发酵菌种对打瓜酒风味的影响

研究采用GC-MS、电子鼻技术和感官评价结合的方法评价发酵菌种对打瓜酒风味的影响。研究分别使用红葡萄酒果酒专用酵母、果酒专用酿酒酵母、葡萄酒活性干酵母和酒曲酵母为发酵菌种,对打瓜汁进行发酵、陈酿,比较4种打瓜酒中挥发性物质组成和风味特征。结果显示4种打瓜酒中分别检测出21、23、28和18种挥发性成分,红葡萄酒果酒专用酵母发酵打瓜酒主要挥发性成分为乙酸异戊酯（17.2%）,果酒专用酿酒酵母和葡萄酒活性干酵母发酵打瓜酒主要挥发性成分为癸酸乙酯（22.7%和18.8%）,酒曲酵母发酵打瓜酒主要挥发性成分为辛酸乙酯（18.3%）;电子鼻检测发现酒曲酵母发酵打瓜酒与其它3种打瓜酒风味存在显著性差异,其油脂香和草香气较明显。结合GC-MS、电子鼻和感官评价结果,发现采用葡萄酒活性干酵母生产的打瓜酒总体风味最佳,香气浓郁、酒香和果香协调。      

Influence of nitrogen on the biological aging of sherry wine

Nitrogen compounds are essential to the growth and metabolism of yeasts. The uptake and metabolism of nitrogen compounds by Saccharomyces cerevisiae depend not only on the strain and its physiological condition, but also on the chemical and physical properties of its environment. The effect of the addition of different amino acids (L ‐proline, L ‐threonine, L ‐arginine, L ‐glutamic acid, L ‐leucine and L ‐valine) to nitrogen‐depleted natural or nitrogen‐free synthetic wine on the cell growth, flor velum formation and sherry wine compound production was investigated under controlled biological aging by S. cerevisiae var. capensis strain G1 a typical flor yeast. The formation of flor velum was dependent on particular amino acid, oxygen availability and the composition of wine. Consumption of glycerol was related with the cell growth; in contrast, acetaldehyde tended to be released. Amino acid supplementation resulted in the release to wine of amino acids, esters and higher alcohols. The amino acid which was released in nearly all cases was L ‐leucine. Addition of L ‐glutamic acid resulted in the release mainly of ethyl acetate, in the case of L ‐leucine isoamyl alcohols were released, and for L ‐valine isobutanol. In the three cases, 1,1‐diethoxyethane was released in large quantities. The findings might indicate that the regulation of metabolism succeeds in the most efficient balancing of the redox potential. Copyright © 2006 Society of Chemical Industry     

Impact of yeast starter formulations on the production of volatile compounds during wine fermentation

The most diffused starter formulation in winemaking is actually represented by active dry yeast (ADY). Spray‐drying has been reported as an appropriate preservation method for yeast and other micro‐organisms. Despite the numerous advantages of this method, the high air temperatures used can negatively affect cell viability and the fermentative performance of dried cells. In the present study, 11 wine S. cerevisiae strains (both indigenous and commercial) were submitted to spray‐drying; different process conditions were tested in order to select the conditions allowing the highest strain survival. The strains exhibited high variability for tolerance to spray‐drying treatment. Selected strains were tested in fermentation at laboratory scale in different formulations (free fresh cells, free dried cells, immobilized fresh cells and immobilized dried cells), in order to assess the influence of starter formulation on fermentative fitness of strains and aromatic quality of wine. The analysis of volatile fraction in the experimental wines produced by selected strains in different formulations allowed identification of > 50 aromatic compounds (alcohols, esters, ketones, aldehydes and terpenes). The results obtained showed that the starter formulation significantly influenced the content of volatile compounds. In particular, the wines obtained by strains in dried forms (as both free and immobilized cells) contained higher numbers of volatile compounds than wines obtained from fresh cells. Copyright © 2014 John Wiley & Sons, Ltd.     

天然酵母菌株在葡萄酒酿造中的应用研究

以河北产赤霞珠葡萄为原料,用本土天然酿酒酵母菌株Y14和商业酵母菌株F15酿造干红葡萄酒,并采用固相微萃取结合气质色谱的方法对葡萄酒中的挥发性香气物质进行检测。结果表明,本土酵母菌株在发酵能力方面与商业酵母无明显差别,但在不同酵母发酵葡萄酒中的香气成分种类和含量方面具有较大差别,本土酵母菌株Y14在香气成分生成能力方面具有优势。因此,此菌株具有生产本地特色葡萄酒的潜质。     

枣酒酿造用酵母的筛选及发酵性能研究

以枣庄长红枣发酵液和枣园土壤为酵母菌株的分离源,经过富集培养和多次划线分离纯化,来获得优良的枣酒酿造酵母菌株。经过酵母菌株的产气性能和产酒精性能比较,以及耐酒精、耐酸、耐糖、耐SO2等耐性试验,得到了发酵性能较强的酵母菌株Z03、Z13、Z34。经过染色,镜检观察其细胞形态和芽殖方式,确定为酵母菌,经WL培养基培养后观察,初步鉴定其属于酵母属的酿酒酵母（Saccharomyces cerevisiae）。将这三株酵母与活性干酵母按照枣酒发酵工艺程序进行发酵,发酵出来的枣酒经感官评定和理化检测,最终筛选出适合枣酒发酵酵母菌株Z13和Z34,其酒精度为9.5%vol和10.8%vol。     

氮源对葡萄酒酵母发酵性能影响的研究进展

酵母对于葡萄酒发酵至关重要,其在酒精发酵中有特定的营养需求。氮源作为葡萄的内源性营养物质,对酵母的生长代谢、发酵速率及香气等次级代谢物的产生有重要影响。在葡萄酒酿造过程中,酿酒酵母占据主导地位,其对氮源的利用和代谢已有广泛研究。近年来,由于非酿酒酵母的优良发酵特性被逐渐挖掘,相关研究激增;氮源对其生长与发酵性能的影响也成为研究热点。该文综述了近年来氮源对于酿酒酵母和非酿酒酵母生长、发酵及产香能力影响的研究进展,并讨论了未来潜在研究领域与方向,以期为我国葡萄酒酵母发酵特性及混合发酵中营养管理策略的深入研究分析提供借鉴与参考。     

两种酵母发酵海红果酒的相互作用研究

探究了酿酒酵母（Saccharomyces cerevisiae）FY2的发酵上清液和细胞浆液对柠檬形克勒克酵母（Klockera apiculata）生长的影响,以单一菌种发酵作为对照,通过测定两种酵母不同比例混合发酵中乙醇生成量、CO2排放量及其酵母菌数量变化探索其在海红果酒发酵过程中的相互作用。结果表明,酿酒酵母FY2的发酵上清液对柠檬形克勒克酵母的生长具有抑制作用且对2 g/L的胰蛋白酶处理和70 ℃热处理敏感;混合发酵36 h后柠檬形克勒克酵母的生长受到抑制,发酵至108 h后已检测不到柠檬形克勒克酵母。     

不同发酵剂对红枣果酒发酵品质的影响

选取4种不同的发酵剂（帝伯仕LA DELICIEUSE活性干酵母（LA-D）、安琪酵母、清香型酒曲和薯曲）分别对红枣进行发酵,通过对感官评分、酒精度、色度以及发酵过程中营养成分含量变化和抗氧化活性等指标进行比较,筛选出一种性能较优的发酵剂。结果表明,LA-D酵母发酵酒的色泽透亮,为琥珀色,苦味较小,枣香味浓郁,感官评分达88.5分,酒精度为10.6%vol;在发酵第12天,VC含量为213.37 mg/100 mL、总黄酮含量为3.49 mg/mL、氨基酸态氮含量为933.3 mg/100 mL,均高于其他三种酵母发酵酒,总多酚含量为0.212 mg/mL,仅次于清香型酒曲发酵酒。枣酒的抗氧化性实验结果表明,在发酵末期,LA-D酵母发酵酒的还原力、羟基、超氧阴离子、DPPH自由基清除率分别为2.425、77.38%、88.75%、92.8%。通过以上实验,分析得出LA-D酵母是最适合红枣果酒发酵的酵母。     

不同酿酒酵母对起泡葡萄酒品质的影响

将经过一系列筛选得到的S1、S2、S3三株酿酒酵母以EC1118为对照进行起泡葡萄酒酿造试验,用自制装置对起泡葡萄酒瓶内发酵压力变化进行监控,并对起泡葡萄酒的理化指标、品评结果进行分析.结果表明,在相同加糖量情况下,不同酿酒酵母将糖转化为瓶内气体的效率不同;发酵生成的起泡葡萄酒与基酒相比,其挥发酸,酒精度均有所增加;还原糖、总酸在不同菌株间差异不明显;起泡酒外观、香气、口感的品评结果,依菌株不同存在差异.     

猕猴桃果酒酿造专用酵母菌株的筛选

以猕猴桃果皮和果园土壤为出发材料,经菌株形态初筛以及菌株发酵特性复筛,得到了一株酵母菌株T-13。经形态学、生理生化和分子生物学鉴定,确定该菌株为酿酒酵母（Saccharomyces cerevisiae）。菌株T-13发酵试验结果表明,经菌株T-13发酵猕猴桃汁72 h后,猕猴桃汁降糖9.9 °Bx,CO2质量损失13 g（6.13%）,所产猕猴桃果酒的酒精度为5.8%vol,优于筛选到的其他酵母和市售果酒酵母,说明菌株T-13的发酵能力较强。经感官评价和气相色谱质谱联用（GC-MS）对风味成分分析发现,菌株T-13所产的猕猴桃原酒风味较好,主要表现在丁酸乙酯、苯乙醇、乙基9-癸烯酸酯等风味物质的增加,并且能保留猕猴桃浆果的典型风味特征。     

以甘蔗固定化酵母发酵低醇葡萄酒的研究

试验以甘蔗为载体材料,研究了用甘蔗块固定化酵母在低醇贵人香葡萄酒发酵中的表现,检测了其对发酵时间,酒精度,稳定性及发酵批次等的影响,同时定量分析了固定化前后酵母发酵低醇酒在香气成分上变化.结果发现,以甘蔗为载体固定化酵母应用到低醇酒发酵,可以有效地控制低醇葡萄酒的理想酒精度,增加产品的稳定性.而且甘蔗固定化酵母减少了酒中高级醇的含量,增加了低醇葡萄酒的复杂香气和口感.     

梨酒酵母的筛选及鉴定

以梨的果皮和梨园土壤作为分离源进行梨酒酵母的分离、筛选,期望得到发酵性能好的适合于梨酒发酵的菌株。首先对酵母菌富集培养和分离,再通过TTC平板一级筛选,杜氏发酵管二级筛选,三角瓶发酵三级筛选,得到菌株YDJ05。实验结果表明该菌株在梨汁中发酵能力较强,产酒精能力较好,即发酵7d产酒率达到8.8%,且残糖较低,产香较好,可作独立的发酵菌株使用。经过26S rDNA D1/D2区序列分析,鉴定为酿酒酵母(Saccharomyces cerevisiae),命名为Saccharomyces cerevisiae YDJ05。     

河北产区优选酿酒酵母的中试研究

将分离自河北产区的3株本土优良葡萄酒酿酒酵母菌株NJ5、N19、NJ17用于葡萄酒中试发酵,考查不同酵母菌株的发酵性能、所发酵葡萄酒的理化特征、多酚类物质含量和挥发性香气成分组成.结果表明,3株本土酿酒酵母具有良好的发酵性能,可生产具有典型地域特征的葡萄酒,有望于用于河北地区特色葡萄酒的生产.     

不同酿酒酵母在菠萝果酒中的发酵特性

选取4株不同的酵母(CY3079、DV10、K1、QA23)为研究对象对菠萝皮渣进行发酵,通过对感官评分、色度、酒精度及发酵过程中抗氧化活性等指标进行比较,筛选出一株性能较优的酵母。结果表明:QA23酵母发酵酒的感官评分高达86分,其次是CY3079酵母发酵酒。CY3079、K1和QA23酵母发酵酒L^*和b^*均高于DV10酵母发酵酒。四种酒酒精度均达10% vol以上;发酵过程中黄酮含量变化相对平稳,多酚含量呈先升后降又上升的复杂变化趋势,抗氧化活性变化与多酚的趋势相近。酵母QA23发酵的菠萝果酒在第6 d时黄酮、多酚含量最高,分别为(0.29±0.021) mg/mL和(455.90±9.87) μg/mL,DPPH和ABTS自由基清除能力IC50值分别达到(4.40±0.29) mg/mL和(0.74±0.03) mg/mL,与CY3079、DV10和K1三种酵母发酵酒相比具有较高的抗氧化活性。QA23是最适合菠萝果酒发酵的酵母,为菠萝皮渣的加工利用提供理论依据。     

Influence of fermentation parameters on phytochemical profile and volatile properties of mulberry (Morus nigra) wine

In the present study Box–Behnken Design was employed to analyse the effects of fermentation parameters such as temperature (T _F), pH, inoculum size (I _S) and °Brix (B_X) on total phenolic concentration (TPC), total flavonoid concentration (TFC), total anthocyanin concentration (TAC), ethanol concentration (ETHC), total higher alcohol concentration (THAC) and total ester concentration (TESC) for the development of a phytochemical‐rich wine using mulberry as a substrate. The results demonstrated that fermentation parameters significantly alter the wine characteristics. Hence, a wine with excellent consumer preference (overall acceptability of 8.51) and high concentration of phytochemicals (TPC = 6014.03 ± 27.80 mg L⁻¹, TFC = 4791.35 ± 21.22 mg L⁻¹, TAC = 1480.72 ± 5.33 mg L⁻¹) as well as good aromatic properties (ETCH =82.85 ± 0.87 g L⁻¹, THAC =249.91 ± 0.31 mg L⁻¹ and TESC =52.55 ± 0.17 mg L⁻¹) with high antioxidant activity (DPPH =220.18 mmol·l⁻¹) was obtained at optimized fermentation conditions of T _F = 25°C, pH = 4.00, I _S = 10% (v /v) and B_X = 26. The results from the present study might contribute to strengthening the development of wine containing high concentrations of phytochemical compounds with attractive olfactory attributes. Copyright © 2017 The Institute of Brewing & Distilling     

野生酵母和商品酵母发酵葡萄酒中挥发性成分差异研究

采用顶空固相微萃取（HS-SPME）和气相色谱-质谱联用（GC-MS）技术对5株商品酿酒酵母和7株野生酿酒酵母所酿葡萄酒中的挥发性物质进行分析。结果表明,各葡萄酒中挥发性物质的组成成分相差不大,但在含量上存在差异,野生酿酒酵母所酿造的葡萄酒中主要挥发性物质的总含量要高于商品酿酒酵母。对于葡萄酒中主要由酵母代谢产生的3类挥发性物质—酯类、醇类和酸类,其含量最高的均为用野生酿酒酵母酿造的葡萄酒,其中以W2和W7最为突出。感官分析结果表明,C1、C2和W2的果香、花香较为突出,C4和W2具有明显的草本味,C2和W1的胡椒味较强。      

响应面法优化蜂蜜酒发酵工艺

以狼牙蜂蜜为原料,考察发酵液糖度、温度、pH值等参数对蜂蜜酒品质的影响。试验采用Box-Behnken试验设计和响应面法优化蜂蜜酒发酵工艺,确定最优的发酵条件。结果表明,当初始糖度为25 °Bx、发酵温度为25 ℃、pH值为5.0时所酿制蜂蜜酒的品质最佳,且产品具有蜂蜜独特的风味。     

Effect of additives on the rehydration of Saccharomyces cerevisiae wine strains in active dry form: influence on viability and performance in the early fermentation phase

The effect of five additives on the rehydration process of three commercial Saccharomyces cerevisiae wine strains, in the form of active dry yeast, was tested using the approach of design of experiments. The response to additives was monitored by observing the viability, measured using fluorescence methodology at the end of the rehydration experiments, and fermentative performance, focusing attention on the first phase of fermentation, assessed based on ethanol production and the total number of cells after 48 h from the time of inoculation in synthetic must. The results showed a correlation between viability and the presence of magnesium in the rehydration medium. However, improvement in viability was not associated with better fermentation performance, which was not affected or in some cases significantly reduced. Among the additives examined, only rehydration with inactive dry yeast and ammonium showed a positive effect on the subsequent fermentations, but not for all of the strains tested. In general, considering all of the additives tested, no relationship was found between viability at the end of rehydration and fermentation performance. These findings suggest that the viability of the rehydrated yeast cells may not be a good index of fitness in the subsequent fermentation. Copyright © 2014 The Institute of Brewing & Distilling