1、 1 本科毕业论文外文翻译 译文： 苹果酿酒酵母对不同糖类的发酵动力学研究 来源： ABSTRACT ,J. Inst. Brew. 110(4), 340346, 2004 摘要 ：本文主要研究和讨论的是使用一种 非线性动力学模型来预测 苹果酒酒酵母的发酵特性。实验以 苹果葡萄酒酿酒酵母菌株发酵酵母 CCTCC M201022 的（葡萄糖，果糖和蔗糖）为基材， 通过这个非线性的动力学模型，就可以得到作用于发酵的 不同糖量的 实验数据 。 该模型是用来预测 不同 酵母糖的利用 在发酵 初始阶段中 糖浓度。 经过对实验数据 的观察研究 ， 以及对与 生 长相关 的延长 时间 ，另外再利用 乙醇生
2、产物流方程为基础的模型，对酵母菌的生长以及为形成和维护生物糖消费量 的 观察 是一种成熟的方法 。 经过实验模型拟合， 可以对 模型中的动力学参数进行估计。 对该 模型的 有效性的 实验验证 也是基于苹果冰酒的 发酵 。结果得到 和模型预测 相同的 发酵性能 。这个验证实验中，我们 使用 的是对 不同初始糖浓度设定的糖基。 由此， 本文旨在对 酵母的发酵性能的各种不同的初始浓度糖的影响进行调查， 另外对 一些应用的动力学参数进行讨论。 关键词 ：苹果冰酒；发酵动力学；糖；酵母 前言 苹果酒是用新鲜苹果浓缩液做成的发酵 酒饮料。在欧洲，苹果酒有着很长的历史传统，并且在全球水果冰酒业中占有重要地位
3、。这种酒在中国的销售量已经跃居第二，并且还在不断增长中。今天，用纯培养酵母发酵的苹果酒为先河，在技术进步的发酵酒饮料行业，这些技术影响了苹果冰酒的生产，但是，目前可以搜集的有用信息尚不充分，还不能允许我们完全了解苹果冰酒的全部制作过程。苹果冰酒含有多种糖类，包括果糖、葡萄糖、蔗糖等不同浓度的碳水化合物。与糊状不同，在苹果酒所含的糖分中含量最高的是果糖，占总数的 70%。与酒曲（用于酿酒的酵母）一样，新鲜苹果在酿酒过程中充当着酿酒酵母的 功能，是推动苹果冰酒酿造快速、高效的重要因素。它能产生完整的转化糖，这样，酿成的冰酒2 就没有发酵意味。但是，缓慢和不完整的发酵酒饮料（即，发酵不完全或者不能连
4、续发酵）如何能坚持发酵是葡萄酒产业的一大难题。这个难题可能会导致计划外的损失，比如加工能力不足，生产时间延长和潜在的微生物不稳定，另外还会使得产品口味不好。在这种情况下，果糖是主要因素，造成残糖含量超标。鉴于发酵的重要性，尽管果糖对苹果酒生产有重要影响，但涉及本主题的研究还比较少。此外，其他一些由甘蔗、甜菜或者水解玉米糖浆为发酵糖类，也被应用于苹果酒的生 产。糖含量的变化会影响发酵过程。因此，研究糖的吸收和利用是有其实际需要的，在此过程中使用酵母发酵具有重要意义。 在过去的二十年里，许多写了有关糖的摄取和酵母的利用的论文已经出版。据指出，用酵母生产的酒的量是有限的，这主要取决于糖的吸收率，尤其
5、是果糖的摄取。在一般情况下，同时利用葡萄糖和果糖，葡萄糖比果糖的发酵效率更高。适当的评价葡萄糖含量之间的差异和酒酵母发酵中的果糖消耗应该是有用的解决方法。然而，几乎没有已经被研究出来的有关于葡萄糖或者果糖发酵的系统分析或者量化分析。需要更多的信息来挑选和评估，我们 才能改善酵母菌的发酵性能。 作为一个有用的工具，按照动力学原理开发的葡萄酒发酵模型能够根据最初的果汁特点来预测酵母发酵的性能。开发相应的数学模型来研究发酵动力对研究酵母的发酵和代谢也是十分重要的。随着技术、经济和生理研究的越来越成熟，一个适当的发酵模型将是预测和控制发酵问题的关键，并有助于人们了解发酵过程。进过审查，有几个葡萄酒发酵
6、的物理模型和数学模型都得到了很好的记录方法，因为有很多因素导致问题的发生，如氮和氧就能限制发酵。然而，不同的糖类能产生不同的效果，如果糖、葡萄糖、蔗糖，这些都是苹果和葡萄果 汁中主要的含有的糖类，但是这些在用酵母发酵的苹果冰酒中的性能就不太明确了。 因此，这项工作的目标是要提出一种非结构的苹果酒酵母发酵动力学研究模型，以此来研究不同的糖，其中的一个状态变量为微生物变化数。另外，不同的细胞调控机制并不是必须的。然后，在不同的发酵性能下能对苹果酒酵母对果汁中最初的糖的含量水平能进行预测。以此得到的动力学参数为基础，利用不同的酵母糖比较，对酵母动力特性进行讨论。 材料与方法 3 酵母菌株 有一种酵母
7、菌株叫做酿酒酵母菌株 CCTCCM2001022（中国典型培养物储藏中心），这 是一种用来制作苹果冰酒的酵母，我们选取这个酿酒菌株进行实验。 媒介 为了探讨单糖酵母的发酵效应，合成培养基，用来模拟苹果浓缩液，这样就能组成一种“理想”的用来制作苹果冰酒的苹果汁。 发酵条件 对酵母细胞进行培养，在 25 摄氏度的巴氏门菌内静置 24 小时，然后 2%的酵母细胞要你用来接种。将接种的细胞放到 1 公升的锥形瓶中，再将这些放入刚刚调和成的苹果汁媒介中。 模拟模型 本次实验的模型使用的是 SAS 软件系统，适合于 Windows 8.01 版本的操作系统。这个模型参数在文本中有所描述。 结果与讨论 苹果
8、酒酵母对于 不同糖类的发酵特性显示如下图 1。在细胞生长速率上，这种酵母的发酵性能是有一些差异的。乙醇生产率和糖分解率，分别利用葡萄糖、果糖或者蔗糖作为唯一的糖类。 总结 这种非线性动力学模型能预测一种苹果酒酵母在不同的糖类发酵中的变化，而且已经被实验验证了有效性。该模型的预测能力可以作为酒业公司酿造苹果冰酒的参考。这个非线性动力学模型提出了对酵母菌生长的物流方程。乙醇生产有着一段延后的时间。这是一种能够对酵母菌的生理特性进行估计的数学软件。 4 参考文献 1 D. Wang, Y. Xu*, J. Hu and G. Zhao. Fermentation Kinetics of Differ
9、ent Sugars by Apple Wine Yeast Saccharomyces cerevisiae. Journal of the Institute of Brewing. 2004, 110(4): 340346. 2 Yan Y H, Gao Z P. Industrialization of Chinese jujube. Journal of Northwest SciTech Universit -y of Agriculture and Forestry,2002,30(12):95-98.(in Chinese). 3 Wang J, Zhang B S. A re
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11、s of Greek kiwi wi -ne; sensory evaluation and optimization of its composition. Food Chemistry,2001,75:487-500. 6 Yang H F. Standard Manual of Foodstuff Hygienic Physics and Chemistry Test. Beijing:Standa -rds Press of China, 1997:53-66; 577-617.(in Chinese). 7 Kermasha S, Goetghebeur M, Dumont J. A
12、nalyses of phenolic and furfural compounds in conc -entrated and non-concentrated apple juice. Food Research International, 1995,28:245-252. 8 Huang Y D. The fermentation of methanol and the analysis of the poisonous of methanol in red bayberry wine. Liquor-Making Science and Technology, 1999,92(2):
13、60-61.(in Chinese). 9 Cheng G, Bai Y J, Zhao Y Y. Flavonoids from Ziziphus jujube var. spinosa. Tetrahedron,2000,5 6:8 915-8 920. 外文翻译原文 5 Fermentation Kinetics of Different Sugars by Apple Wine Yeast Saccharomyces cerevisiae ABSTRACT J. Inst. Brew. 110(4), 340346, 2004 A non-linear kinetic model to
14、 predict the consumption of different sugars (glucose, fructose and sucrose) as a substrate, during an apple wine yeast fermentation with Saccharomyces cerevisiae strain CCTCC M201022 is proposed. This model was used to predict sugar utilization by this yeast beginning at various initial sugar conce
15、ntrations. After observation of the experimental data, a model based on the logistic equation of yeast growth, growthassociated production of ethanol with a lag time, and consumption of sugars for biomass formation and maintenance, was developed. After experimental model fitting, kinetic parameters
16、in the model were estimated. The experimental verification of the model was performed using flask-scale fermentations, and the model obtained predicted the fermentation performance effectively, using different sugars as the substrate set at various initial sugar concentrations. Based on estimated ki
17、netic parameters and the characteristics of sugar utilization, the yeast examined appeared to be glucophilic. The effects of different sugars with various initial concentrations on the fermentation performance by this yeast were investigated, and some applications of kinetic parameters are discussed
18、. Key words: Apple wine, fermentation kinetics, sugar, yeast. INTRODUCTION Apple wine is a fermented beverage made from fresh or concentrated apple juice. It has had a long tradition in Europe and has taken an important place in the global fruit wine industry11. It has become the second largest frui
19、t wine industry with an increasing demand in China. Today the use of selected pure cultures of yeast for fermentation of apple wine as starters, and the technological advances in other parts of the fermented beverage industry have influenced the apple wine making process, however the available infor
20、mation is not sufficient yet to permit a full understanding and control of the process5,11. Apple juice contains many sugars, including fructose, glucose, sucrose as well as other carbohydrates, in varying concentrations. Unlike mash, the sugar in the highest amount in apple juice is fructose, up to
21、 70% of the total fermentable sugar of 100150 g/L, plus glucose and sucrose5,11. Like wine yeast, the primary function of apple wine yeast (Saccharomyces 6 cerevisiae is the major industrial strain) is to catalyze the rapid, efficient and complete conversion of sugars to alcohol without the developm
22、ent of fermentation off-flavors. However, slow and incomplete alcoholic fermentations of juice (i.e., sluggish or stuck fermentations) are a chronic problem for the fruit wine industry3. This can lead to unscheduled loss of tank capacity due to extended processing times and the potential for microbi
23、al instability and off-taste of the final product due to residual sugars. In these cases, fructose is the major factor, causing a high residual sugar concentration. In spite of the importance of fructose fermentation for apple wine production, few studies have addressed this subject. Furthermore, ot
24、her fermentable sugars from cane, beet or hydrolyzed corn syrup are commonly used as adjuncts in apple wine production. The changes in sugar content will affect the fermentation process. Hence the need for a practical investigation into the mechanism of sugar uptake and utilization and the kinetic b
25、ehavior of fermentation by yeast used in this process is significant. Over the past 20 years, numerous papers concerning sugar uptake and utilization by yeast have been published1. It is stated that the rate of alcohol production by yeast is limited primarily by the rate of sugar uptake, especially
26、the uptake of fructose16,17. In general, while both glucose and fructose are utilized simultaneously, glucose is utilized faster than fructose by yeast7,21, and S. Cerevisiae appears to be glucophilic, although some strains have a clear preference for fructose18. An appropriate evaluation on the dis
27、crepancy between the amount of glucose and fructose consumed by wine yeast strains during fermentation might be helpful to solve, at least partially, the problems caused by the slower fermentation of fructose2. However, few systematic analyses or quantifications of the preference for glucose or fruc
28、tose of yeast strains for apple wine have been carried out. More information is required to select and evaluate yeasts to improve fermentation performance. As a useful tool, the primary objective of a kinetic model developed for wine fermentation is the prediction of the kinetic behavior of yeast fe
29、rmentation performance based on the initial characteristics of the juice. The development of the corresponding mathematical models of fermentation kinetics is also important in the research of yeast behavior and metabolic regulation19. An appropriate model of fermentation, with the technical, econom
30、ic and physiological implications would be a powerful instrument to predict and control problem fermentations, and be MATERIALS AND METHODS 7 Yeast strain One yeast strain, Saccharomyces cerevisiae strain CCTCC M201022 (China Center for Type Culture Collection) for apple wine fermentation, selected
31、by this laboratory22, was used for the experiments. Medium In order to investigate the effect of a single sugar on yeast fermentation, a synthetic medium was prepared to simulate an apple juice concentrate, according to the composition of an ideal apple juice used for apple wine Fermentation conditi
32、ons Yeast cells were cultured at 25C in a pasteurized medium for 24 h, and then a 2% (w/v) inoculum was used to inoculate one litre of medium in a 2 litre Erlenmeyer flask, equipped with fermentation air locks. Model simulation Model simulations and data fitting were performed using the SAS software
33、 System for Windows version 8.01 (SAS Institute, Cary, NC). Model parameters are described in the text. RESULTS AND DISCUSSION The fermentation profiles of apple wine yeast on the different sugars are shown in Fig. 1. There were some differences in fermentation performance of this yeast, in cell gro
34、wth rate, ethanol production rate, and sugar consumption rate, using glucose, fructose or sucrose as sole sugars, respectively. Based on the experimental data of the different sugars, some kinetic parameters, including yeast maximum specific growth rate (m) and maximum biomass concentration (Xm), th
35、e yield coefficient (Yp/x) and lag time (t), Yx /s and maintenance coefficient (m), were estimated by mathematical software with Eq. (2), Eq. (4) and Eq. (6), respectively. The estimated values of the parameters are given in Table I. The estimated values of m agreed with those generally exhibited by
36、 yeasts under the present conditions6,10. By the method of fermentation kinetics, the effects of the different sugars are described in detail. CONCLUSIONS A non-linear kinetic model for different sugar fermentations by one industrial Saccharomyces cerevisiae apple wine yeast is proposed, based on th
37、e logistic equation of yeast growth, 8 growth-associated production of ethanol with a lag time, and consumption of sugars for biomass formation and maintenance. Some kinetic parameters with physiological significance in the model were estimated by mathematical software. The experimental verification
38、 of the model was performed using flask-scale fermentations. The results obtained indicated that the model could predict fermentation performance using different sugars as the substrate with various initial sugar concentrations. Moreover, some kinetic parameters obtained, such as m, Xm, Yx /s , m, could be used as indicators for selection or evaluation of potential glucophilic or fructophilic yeast strains. The predictive capability of this model has potential as a useful tool for determining how to address apple wine fermentation issues.
