白薯生淀粉酒精发酵的特殊方法

近年来作为代用能源,酒精发酵受到重视。用淀粉为原料,常规的酒精发酵工艺,为了使原料液化和糖化,蒸煮是必须的。它需要消耗整个工艺的30—40％的能源。Vtda和他的同事从事生淀粉生产酒精,已研究用黑曲霉酶制剂,将原料液化、糖化和酵母发酵一步法简单工艺,使之节省用于蒸煮的能源费;他也报导了根霉淀粉酶制剂无蒸煮白薯发酵酒精的工艺。本文报导用肋状拟内霉淀粉酶无蒸煮发酵白薯生产酒精的结果。     

酒精发酵无蒸煮工艺的研究现状

在淀粉质原料生产酒精的过程中,无蒸煮工艺对于减少能源的投入意义重大,受到世界各国科研工作者的重视,并且目前已取得一些可喜的成就。无蒸煮工艺大致分为生料发酵,低温蒸煮,挤压膨化和超细磨。通过研究这几种无蒸煮工艺的理论基础,工艺要点及应用情况,可对工厂的酒精发酵产生导向意义,同时为淀粉发酵生产酒精的节能提供新的研究思路。     

Asp.niger.no.882生淀粉糖化酶性质及动力学的研究

在淀粉原料发酵生产酒精传统工艺中,原料蒸煮耗能约占全部酒精发酵生产能耗的30—40％,因此砍掉蒸煮工序,节约能源、节约投资和降低成本是开发酒精发酵的新课题。解决办法之一是采用无蒸煮发酵法。从理论上讲无论淀粉是熟的还是生的,只要被转化成可发酵性糖,就能被酵母利用。这一转化有赖于生淀粉糖化酶的作用。目前国内外无蒸煮酒精发     

利用马铃薯为原料制醋酒精发酵工艺的优化

为了开发新的食醋品种,研究了以马铃薯为原料制醋工艺中酒精发酵工艺。利用3因素3水平正交试验法,通过对蒸煮温度、蒸煮时间和酒精发酵温度这三个对酒精发酵有重大影响作用的因素进行优化,得到酒精发酵最佳条件为：蒸煮温度130 ℃、蒸煮时间4 min和发酵温度30 ℃。在此最佳发酵工艺条件下,酒精发酵的酒精度可达12.4%vol。     

优良生淀粉酶产生菌Asp.niger.no.882用于生料酒精发酵的研究

酒精发酵,传统工艺都得把原料进行蒸煮和糖化处理,所耗能量约占生产总能的35—40%。为了节能和降低成本,各国都在大力开展无蒸煮酒精发酵的研究,日本已有生玉米酒精生产的专利,国内也有玉米、薯干、大米、高梁等生料酒精发酵的研究。此工艺存在的最大问题是用酶(曲)量过大,一般相当于熟料用酶量的五倍。Y.Han曾报导Asp.niger用于生玉米发酵时用     

浅谈酒精生产应用低温蒸煮浓醪发酵工艺应注意的问题

以淀粉质原料发酵生产酒精的传统工艺:原料→粉粹→高温蒸煮→糖化→发酵→蒸馏→酒精。此工艺采用高温蒸煮来破坏植物细胞间组织和细胞壁,使淀粉溶解并释放出来,以利于淀粉酶的作用。因此,蒸煮这道一工序是必不可少的。 当前,我国酒精厂家大都采用高温蒸煮工艺(温度在130～135℃),这种工艺能源消耗大,约占全部酒精生产能耗的30～40％。因此,要降低酒精生产的能源,必须改进蒸煮工艺。最近几年,我国研制的酒精低温蒸煮浓醪发酵工艺获得成功,蒸煮温度降为85     

关于喷射蒸煮器使用中相关的问题讨论

将原料淀粉加热蒸煮后液化、糖化反应生产葡萄糖供酵母利用,发酵产生酒精和CO2同时放出热量.这是人类数千年来,由作坊式运作到今日工业化自动化生产所必须经过的途径,但如何使淀粉等多糖在短时间内较为彻底的转化为可发酵性的糖,而耗能少,操作简单,一直是人们研究的课题之一.本文将讨论喷射蒸煮器在酒精行业上的应用.     

土豆淀粉在酶作用下的糊化研究

各类植物原料中的淀粉，经过130～150℃的蒸煮，才能使原料中的细胞组织彻底破坏，淀粉充分糊化，有利于糖化酶的糖化和酵母菌的发酵。然而，高温下的蒸煮占酒精生产总能耗的20％左右。为了节约能源，提高经济效益，低温蒸煮或不经蒸煮的酒精发酵便成为该领域的重要研究课题之一。     

低温蒸煮甘薯粉的酒精发酵

<正> 我国酒精生产大部分采用淀粉质原料,尤以甘薯千最为普遍。其传统的生产方法是将甘薯千磨成细粉,调配成浆,经高温高压蒸煮、糖化发酵、蒸馏制得酒精,在这一过程中仅蒸煮工序就要消耗大量的蒸汽,约占整个生产的30％左右,因此,降低蒸煮的能源消耗是酒精     

酒精生产中几个问题的讨论

对蒸煮温度的高低对酒精生产中液化程度、残淀粉的高低、发酵中染菌、发酵中pH值的控制、生料发酵和原料转化率的影响进行讨论,指出我国酒精行业的发展应充分地运用科学技术,使酒精生产水平提高到新的高度。     

氮源对酿酒酵母GJ2008不同糖浓度甘蔗汁酒精分批发酵的影响

研究了不同糖浓度下氮源对酿酒酵母GJ2008甘蔗汁酒精发酵的影响,旨在为高浓度甘蔗汁酒精发酵提供研究基础。将2 g/L尿素加入150 g/L、200 g/L、250 g/L、300 g/L和350 g/L总糖质量浓度甘蔗汁培养基中,以对应糖浓度未添加氮源组为对照组,通过分析细胞生长、糖代谢和乙醇生成来探究氮源如何影响甘蔗汁酒精发酵。结果表明：与未添加氮源相比,氮源加快了发酵速度,发酵周期最高缩短为18 h,糖消耗速率和乙醇生成速率最大分别提高了55%和96%;使酒精发酵更彻底,总糖含量最高减少了40.42 g/L;增加了目的产物,乙醇含量最高提升了28.4%。说明氮源有效地促进了甘蔗汁酒精发酵,加强了酵母的无氧呼吸途径。     

Interactions between yeast, oxygen and polyphenols during alcoholic fermentations: Practical implications

During alcoholic fermentation, even when Saccharomyces cerevisiae cells have used the required oxygen for lipid synthesis, they can consume much more oxygen with no detrimental effect on the fermentation process. Under these conditions, most of the superfluous oxygen is consumed by yeasts by the partial functioning of several nonrespiratory oxygen consumption pathways, which are characterized by the production of reactive oxygen species (ROS). When excess oxygen is added to yeast cells, cell sterol content decreases, following the strong oxidation of intracellular sterols. During aging of fermented products in the presence of nonviable yeast lees (harvested at the end of alcoholic fermentation), the lees can consume oxygen for at least 3 years of the aging process. This oxygen consumption by yeast lees is related to moderate oxidation of yeast membrane lipids by the action of free radicals, strongly decreasing sterols in the yeast lees. The biochemical reactions involved in the oxygen consumption pathways during alcoholic fermentation may be the same as those responsible for oxygen consumption observed in yeast lees. Therefore, the cross-reactivity of complex plant polyphenols, tannins and yeast towards oxygen can easily occur during technological processes (alcoholic fermentation and wine aging). The micro-oxygenation of yeasts releases ROS during alcoholic fermentation and may favour the oxidation of wine phenolic compounds. As yeasts have much higher affinities for oxygen than plant polyphenols, viable yeast and yeast lees compete with phenolic compounds and then hinder the wine aging process. Also, the partial adsorption of plant polyphenols on yeast occurs during alcoholic fermentation, which modifies the overall reactivity of yeast and polyphenols towards oxygen.     

Changes on free amino acids during the alcoholic fermentation of strawberry and persimmon

Changes in amino acids and ammonium were monitored during the alcoholic fermentation of strawberry and persimmon purees. Fermentations were carried out either by autochthonous or by commercial yeasts. The amino acid content in strawberry and persimmon was lower than that of grapes but enough to successfully perform the alcoholic fermentation, showing a different consumption pattern. Arginine, although is not present in the most strawberry substrates, appears in strawberry wines (2.75–3.36 mg L^?1). Additionally, as opposed to grape wine, an exceptional high consumption of proline was observed during the alcoholic fermentation of strawberry purees. The consumption of amino acids was highly influenced by the substrate and the S. cerevisiae strain used for the fermentation process. These results were confirmed by principal component analysis, which was able to group the samples based on substrate, harvest or yeast strain, considering the amino acids as variables.     

Impact of oxygen addition during enological fermentation on sterol contents in yeast lees and their reactivity towards oxygen

During enological fermentations, superfluous oxygen consumption by yeast cells is observed. The superfluous oxygen consumed by the yeast cells is mainly related to the operation of non-respiratory oxygen consumption pathways resulting in an overall decrease in the total sterol fraction in yeast. On the other hand, yeast lees remaining at the end of alcoholic fermentations exhibit specific oxygen utilization rates ranging from 1 to 4 micromol O2 h- 10(-10) cells from the second to the thirteenth month of wine aging. This oxygen consumption capacity of yeast lees was independent of residual cell viability. In this study, we investigated the potential relationship between the oxygen added to commercial yeast strains during enological fermentation and the capacity of the corresponding yeast lees to interact with oxygen. Additions of low (7 mg l(-)) and excess (37 mg l(-1)) amounts of oxygen at the end of the cell growth phase were compared in terms of repercussions on the oxygen consumption activity of the corresponding yeast lees. As expected, the superfluous oxygen consumption by yeast cells during fermentation had a positive influence on the fermentation kinetics and increased cell biomass formation. Oxygen consumption rates and the total capacity of oxygen consumption by the corresponding yeast lees clearly decreased when oxygen was added during fermentation. This marked decrease in yeast lees reactivity towards oxygen was concomitantly related to an increase in ergosterol synthesis and to oxygen-dependent sterol degradation. Such degradation occurred when oxygen was added in excess. Therefore, oxygenation control during fermentation appears to be a potential way to optimize both the fermentation kinetics and control yeast lees reactivity towards oxygen. For practical applications, oxygenation control during alcoholic fermentation may be considered as a general tool for decreasing the highly reductive effect of yeast lees during wine aging.     

有机氮和酵母细胞壁对赤霞珠高糖原料酒精发酵的影响

以高糖度葡萄汁（总糖为286.2 g/L）为发酵原料,对比酵母源有机氮FN502和酵母细胞壁CW101的不同添加时期对葡萄酒酵母酒精发酵速度、乙酸产量、最终酒精度及葡萄糖、果糖残留量的影响。结果表明,在酒精发酵进行1/3时同时添加有机氮FN502和酵母细胞壁CW101（各200 mg/L）,或在酒精发酵进行1/3时添加有机氮FN502（200 mg/L）,进行2/3时添加酵母细胞壁CW101（200 mg/L）,对葡萄酒酵母的酒精发酵速度及果糖消耗促进作用均高于对照及二者分别单独使用,最终酒精度均为16.9%vol,总残糖分别为1.50 g/L和1.58 g/L。有机氮FN502和酵母细胞壁CW101的添加均可显著降低乙酸的产量（P＜0.05）。     

葡萄酒酒精发酵的终止

在葡萄酒酿造过程中,酒精发酵进行的顺利与否对葡萄酒的质量有很大影响。在发酵过程中,多种因素会引起酒精发酵的终止。讨论了引起酒精发酵终止的原因,预防酒精发酵终止的措施以及发酵终止时所要进行的一些处理方法。     

百香果醋生产工艺的研究

对百香果醋研制中的酒精发酵、醋酸发酵过程进行了研究,确定酒精发酵的适宜条件为发酵时间48h,发酵温度32℃,接种量10％;醋酸发酵的最适条件为发酵温度32℃,接种量10％,发酵醪酒精含量6％vol。     

挤压膨化技术应用于木薯生产燃料酒精的初步研究

将木薯挤压膨化后用于酒精发酵,通过单因素试验对木薯挤压膨化酒精发酵的各种影响因素进行了实验研究,并对发酵工艺条件进行了探讨.得出最佳工艺条件:料水比为1:2,糖化酶用量120U/g,糖化时间40min,酵母接种量0.1%.在此条件下,发酵醪酒精体积分数达到15.95%(体积分数).外加氮源对发酵有促进作用,可使发酵醪酒精体积分数达16.25%(体积分数).外加硫酸镁对发酵没有明显影响.     

Study of two wine strains rehydrated with different activators in sluggish fermentation conditions

Rehydration of active dry yeasts is essential in wine fermentation. To help yeast cells withstand the extreme conditions during alcoholic fermentation, adjuvants are added to the must. However, few commercial activators are added directly to the yeast rehydration water, even though this might render hydration more efficient due to a favorable osmotic gradient. The effect of five “metabolic activators” added directly to the water to rehydrate two commercial wine yeast strains in sluggish fermentation conditions was evaluated; these conditions were achieved by acid and osmotic stress. Cell vitality, sugar consumption, glycerol, ethanol and nitrogen contents at 8 and 15 days of process were determined. Furthermore, discrepancy in glucose and fructose consumption was also measured. Ergosterol at certain doses generally showed a favorable effect, so that it could be considered a good activator compared with other molecules involved in essential metabolic cycles.     

番茄醋发酵工艺研究

对以番茄为主要原料，通过酒精发酵和醋酸发酵生产番茄醋的工艺进行了研究。先对番茄原料进行固液混合酒精发酵，然后固液自动分离，分别进行醋酸发酵，整个生产过程只需一套设备。另外确定了最适发酵温度及接种量。