The Influence of Inoculum Level on Fermentation and Flavour Compounds of White Wines Made from cv. Emir

In this study, the influence of the addition of a commercial wine yeast (Saccharomyces cerevisiae) at inocula of 1 × 10⁴ to 1 × 10⁷ cells/ml in Emir must was investigated with a focus on yeast growth, fermentation rate, ethyl alcohol and flavour compound formation. Spontaneous fermentation without inoculation was also performed. Higher peak counts were observed with higher amounts of S. cerevisiae yeast. Addition of various amounts of yeast led to the earlier disappearance of non‐Saccharomyces yeasts. The fermentation rate was improved with higher amounts of yeast, but ethanol production was not affected. Concentrations of higher alcohols increased with increasing inoculum levels, especially inoculum sizes of 1 × 10⁶ cells/ml and 1 × 10⁷ cells/ml. The amount of ethyl acetate was reduced with increased inoculum levels.     

The effects of grape must fermentation conditions on volatile alcohols and esters formed by Saccharomyces cerevisiae

Changes in aroma compounds synthesised from grape must during fermentation carried out by Saccharomyces cerevisiae, in semi-aerobic, anaerobic, short aeration conditions and after adding ergosterol and oleic acid to the must were studied. The biosynthesis of these aroma compounds was strongly dependent on the fermentation conditions and on the growth of the yeast. Ethanol, isoamyl alcohols, isobutyl alcohol, phenethyl alcohol and isoamyl, butyl and hexyl acetates were produced in greater concentrations in semiaerobic conditions, mainly during cellular growth. 1-Butanol and 1-pentanol were produced in greater levels in anaerobic conditions, when cellular growth was lower. Ergosterol and oleic acid added to the musts generally increased the levels of the aroma compounds in wine compared to those obtained in anaerobic conditions. © 1997 SCI.     

内蒙古乌海地区沙漠葡萄发酵醪液中酿酒酵母菌的筛选与鉴定

以内蒙古乌海地区沙漠葡萄自然发酵醪液为筛选来源,共分离纯化出22株酵母菌,通过复筛得到1株优良酵母菌KT3,经26S r DNA D1/D2区测序,鉴定为酵母菌属(Saccharomyces)的酿酒酵母菌(Saccharomyces cerevisiae);该酵母菌具有良好的耐受能力,耐酒精度为16%,耐SO2浓度为450 mg/L,耐高糖浓度为50%,耐pH值为2.5;并且具备高产酒精和低产硫化氢的能力,发酵产品风味协调,典型性强,可以用于葡萄酒的生产。     

The Effect of Pitching Rate on Fermentation and Flavour Compounds in High Gravity Brewing

The effect of pitching rate on fermentation and production of flavour compounds was studied in high gravity wort using a lager yeast. Fermentation performance was followed by monitoring the total sugar content and yeast growth. Volatile compounds were evaluated by analysing higher alcohols, esters and carbonyl compounds at the end of fermentation. Faster fermentation rates and higher yeast counts were observed with the higher pitching levels. Lower amounts of 2‐ and 3‐methyl‐1‐butanols and higher levels of 2‐methyl‐1‐propanol were found at the increased pitching rates. The concentration of isoamyl acetate was reduced with an increased pitching rate. Higher amounts of diacetyl and 2,3‐pentanedione were obtained at the lower pitching levels.     

酿酒酵母发酵生产谷胱甘肽的研究

以诱变获得的酿酒酵母突变株YF(ZnCl2r,Ethr)为试验菌株,通过摇瓶发酵、发酵罐补料分批发酵,对突变株发酵生产谷胱甘肽进行研究.确定发酵罐分批发酵的最佳培养条件为:温度30℃,pH 6.0,接种量为20%,搅拌转速为150 r/min,通气量为250 L/h.在补料分批操作方式下,分别考察了摇瓶培养、发酵罐培养...     

Exclusion of Saccharomyces kudriavzevii from a wine model system mediated by Saccharomyces cerevisiae

This study investigated the competition and potential hybrid generation between the species Saccharomyces cerevisiae and S. kudriavzevii in a wine-model environment. Our main goal was to understand why S. kudriavzevii has not been found in wine fermentations whilst their hybrids are present. Auxotrophic mutants (Ura(-) and Lys(-)) were used to favour the selection of hybrids and to specifically differentiate the two species in mixed fermentations carried out at different temperatures (17 °C, 24 °C and 31 °C). Both yeasts showed a reduction in their maximum specific growth rates in mixed fermentations, indicating a clear antagonistic effect between the two microorganisms. Temperature played an important role in this competition. In this way, S. kudriavzevii was less affected at 17 °C, but S. cerevisiae was clearly the best competitor at 31 °C, preventing the growth of S. kudriavzevii. Population levels of S. kudriavzevii always significantly decreased in the presence of S. cerevisiae. Ethanol was measured throughout the fermentations and in all cases S. kudriavzevii growth was arrested when ethanol levels were < 5 g/l, indicating that this compound did not influence the competitive exclusion of S. kudriavzevii. Killer factors were also discarded due to the K(-) R(-) phenotype of both strains. Finally, no prototrophic interspecific hybrids were isolated in small-scale fermentations at any temperature assayed. Our results show that the lack of competitiveness exhibited by S. kudriavzevii, especially at high temperatures, explains the absence of this species in wine fermentations, suggesting that natural S. cerevisiae × S. kudriavzevii hybrids most likely originated in wild environments rather than in industrial fermentations.     

不同酿酒酵母发酵对红葡萄酒中花色苷组成的影响

比较了不同酿酒酵母菌株发酵对红葡萄酒中花色苷组分的影响,为本土酵母的开发应用提供依据。采用本土自筛酿酒酵母菌株Y17和进口商业酵母菌株F15分别酿造干红葡萄酒,并利用高效液相色谱-质谱联用技术(HPLC-MS)对葡萄酒中的花色苷成分进行检测。结果表明,不同酵母发酵葡萄酒中的花色苷成分种类大体相同,但各种花色苷的含量具有较大差别,本土酵母菌株Y17在发酵生产高花色苷含量葡萄酒方面具有优势。     

酿酒酵母发酵生产S-腺苷甲硫氨酸工艺的优化

目的 优化酿酒酵母LS101发酵生产S-腺苷甲硫氨酸(SAM)的工艺.方法 用单因素实验法,通过测定SAM浓度、细胞浓度、胞内SAM含量以及胞外SAM浓度等参数来确定较为适合的工艺.结果 得到适合的培养基组成为:蔗糖10%～12%,L-甲硫氨酸0.4%,尿素1.5%～2%,酵母粉3%,甘氨酸0.1%,生物素4 mg/L.8 L发酵罐间歇分批补料发酵,培养54 h后SAM产量为3.9 g/L,细胞浓度达到42.2 g/L.结论 得到了优化的酿酒酵母LS101生产SAM发酵工艺,提高了SAM发酵水平.     

紫红曲霉与酿酒酵母共发酵对红曲甜米酒风味的影响

研究紫红曲霉和酿酒酵母在红曲甜米酒发酵过程中风味物质形成的作用。利用紫红曲霉和酿酒酵母以不同比例复配进行甜米酒发酵,监测微生物、有机酸和挥发性香气成分的动态变化。结果表明,以发酵12 h为分界点,酵母菌先增加后减少,而红曲菌则同步呈先减少后增加的趋势;添加红曲菌能够显著促进酵母菌增殖。发酵过程中,酒样的糖度不断降低,酒精度不断增加,发酵36 h后有机酸(乳酸、乙酸、柠檬酸、酒石酸)含量迅速增加;随着红曲菌添加量的提高,糖度减少,酒精和有机酸含量均显著增加。发酵过程共检出47种挥发性组分,包括6种醇类、14种酸类、12种酯类、8种醚类、4种醛酮类、2种醌类和1种酚类,其中高级醇类(苯乙醇、香草醇、异丁醇)和酯类(对羟基扁桃酸乙酯)相对含量较高;酸类含量随发酵时间的延长不断减少,而醇类、酯类和醚类含量则不断增加;添加红曲菌使酯类在发酵前期迅速增加,显著提高其含量。综上所述,添加红曲菌共发酵,促进了酿酒酵母增殖,显著增加了有机酸和酯类等挥发性组分的种类和含量,对甜米酒风味物质的丰富具有重要贡献。     

酿酒酵母的发酵优化与动力学研究

研究了酿酒酵母在游离生长条件下细胞生长、乙醇生成和葡萄糖消耗动力学.通过耐高温酿酒活性干酵母在35℃的复合培养基中不通风生长的三水平正交实验,用Gauss-Newton非线性最小二乘法拟合了发酵动力学参数.当发酵液中的葡萄糖浓度远大于饱和生长系数Ks时,酵母细胞的生长代谢规律受葡萄糖的影响很小.乙醇总是减缓酿酒酵母的生长代谢速率,当乙醇浓度达到完全抑制值KP时细胞就停止生长.酵母细胞的自由生长存在极限浓度Kx,而在细胞浓度为Kx/2处获得最大细胞增长率.当发酵液中乙醇浓度低于KP[1-β/(αμmax)]时,在细胞浓度为Kx[1-β/(αμmax)]/2处获得最大乙醇发产率.而高于此乙醇浓度时,乙醇产率随细胞浓度单调增加.在发酵动力学方程的基础上,可根据发酵目标对发酵条件进行优化.     

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.     

转基因酵母S. c MDC 对红葡萄酒发酵及酒质的影响

以蛇龙珠葡萄为原料进行模拟实验,用红葡萄酒酵母(S 101)作对照,探索转基因酵母S.c MDC 对红葡萄酒发酵及酒质的影响。结果表明：用转基因酵母S.c MDC 发酵的葡萄酒总酸含量较低、葡萄酒的干浸出物含量、总酚含量均较高,苹果酸- 乳酸发酵提前完成。挥发酸含量、残糖含量、蛋白质含量与红葡萄酒酵母(S 101)发酵的酒质区别不大。     

阿片肽酿酒酵母工程菌摇瓶发酵工艺

研究了发酵培养基成分、补加方式及外源氨基酸对酿酒酵母发酵和表达的影响．结果表明，发酵前在液体发酵培养基中一次性补加酵母抽提物（YE）有利于目的产物的表达，发酵过程中补加YE不利于目的产物的表达，发酵中后期补加适量的葡萄糖有利于阿片肽的表达．添加外源氨基酸对酿酒酵母工程菌的生长有一定的促进作用，而且可以明显地影响阿片肽的表达．通过正交实验对酿酒酵母生长和表达条件进行优化，确定最优工艺参数为：培养基中酵母抽提物质量浓度为25g／L，C：N比2．8，培养基初始PH5．0，摇床转速220r／min．在最优条件下研究了酿酒酵母表达目的产物的情况，总蛋白质质量浓度为614．50mg／L．SDS-PAGE电泳和双波长凝胶扫描结果表明：目的阿片肽约占总分泌蛋白质的5％，其表达量为30．7mg／L，是优化前的1．49倍。     

模拟葡萄汁中可同化氮和还原糖对酵母发酵特性的影响

为研究葡萄汁中可同化氮和还原糖对酵母发酵特性的影响,设计150、240、330、420、500?mg/L可同化氮质量浓度和170、200、230?g/L还原糖质量浓度,共计15?个处理,测定了模拟葡萄汁酒精发酵过程中酵母生长、还原糖消耗和可同化氮消耗的变化。结果表明,模拟汁中可同化氮质量浓度过低（150?mg/L）则不能充分满足酵母生长的需要,同时限制了酵母的还原糖消耗速率,通过提高初始还原糖质量浓度至200?g/L可促进酒精发酵进行;酵母在初始可同化氮质量浓度高于240?mg/L的模拟汁中可以正常生长,此时初始还原糖、可同化氮质量浓度对酵母生长量均无显著影响,还原糖含量最直接影响酿酒酵母菌株的发酵特性,决定发酵时间长短,表现为在初始还原糖质量浓度较低（170?g/L）的模拟汁中,酵母生长速率随着模拟汁初始可同化氮质量浓度的升高而加快,在初始还原糖质量浓度较高（200～230?g/L）的模拟汁中,酵母生长速率不受初始可同化氮质量浓度的影响;当模拟汁初始可同化氮质量浓度高于330?mg/L时,酵母对可同化氮的消耗开始出现剩余,剩余量随着模拟汁初始可同化氮质量浓度的升高而增加,此时可同化氮质量浓度能够充分满足酵母可同化氮代谢的需要,且酵母对可同化氮消耗量随着初始还原糖质量浓度的增加而略有减少。     

戴尔有孢圆酵母WA19与酿酒酵母F33混合发酵在樱桃酒酿造中的应用

以自主筛选的戴尔有孢圆酵母WA19为研究对象,考察其与酿酒酵母F33混合发酵对樱桃酒品质的影响,同时以酿酒酵母F33单独发酵的樱桃酒、商业化戴尔有孢圆酵母Viniflora Prelude和酿酒酵母F33混合发酵的樱桃酒为对照。研究结果表明,戴尔有孢圆酵母WA19和酿酒酵母F33之间不存在相互抑制,2?种酵母均能快速适应酒体环境,迅速增殖,整个发酵周期为8?d。而酿酒酵母F33与Viniflora Prelude混合发酵则出现了相互抑制的现象。此外,戴尔有孢圆酵母WA19和酿酒酵母F33混合发酵显著提高了多种挥发性组分的含量,如β-苯乙醇、丁酸乙酯、异戊酸乙酯、己酸乙酯、里那醇等,能够增强樱桃酒的果香、花香和发酵香气,使樱桃酒的香气特征更加突出。鉴于戴尔有孢圆酵母WA19的优异性能,有望开发成为樱桃酒专用的产香酵母。     

胁迫条件下酿酒酵母积累海藻糖的发酵研究

采用5L发酵罐对酿酒酵母在高渗、有毒、高温等胁迫条件下海藻糖的积累进行研究，并对发酵过程作了分析。结果表明，胁迫条件比正常条件下更有利于海藻糖的积累。升高温度、添加高渗物质和有毒物质后细胞干重分别提高1．7倍、5．5倍和3．1倍，海藻糖的质量分数由10％分别提高到13．3％、12．7％和14．8％。几种胁迫条件同时存在下与单一胁迫条件比效果并不佳，并非环境越恶劣海藻糖积累越多。大规模生产最有效的方法是在对数生长期提高温度至40℃。     

酿造条件对酿酒酵母发酵香气的影响

采用顶空固相微萃取结合气相色谱-质谱联用技术,比较不同酿酒酵母菌株（CY3079、LA-FR、LA-RA、MST、OFC）在模拟葡萄汁中发酵产香性能,并分析不同酿造条件下各类发酵香气的变化规律。结果表明：LA-FR酵母菌株产酯类、萜烯类物质能力最强,产香性能最好,因而选用LA-FR酵母菌株研究氮源质量浓度、发酵温度、pH值、SO2添加量对各类香气物质的影响。当氮源质量浓度从1.0 g/L增加至2.0 g/L时,LA-FR菌株所产生的醇类、萜烯类物质含量分别降低36.41%和42.56%,酯类、酸类物质含量分别增加72.92%和26.86%;当发酵温度在18～28 ℃范围内变化时,较低温度发酵有利于酯类、萜烯类物质的积累,但不利于醇类、酸类物质的合成;当pH值从3.2升高至3.8时,酯类、萜烯类含量分别增加19.50%和67.43%,醇类、酸类含量分别降低30.24%和34.16%;SO2添加量与醇类、酯类合成量呈正相关,与酸类、萜烯类合成量呈负相关。多元回归分析结果表明,氮源质量浓度对醇类和酯类香气含量影响最大,发酵温度对酸类物质含量影响最大,SO2添加量对萜烯类香气含量影响最大,该研究结果可为深入研究复合因素对发酵香气的影响及葡萄酒香气风味调控提供理论依据。     

酿酒酵母F15和CC17共接种发酵对赤霞珠葡萄酒品质及感官特性的影响

为解决使用单一商业酵母菌株发酵引起的葡萄酒“同质化”问题,本研究以河北昌黎产赤霞珠葡萄为原料,以商业酿酒酵母(Saccharomyces cerevisiae)F15和本土优良酿酒酵母CC17为发酵剂进行单菌株和双菌株共接种(F15∶CC17=1∶1)发酵,同时监测酒精发酵过程中比重、温度、残糖、乙醇、总酸、pH、花青...     

非酿酒酵母与酿酒酵母混合发酵柿子酒特性的研究

基于非酿酒酵母代谢产物可提升酒的香气和风味物质,将两种非酿酒酵母柠檬形克勒克酵母（Klockera apiculata）和东方伊萨酵母（Issatchenkia orientalis）用于柿子酒发酵,研究两种非酿酒酵母对酒精、二氧化硫、单宁的耐受性和产β-葡萄糖苷酶的能力;对它们分别与酿酒酵母（Saccharomyces cerevisiae）混合发酵柿子酒的特性进行研究。结果表明,东方伊萨酵母在各方面耐受性均优于柠檬形克勒克酵母,但产β-葡萄糖苷酶的能力却较弱;两种非酿酒酵母单菌发酵性能都较弱,东方伊萨酵母单菌发酵结束酒精度为4.51%vol,而柠檬形克勒克酵母单菌发酵酒精度只有3.05%vol;两种非酿酒酵母与酿酒酵母混菌发酵7 d后,酒精度均达到10%vol以上。     

分离自烟台白玉霓种植园的酿酒酵母发酵特性研究

以烟台白玉霓葡萄种植园分离筛选的3株酿酒酵母为研究对象,在发酵力、产酒精能力、残糖量、产酸量以及耐酒精度、耐SO2、耐酸能力等方面与商品化活性干酵母进行比较分析.结果表明,本土酵母ZYYT-2具有较好发酵能力,产酒精能力强,产酸量适中,并且能耐受16％vol的酒精度、150mg/L的SO2和2.5％的酸,在葡萄酒酿造条件下发酵良好.