微生物共发酵纤维质原料产单细胞油脂特性研究

对黑曲霉SL2-111和产脂酵母AS2．1560利用纤维质原料混合发酵生产单细胞油脂的主要影响因素进行初步研究。通过均匀设计试验,探讨了双菌株混合发酵的适宜条件。结果表明,两菌株混合发酵生产油脂的适宜条件为：培养基中C：N比为70：1,含水量为12．9mL;黑曲霉接种22．5h后接入产脂酵母,接种比例为3：7（黑曲霉：产脂酵母）,发酵周期为114．5h。产油率可达3．98g／100g。     

优良产酯酵母菌的筛选及发酵性能研究

从大曲中分离获得6株酵母菌,通过对菌株形态结构观察和生理特性分类鉴定,初步确定2株高产乙酸乙酯酵母,并对分离菌株发酵动力学及其产酯性能进行研究,其中在最适条件下菌株BQC-1Y产酯量高达663.8mg/100mL,完全适合用于白酒产香的优良酵母菌株。     

西南菌种站部分酿酒增香细菌产酸性能初探

本文主要介绍西南菌种站保藏的部分酿酒增香细菌在不同发酵培养条件下产有机酸能力。试验通过对13株菌株进行比较，结果表明，多数丙酸杆菌在合成液培养基中发酵产酸能力较强，丁酸杆菌在母糟浸液培养基中发酵产酸能力较强，菌株SICC1．314、SICC1．259等不仅产酸较高，而且产酸速度也较快。     

产香酵母的筛选及其苹果酒发酵特性

从分离自赤霞珠葡萄酿酒不同时期发酵液中的酵母菌中筛选产香菌株,并对其苹果酒发酵特性进行研究。结果表明,经感官评定初筛,获得7株产香较优的酵母菌,并对其进行耐酒精、耐SO2和耐盐性能分析,其中菌株B2-13具有较好的发酵性能,经分子生物学鉴定菌株B2-13为葡萄酒有孢汉逊酵母（Hanseniaspora uvarum）。菌株B2-13发酵苹果酒酒精度为4.2%vol～5.5%vol,糖度为2.6～44 g/L,共鉴定出32种香气成分,主要有酯类（6种）、醛酮类（4种）、醇类（6种）、酸类（8种）等,其中异戊醇、苯乙醇含量最高,分别为0.36 mg/mL和0.16 mg/mL,另外还有赤霞珠干红葡萄酒的特有香气物质3-羟基-2-丁酮（0.16 mg/mL）。菌株B2-13是一株具有较好的苹果酒发酵和产香性能的酵母菌株,有良好的工业化生产应用前景。     

蜂蜜酒生香酵母产酯性能比较和产酯条件研究

对6株生香酵母在蜂蜜酒发酵中的产酯性能进行比较,探讨生香酵母的产酯条件,为蜂蜜酒的发酵提供参考。结果表明。异常汉逊酵母异常变种（Hansenula anomala var. anomala）1437产酯最高,为0．8431g／L;该菌株产酯开始时的乙醇浓度以5％-6％比较合适,最适pH为5,最适温度为25-28℃,装液量以40％-50％较好,连续振荡不利于产酯;接种生香酵母2d后再接入1％酿酒酵母（Saccharomyces cerevisiae）1306能促进异常汉逊酵母异常变种1437产酯。     

一株产香酵母菌的筛选及应用于发酵馒头的研究

采用嗅闻法和总酯滴定法从老酵子中分离筛选产香菌株,通过形态学观察及分子生物学技术对其进行鉴定,并对其生长条件进行研究,最后,采用气相色谱-质谱（GC-MS）法测定添加产香酵母发酵馒头和未添加产香酵母发酵馒头中挥发性成分。结果表明,从老酵子中分离出一株产香菌株ZY-01,其发酵液总酯含量为355.2 mg/L,经鉴定菌株ZY-01为异常威克汉姆酵母（Wickerhamomyces anomalus）。菌株ZY-01的最优生长条件为：生长时间为28 h,温度28 ℃,pH值4.0。添加产香酵母发酵馒头和未添加产香酵母发酵馒头主要检测出16种、12种风味物质,添加产香酵母的馒头与未添加产香发酵的馒头相比,醇类、酯类物质含量分别增加11.27%、8.85%。     

啤酒酵母突变株发酵性能比较及随机扩增多态DNA分析

对9株啤酒酵母菌种及经过诱变获得的突变株进行了发酵试验，比较了不同菌株的发酵能力、产高级醇能力、双乙酰还原能力以及菌株稳定性。同时利用随机引物对不同啤酒酵母株的基因组DNA进行了随机扩增多态DNA（RAPD）分析，比较不同突变株之间基因组的分子差异。结果表明：不同酵母发酵14d后外观发酵度在72．3％-76．8％，其中酵母YZB具有较高的发酵能力，最终发酵产物的高级醇含量最低，双乙酰峰值最低为0．36mg／L，而酵母Y1110最终发酵产物的高级醇含量最低为67．4mg／L，但双乙酰峰值达0．41mg／L，后酵结束后这2株酵母的双乙酰均可降至0．1mg／L以下。菌株稳定性实验结果表明，在传代7次以后和第1代的主要性能没有明显变化。利用随机引物OPG-5对不同酵母的基因组进行RAPD分析，酵母Y1110、YZB和YZD可以通过特异的扩增谱带区别于其它菌株，该结果为啤酒酵母特异的分子标记奠定了基础。     

酵母菌产酒精能力的葡萄糖消耗检测法

研究了1种检测酵母菌产酒精能力的新方法。利用酒精发酵液体培养基在厌氧条件下对产酒精酵母菌株YE-1、YE-2、YE-3进行酒精发酵培养,同时利用菌体发酵培养基在有氧条件下进行菌体培养实验作为对照。通过分光光度法检测培养基中葡萄糖的消耗量,根据所消耗的葡萄糖中用于酒精发酵的量,推算出3株酵母菌菌株在酒精发酵培养基中酒精含量分别为4.03 mg/mL、3.50 mg/mL和3.77 mg/mL,进而比较出各菌株产酒精能力的大小。     

海洋红酵母产类胡萝卜素的研究

从海洋中筛选出1株产类胡萝卜素能力较强的红酵母RY-8。研究了不同碳源、氮源、装液量和pH值对菌株RY-8生物量和产类胡萝卜素的影响，并通过正交试验优化其产类胡萝卜素的发酵条件。结果表明，红酵母菌株RY-8产类胡萝卜素的最佳发酵条件为：葡萄糖25g/L，酵母膏10g／L，装液量60mL/250mL，pH值6．0。在此优化条件下，红酵母RY-8的生物量和类胡萝卜素产量分别为48．8g／L和4．76mg／L，依次比初始产量提高了20．8％和38．4％。     

产酯酵母的筛选及其发酵特性研究

从大曲中筛选到8株产酯酵母,选酶活最高菌株进行26S rDNA鉴定,确定其为异常毕赤酵母.试验结果表明,该酵母麸曲的酯化力可达到19.36 mg/100 mL.该菌株麸曲最佳培养时间为6d;液体培养最高耐受温度为43℃;最低耐受pH值为3.5;最高耐受酒精度为18 ％vol;最适生长温度为27℃;利用葡萄糖产酒精能力较低.     

陈酿时间对发酵型香菇酒香气成分及酒体风味的影响

采用顶空固相微萃取与气相色谱-质谱联用技术对发酵型香菇酒陈酿早期香气成分变化进行动态检测,通过峰面积归一法计算各香气成分相对含量,并结合相对香气活度值（relative odor activity value,ROAV）进行分析。结果表明：发酵型香菇酒在陈酿早期形成大量香气成分,检出54 种,其中1-辛烯-3-醇、异戊醇、癸酸乙酯等8 种挥发性香气化合物是发酵型香菇酒具有独特风味的主要原因。陈酿早期香菇酒香气成分变化较大,醇类与酸类香气物质的相对含量总体下降,酯类香气物质相对含量明显上升,其他类香气物质变化不大。陈酿60 d及陈酿180 d的成品香菇酒的香气成分相对含量及ROAV,差异不显著（P＞0.05）。证明在陈酿早期即形成了发酵型香菇酒的主体香,提示生产中可适当缩短发酵型香菇酒的陈酿时间,缩短生产周期,提高生产效率。     

提高郫县豆瓣甜瓣子品质的工艺条件优化

以郫县豆瓣生产过程中分离到的米曲霉（Aspergillus oryzae）、黑曲霉（Aspergillus niger）、根霉（Rhizopus）为出发菌种,以感官评价和氨基酸态氮及综合酶活力为评价指标,筛选出功能米曲霉（Aspergillus oryzae）SICC3.1083和SICC3.930进行提高甜瓣子品质研究。通过单因素试验,筛选出混合种曲比例、发酵温度、盐分3个显著影响因素,采用响应面法优化混合种曲发酵工艺条件。结果表明,最佳发酵工艺为米曲霉SICC3.1083和SICC3.930质量比1.0∶1.0、发酵温度40 ℃、发酵时间25 d、盐分12%。在此优化工艺条件下,甜瓣子感官评分为88分,氨基酸态氮含量为0.78 g/100 g,比优化前分别提高了17%和20%,感官评分和理化指标均优于传统发酵工艺。     

商业酵母对马瑟兰干红葡萄酒香气成分的影响

以酿酒葡萄品种马瑟兰为原料,分别用4种商业酵母单一或混合酿制马瑟兰干红葡萄酒,采用顶空固相微萃取（HS-SPME）和气质联用（GC-MS）技术对其香气成分进行分析,探究山东蓬莱产区马瑟兰干红葡萄酒的香气组成,同时为生产实践选择合适的酵母。不同酵母酿制的马瑟兰干红葡萄酒共检测到79种挥发性物质,通过对其香气成分进行分类比较分析表明,酵母71B所酿制的酒具有较高的C6醇、乙酸酯;酵母BDX所酿的酒具有较低的己醇、辛酸、己酸,较高的脂肪酸乙酯、苯乙醇、3-乙氧基丙醇;酵母K1和D254酿制的酒中乙酸酯和脂肪酸乙酯的含量都非常接近。混合酵母酿制的酒中高级醇、乙酸酯和脂肪酸含量普遍比单一酵母酿制的酒高。     

Changes in the composition of neutral volatile components during the production of apple brandy

The changes in aroma composition during apple-brandy production have been investigated by gas chromatography and coupled gas chromatography-mass spectrometry. Quantitative determinations of 97 aroma components have shown that the aroma of unaged apple brandy is characterised by components produced as a result of the yeast fermentation and technological steps such as mashing and heating rather than by the genuine apple-aroma components. Genuine apple-aroma constituents, predominantly esters, are degraded during the mashing process and can be detected only in traces after the distillation. Distillation enhanced the concentration of ethyl esters and many of the higher alcohols, producing acetals and furane derivatives as well as damascenone, 2-methylhept-2-hepten-6-one and β-cyclocitral.     

A Technological Solution to Modulate the Aroma Profile during Beer Fermentation

During the production of fermented alcoholic beverages, such as wine or beer, the loss of aroma active compounds (AACs) has a significant impact on the overall product aroma. This paper presents the results of an experimental technique in which a condenser was placed on the top of the fermenter in order to reduce such losses. AAC concentrations in beers produced in this way were compared with a control produced without a condenser. There were two main findings: (i) some AACs could be recovered during fermentation and (ii) the technique stimulated the de novo synthesis of esters from carboxylic acids and alcohols. In particular, the production of ethyl esters from the reaction between ethanol and organic acids and the production of acetates from the reaction between acetic acid and alcohols were demonstrated. Consequently, the addition of the condenser changed the final aroma of the beverage. The effect was confirmed by a panel test and AAC quantitation using HS-SPME-GC-MS. The technique could be used by brewers as a tool to modulate the flavor and aroma of beer.     

广东单丛茶树品种红茶香气成分的GC-MS分析

单丛茶树品种是制作单从乌龙茶的主要品种,研究发现其也可用于制作红茶。为明确所制红茶香气物质及主要呈香特征,采用顶空固相微萃取结合气相色谱-质谱联用技术鉴定香气物质种类及其对总体香气的贡献。结果表明,本研究从广东单丛品种红茶中鉴定出46 种香气化合物,主要包括醇类、醛类、酯类、酮类、烯类和烷烃类等,其中醇类是最主要的物质,其次是酯类和醛类。香气化合物中芳樟醇、橙花醇、水杨酸甲酯、氧化芳樟醇和壬醛是5 种最主要的呈香物质,含量占香气总量的60%以上。花蜜香是广东单丛茶树红茶典型的香气特征。     

单一及混合益生菌发酵猕猴桃果汁的香气成分分析

为开发营养健康且果香浓郁的猕猴桃益生菌发酵果汁,以徐香猕猴桃果汁为原料,采用植物乳杆菌115、副干酪乳杆菌及植物乳杆菌115-副干酪乳杆菌混合（1∶1）发酵的3?种益生菌发酵果汁,以原果汁为对照,利用顶空固相微萃取和气相色谱-质谱联用技术对原果汁及发酵果汁的香气成分进行比较分析。结果表明：从4?组果汁样品中共鉴定出74?种香气成分,其中醇类17?种、酮类8?种、酯类19?种、醛类12?种、烷烯烃类8?种、酸类4?种、其他类6?种。混合菌种发酵和单一菌种发酵猕猴桃果汁的香气成分种类、含量及香气值差异显著（P＜0.05）,混合菌种发酵猕猴桃果汁中的醇类、酯类和其他类香气物质的种类和含量显著（P＜0.05）高于单一菌种发酵,赋予了猕猴桃果汁更浓郁的花香和果香。混和菌种益生菌发酵的猕猴桃汁香气物质种类多,含量高,果香浓郁且典型,适于猕猴桃益生菌发酵果汁的生产。     

Evaluation of a volatile aroma preference of commercial red wines in Korea: Sensory and gas chromatography characterization

The aim of this study was to elucidate the Korean consumers’ aroma preference on wines. For this, a sensory test on 6 commercial red wines (5 imported and 1 domestic) was conducted by 250 panels and the volatile compounds of those wines were analyzed by gas chromatography-mass spectrometry. Sample 1 obtained the highest mean aroma acceptability score and analysis of volatile compounds revealed that it retained many kinds of esters and alcohols compared to other wines (including 2 acetate esters, 6 ethyl esters, 3 other esters, and 5 alcohols, mostly giving fruity aroma). Sample 1 was made by blending 2 varieties of grapes and this brewing technology might give a preferred aroma balance. The domestic wine, sample 2, made of ‘Campbell Early’ grape earned relatively higher acceptability score (2^nd ranked), being considered its strong grape aroma. In the lower score group, higher concentrations of isoamyl alcohol, 1-isothiocyanto-propane, and volatile phenol were detected and their strong grassy or fatty odor might affect the lower sensory result. Strategies for production of consumer-preferred wines were suggested.     

采后苯并噻重氮处理对‘玉金香’甜瓜氨基酸代谢酯类香气物质及其代谢机理的影响

以‘玉金香’甜瓜为材料,采后常温贮藏期间分析其氨基酸含量、谷丙转氨酶（glutamate pyruvic transaminase,GPT）、谷草转氨酶（glutamic oxaloacetic transaminase,GOT）、丙酮酸脱羧酶（pyruvate decarboxylase,PDC）、丙酮酸脱氢酶（pyruvate dehydrogenase,PDH）活力及其代谢产物酯类香气物质含量的 变化,探讨采后苯并噻重氮（benzothiadiazole,BTH）诱抗处理对酯类香气物质氨基酸代谢途径影响的机理。结 果表明：BTH诱抗处理可延迟样品酯类香气物质释放高峰出现,抑制其释放,总含量比CK组（未经任何处理） 低19.10%。15 种游离氨基酸被分离确定,CK组氨基酸总含量峰值（14 597 μg/g）出现在第6天,BTH组峰值出现 在第8天,低于CK组9.47%（P＜0.05）。BTH处理抑制了贮藏期间GOT、PDC和PDH活力,与CK组相比,BTH处 理组果皮GOT、PDC和PDH活力峰值分别降低31.80%、16.86%和24.30%,果肉峰值分别降低19.10%、14.70%和 25.56%,果皮GOT活力被显著抑制（P＜0.05）;不同处理组间GPT活力差异不显著（P＞0.05）。氨基酸总含量、 GOT活力与酯类香气物质含量呈极显著正相关（P＜0.01）。水处理对氨基酸含量、代谢酶活力及其产物酯类香气 物质释放均有影响,但无明显作用规律。由此可见,BTH处理会减少氨基酸含量,抑制相关代谢酶活力,进而改变 其产物酯类香气物质的释放。     

Gene expression in wheat beer yeast strains and the synthesis of acetate esters

The synthesis of aroma compounds represents one of the most important parameters in beer production. Although it has been a historical topic of research, exactly how aroma components are formed has yet to be fully explained. Moreover, all of the research that has been published on yeast strains is focused on lagers and ales. Wheat beer yeast strains have not been the focus of aroma and flavour research. In this study, five different wheat beer yeasts were analysed to determine their capacity for producing acetate esters. In this study, the most commonly used wheat beer yeast strains for the production of German‐style wheat beer were analysed. This involved measuring the level of expression of the alcohol acetyl transferase genes ATF1, ATF2 and IAH1 over a period of 4 days (during primary fermentation) and plotting the data to observe the development of expression of the genes over time. Results confirmed their capacity to form acetate esters and showed a distinct correlation with increasing expression of the gene ATF1. However, the findings also indicated that gene expression in different yeast strains can vary considerably during fermentation. Copyright © 2016 The Institute of Brewing & Distilling