毒素,通过配有紫外检测器的高效液相色谱(麦角甾醇)和质谱(呕吐毒素)进行检测。分析了制麦过程对两种化合物的影响,其中大麦中麦角甾醇浓度为0.88～15.87mg/kg,麦芽中的浓度为2.63～34.96mg/kg,比制麦增加了95%。因此,制麦过程对麦角甾醇浓度的影响很大(P=0.07);同时发现大麦中呕吐毒素浓度最大为641μg/kg,麦芽中为499μg/kg,没有发现制麦过程对呕吐毒素生成有影响,而且麦角甾醇和呕吐毒素间的相关性非常低(大麦为0.02,麦芽为0.01),因此麦角甾醇含量不能作为呕吐毒素污染的一个指标。     

Influence of barley malting operating parameters on T-2 and HT-2 toxinogenesis of Fusarium langsethiae,a worrying contaminant of malting barley in Europe

The fungus Fusarium langsethiae, exclusively described in Europe at present, seems to have taken the place of other Fusarium species in barley fields over the last 5 years. It has proved to be a highly toxic type-A trichothecene producer (T-2 and HT-2 toxins). The aim of this work was to study the ecotoxinogenesis of this fungus the better to identify and manage the health risk it may pose during the beer manufacturing process. The influence of temperature and water activity on its growth rate and production of toxins are particularly assessed from a macroscopic point of view. Different cultures were grown on sterilized rehydrated barley with a water activity between 0.630 and 0.997 and a temperature ranging from 5 to 35°C. Biomass specific to F. langsethiae and T-2 and HT-2 toxins were quantified by real-time polymerase chain reaction and liquid chromatography-mass spectrometry, respectively. It appears that the optimal temperature and water activity for F. langsethiae toxinogenesis are 28°C and 0.997. This fungus was able to produce 2.22 g kg^?1 of these toxins in 16 days on barley in optimal production conditions. The malting process seems to be a critical step because, in its temperature range, specific production was six times higher than under optimal temperatures for fungus growth. In the short-term, this work will help redefine the process conditions for malting. In the medium-term, the results will contribute to the development of a molecular tool to diagnose the presence of this contaminant and the detection of the toxins in barley, from fields to the end product.     

Monitoring of malting process by characterization of glycation of barley protein Z

Glycation is a common form of non-enzymatic modification that influences the properties of proteins. Although occurrence of protein glycation in food is known for several years, qualitative and quantitative analysis of its reaction products is still a challenging task. Our attention was focused on monitoring of changes in the glycation degree of protein Z, one of the most important protein components of barley malt that influences the properties of beer. The modification during the malting period was studied by a combination of gel electrophoresis, liquid chromatography and mass spectrometry. Water soluble proteins were extracted from barley grains at different times of malting and separated by gel electrophoresis. Protein Z was clearly identified in the band at a position of about 43 kDa and further studied by MS with matrix-assisted laser desorption/ionization technique in detail. From the analysis, we found that protein Z glycation is detectable from the second day of malting. The glycated peptide was observed as a weak signal of m/z 2,619 in the MS spectrum. To confirm the presence of glycation, the MS/MS experiments of both unmodified (m/z 2,457) and modified peptides (m/z 2,619) were carried out. We successfully established a procedure based on the monitoring of glycated peptides in positive reflectron mode to monitor the progress of malting using protein Z as a model protein that might be a potential marker reflecting this technological process. We also demonstrated the high suitability of MS/MS analyses to provide more structural information on peptide modifications.     

制麦工艺中添加剂的筛选研究

通过培养皿小试对影响大麦发芽的添加剂进行单因素筛选,来确定添加剂的最佳浓度.试验结果表明:添加剂赤霉素GA对大麦的发芽率有显著性影响,最佳浓度为0.2 mg/kg;甲醛HCHO可以显著抑制大麦根叶芽的生长,最佳浓度为0.05%;溴酸钾KBrO3可抑制大麦根叶芽的生长,最佳浓度为100 mg/kg;氢氧化钠NaOH可以抑制大麦的根叶芽影响显著,最佳浓度为为O.2 g/L.     

赤霉素对法麦制麦特性的影响

研究了一定浓度的硫酸锌配合不同浓度的赤霉素处理对麦芽生长代谢以及麦芽品质的影响.结果表明,当赤霉素处理浓度为0.10mg/L时,麦芽中有机锌含量最高可达150.9μg/g:赤霉素提高了绿麦芽的呼吸强度和各种酶活性;提高了成品麦芽的α-淀粉酶和β-淀粉酶活性;影响了麦芽中糖类和蛋白质的含量;赤霉素不同程度地提高了麦芽的酿造品质.