啤酒酿造中野生酵母的研究

啤酒酿造中野生酵母的研究吴文芳，张成刚，吕安国，李波（中国科学院沈阳应用生态所）金连武，蒋玲，孙喜春（辽宁铁岭市清河啤酒厂）所谓野生酵母，是指在啤酒酿造过程中出现的除培养酵母之外的所有酵母而言。威尔斯对野生酵母的定义是：任何未经严密选用与控制的酵母，...     

啤酒废酵母酿造酱油的生产工艺

在啤酒的酿造过程中,将会产生大量的酵母副产物,这对于一个年产5万吨生产规模的中型企业来说,其废酵母浆可达750~1000吨.现在我国不少啤酒企业,都是将酵母浆直接投放到环境中去,这就造成了严重的环境污染。而实际上啤酒废酵母含48~55%的蛋白质、23~28%的碳水,化合物、6~8%的核糖核酸、2%的B族维生素、l%的谷胱甘肽,以及丰富的氨基酸     

发泡酒的研究

发泡酒是一种使用辅料高达75%的啤酒,其口感、外观与普通啤酒相似。由于成本较低,使得发泡酒的价格也明显便宜,消费者容易接受。成为众多啤酒生产厂家共同关心的课题。本文研究了不同辅料的影响,外加酶协助糖化对于发泡酒酿造的重要作用,得出了酿造发泡酒的基本工艺。主要研究结果如下:(1)加拿大的麦特卡夫麦芽以其糖化力高、蛋白质含量高成为发泡酒酿造的选用麦芽。(2)外加蛋白酶可促进大麦自身β-淀粉酶的释放,和显著提高浸出液中α-氨基氮的浓度。(3)甜荞中具有生物活性的儿茶素以其优良的理化性质——热稳定性好;溶解度大;抗氧化性等,成为发泡酒酿造辅料选择对象。(4)成功解决了大麦等原材料的粉碎问题,二次粉碎效果较好。(5)对发泡酒的糖化工艺进行了深入的研究,得出了能制备全权麦汁的最佳工艺流程和工艺条件。(6)制得的麦汁经过滤浊度仍很大(即使添加了卡拉胶),静置一段时间后中间有呈雾状沉淀,其余的麦汁澄清透明,色度只有4.0 EBC。雾状浑浊在发酵时会与酵母一同沉淀下来,不会影响啤酒的质量。(7)酒花的添加量为0.03%。(8)由于发泡酒的辅料比为75%,糊化醪的量较糖化醪多。糊化醪在煮沸后需冷却至70℃左右,方能与糖化醪合并。所以要在原有设备基础上——在糊化锅后添加冷却设备,方能适应发泡酒的生产。     

利用酵母营养盐提高酵母活性的研究

通过在麦汁中添加酵母营养盐的实验室试验,讨论了营养盐对酵母特性的影响。     

上面酵母酿造特性的研究

采用4株上面发酵酵母酿造几批同等浓度(12°P)的啤酒,待起发后每天取样测定外观发酵度、真正发酵度、酒精度、双乙酰含量,绘制降糖曲线,然后利用高效液相色谱检测啤酒风味物质4-乙烯基愈创木酚含量。再利用全自动分析仪测定啤酒理化指标,结合感官品评,证明4株上面发酵酵母酿造特性良好。     

酵母增殖用麦汁浓度对其体积和发酵性能的影响

酵母增殖的麦汁浓度(OG)在7.5～17.5°P 范围时,随 OG 的增加会引起细胞体积的变化。这些变化可应用图象分析技术对单一细胞体积进行测定。ale 和 lager 酵母单一细胞体积的均值随 OG 增加,达到17.5°P 时,体积会增加30%。酵母于高浓麦汁(17.5°P)中增殖,及其后来于高浓麦汁中发酵,对其质量有不利的影响。对于标准的 ale 酵母分别于7.5、12.5和17.5°P 的麦汁中增殖,于17.5°P 的麦汁进行发酵,发酵结束的酵母活性分别为93、90和85%,而同样对于标准的 lager 酵母发酵结束时活性分别为98、95和89%。对于 ale 和 lager 酵母同样应用高于12.5°P 的麦汁增殖,再于高浓麦汁中发酵,发酵结束的酵母活性均不超过90%。     

啤酒酿造中可凝固性氮的最佳检测方法

蛋白质变性和絮凝是麦汁煮沸过程中的重要变化，可凝固性氮是其主要检测指标，因此快捷、准确的检测可凝固性氮对于指导生产具有重大意义。本文在可凝固性氮不同方法检测的基础上，从中确定最佳的可凝固性氮检测方法。     

啤酒酿造中氧的作用及其工艺控制

酵母的增殖及发酵与氧息息相关，尤其是增殖期间，氧的供给对酵母后来的发酵性能影响较大。适当的氧含量可以促使酵母合成增殖所必需的甾醇和不饱和脂肪酸。本文主要论述了酵母接种前麦汁溶氧的工艺控制及其原理；酵母活化的实用方法及国外最新的研究成果和趋向。     

玉米的性质及在啤酒酿造中的应用

本文对玉米的性质，加工用途及在啤酒酿造中的应用进行了探讨。     

浅论酵母的环境影响因素

本文旨在分析酵母的环境影响因素，在发酵过程中如何保持酵母性能的稳定。     

糖化工艺对酵母沉降速率的影响

不同糖化工艺对麦汁中的糖分影响较明显,中温65℃时糖含量最低,低温长时间糖化可提高糖含量;糖化温度（68℃）最高时各种氨基酸的含量最高,中温（65℃）时各种氨基酸含量最低,低温（62℃）时各种氨基酸含量居中。糖化工艺对酵母沉降速度的影响：辅料大米用量达最大（45％）时酵母沉降速率最慢;糖化保温时间适中（30min）时酵母沉降速率相对较慢;加麦：澳麦=4：6时酵母沉降速率相对较慢;糖化温度相对较低或较高时酵母沉降速率相对较慢。（孙悟）     

苹果酒酵母增殖培养基的优化

以麦芽汁装液量(mL)、(NH_4)_2SO_4、Na_2HPO_4和 MgSO_4的质量浓度(g/L)为影响因素,以苹果酒酵母细胞浓度(个/L)为考察指标,利用二次回归正交旋转组合设计研究了1株苹果酒酵母增殖所需培养基的数学模型,进而优化了针对该菌株的增殖培养基。研究结果表明,在100mL 三角瓶中,培养开始酵母细胞浓度为 1．923×10~8个/L,麦芽汁装液量20mL,(NH_4)_2SO_4浓度0．196～1．033g/L,Na_2HPO_4浓度2．559～5．566g/L, MgSO_4浓度1．778～3．222g/L 的培养条件下,培养24h 后,酵母细胞浓度可望高于1．125×10~(11)个/L。     

酵母干燥过程中几种包埋剂的比较

以玉米为原料生产酵母,分析比较3种酵母包埋剂的效果,通过测定每克活性干酵母的细胞总数、活细胞率及发酵力,最终确定了以脱水山梨醇单硬脂酸甘油酯作为酵母的保护剂,其最优添加量为1%（酵母干重）,能够使其用于面食的发酵。     

Structural Complexity of the Nitrogen Source and Influence on Yeast Growth and Fermentation

The structural complexity of the nitrogen source strongly affects both biomass and ethanol production by industrial strains of Saccharomyces cerevisiae, during fermentation in media containing glucose or maltose, and supplemented with a nitrogen source varying from a single ammonium salt (ammonium sulfate) to free amino acids (casamino acids) and peptides (peptone). Diauxie was observed at low glucose and maltose concentrations independent of nitrogen supplementation. At high sugar concentrations diauxie was not easily observed, and growth and ethanol production depended on the nature of the nitrogen source. This was different for baking and brewing ale and lager yeast strains. Sugar concentration had a strong effect on the shift from oxido‐fermentative to oxidative metabolism. At low sugar concentrations, biomass production was similar under both peptone and casamino acid supplementation. Under casamino acid supplementation, the time for metabolic shift increased with the glucose concentration, together with a decrease in the biomass production. This drastic effect on glucose fermentation resulted in the extinction of the second growth phase, probably due to the loss of cell viability. Ammonium salts always induced poor yeast performance. In general, supplementation with a nitrogen source in the peptide form (peptone) was more positive for yeast metabolism, inducing higher biomass and ethanol production, and preserving yeast viability, in both glucose and maltose media, for baking and brewing ale and lager yeast strains. Determination of amino acid utilization showed that most free and peptide amino acids present, in peptone and casamino acids, were utilized by the yeast, suggesting that the results described in this work were not due to a nutritional status induced by nitrogen limitation.     

417队让荒废15年的"死井"复活之浅析

湖南省地矿局417队运用定向钻探技术，在斜井中建槽，注水，扩腔，为湖北永祥制盐有限公司救活一口荒废了15年的卤井。这一技术的成功，给盐卤企业采卤老井，旧井的开发利用开辟了一片崭新的天地。     

啤酒酵母抽提物工艺的研究

以啤酒废酵母为原料，经洗涤、过滤、用碳酸氢钠脱苦，离心发离得酵母泥，再配成酵母减自溶制得酵母抽提物，用作食品添加剂，实验表明，酵母自溶的最佳PH值为5．0，最佳温度55℃，最佳时间为32h，添加酶制剂可大大提高自溶介质中的氨基酸含量，复合酶效果更明显。     

Effect of Sugar Catabolite Repression in Correlation with the Structural Complexity of the Nitrogen Source on Yeast Growth and Fermentation

Biomass and ethanol production by industrial Saccharomyces cerevisiae strains were strongly affected by the structural complexity of the nitrogen source during fermentation in media containing galactose, and supplemented with a nitrogen source varying from a single ammonium salt (ammonium sulfate) to free amino acids (casamino acids) and peptides (peptone). Diauxie was observed at low galactose concentrations independent of nitrogen supplementation. At high sugar concentrations altered patterns of galactose utilisation were observed. Biomass accumulation and ethanol production depended on the nature of the nitrogen source and were different for baking and brewing ale and lager strains. Baking yeast showed improved galactose fermentation performance in the medium supplemented with casamino acids. High biomass production was observed with peptone and casamino acids for the ale brewing strain, however high ethanol production was observed only in the presence of casamino acids. Conversely, peptone was the nitrogen supplement that induced higher biomass and ethanol production for the lager brewing strain. Ammonium salts always induced poor yeast performance. The results with galactose differed from those obtained with glucose and maltose which indicated that supplementation with a nitrogen source in the peptide form (peptone) was more positive for yeast metabolism, suggesting that sugar catabolite repression has a central role in yeast performance in a medium containing nitrogen sources with differing levels of structural complexity.     

The Selection of a Dried Yeast Strain for Use in the Apparent Attenuation Limit Malt Analysis (AAL) Procedure

This investigation identifies that Mauribrew Lager 497 strain of dried yeast can be used as a standard strain for the determination of malt apparent attenuation limit (AAL). It provides ferment‐ability results for malt quality evaluation laboratories that are comparable to fresh brewery yeast. It was found that the optimal pitching rate in Congress wort (EBC Analytica, 1998, method 4.5.1), was 1 g per 200 mL, pitched at 25°C and fermented for 24 h at 20°C with agitation to complete attenuation. Preliminary trials also indicated that the Mauribrew Lager 497 dry yeast may be useful to brewers for determining the wort batch attenuation characteristics by the limit gravity test. In this case a pitching temperature of 35°C was found to be optimal with all other conditions as above. For the purpose of malt quality evaluation and brewery quality control the advantages of using a standard dry yeast strain include ease and convenience of use, consistency of quality, and uniformity between laboratories when they are located in separate geographic regions.     

培养基对复合菌液质量的影响

以老窖泥为材料,通过对富集、筛选的复合菌液的研究与应用发现：第6天培养菌液菌体浓度最大。在生产中应用效果最好;同时,不同培养基的C：N比值,对复合菌液的菌体浓度及代谢产物有重要的影响。     

用于醋酸菌营养盐的废酵母自溶液研究

为进一步降低醋酸的生产成本,考察并优化了酵母自溶的影响因素与条件,探索采用廉价的废酵母水解液作为有机氮源替代酵母浸粉的可行性。结果表明,自溶反应的最佳条件为加水量200%,初始pH7,0,自溶温度50℃,食盐添加量3%,时间48h。进一步以酵母自溶液对醋酸菌进行摇瓶培养,结果表明,当以酵母自溶液替代酵母浸粉时,醋酸菌浓度的提高超过54%,醋酸含量的提高超过10%。