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为研究酵母吸收嘌呤对降低啤酒嘌呤含量的影响,通过检测多种麦汁经酵母发酵后残余嘌呤的含量,分析了酵母对不同存在形式和种类的嘌呤物质吸收能力的差异。研究发现,酵母能且只能利用游离形式存在的嘌呤,其吸收量与游离嘌呤含量显著相关;在一定范围内(游离鸟嘌呤19.8mg/L,游离腺嘌呤20.1mg/L)酵母对游离态嘌呤的吸收率维持在一定水平,超过该范围酵母对游离嘌呤的吸收率下降。该发现对低嘌呤啤酒生产用麦汁中嘌呤物质的处理具有一定指导意义。其可行性通过检测嘌呤核苷磷酸化酶对麦汁核苷的水解效果得到进一步验证。利用酵母对麦汁中嘌呤的吸收特征确实可以降低啤酒中的嘌呤含量。 相似文献
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为了开发一种能水解核苷的嘌呤核苷磷酸化酶(Purine Nucleoside Phosphorylase,PNPase),将其添加到糖化醪液中,增加麦汁中的游离嘌呤碱基质量浓度,在后续发酵阶段游离嘌呤碱基被酵母利用,提高了嘌呤物质的利用率,最终啤酒中的嘌呤质量浓度减少。将PNPase的编码基因deo D导入表达载体pET-28a(+)中,采用化学转化法将载体转入到大肠杆菌BL21(DE3)进行诱导表达,研究重组PNPase的活性,并将其应用到糖化工艺中。获得的重组PNPase活性为184.46 U/mL,添加到糖化醪液中后,麦汁中游离嘌呤碱基质量浓度升高,酵母可吸收的游离嘌呤质量浓度增多,啤酒发酵液嘌呤质量浓度显著降低,为后续研究使啤酒嘌呤含量的降低奠定了一定的基础。 相似文献
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研究旨在探讨啤酒酿造过程中腺嘌呤、鸟嘌呤、次黄嘌呤和黄嘌呤的含量,同时分析其与啤酒发酵常规指标的相关性。以反相离子对色谱法(RP-IPC)分析测定12批次相同浓度啤酒的嘌呤含量,利用数据分析软件spss分析嘌呤含量与啤酒发酵液常规指标的相关性。结果显示,啤酒发酵过程中,游离态嘌呤以黄嘌呤含量最高,其次是鸟嘌呤、腺嘌呤、次黄嘌呤;总嘌呤以鸟嘌呤含量最高,其次是黄嘌呤、腺嘌呤、次黄嘌呤;鸟嘌呤主要以结合态的核苷和核苷酸存在与发酵液中;无论是游离态总嘌呤含量还是总嘌呤含量均与发酵液pH值、还原糖、氨基氮、真浓极显著正相关,与酒精、发酵度极显著负相关;游离态总嘌呤含量与原浓、酵母代时极显著正相关,与酵母细胞数极显著负相关。 相似文献
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有效检测控制啤酒双乙酰含量的要求及措施 总被引:1,自引:0,他引:1
比较了两种检测啤酒中双乙酰的方法,方法二有效、合理,结果准确.提出了从酵母双乙酰还原性能的检测、冷麦汁α-氨基氮的检测、冷麦汁pH值及发酵液pH值的检测等8个检测点进行有效检测控制啤酒双乙酰含量的要求和检测措施. 相似文献
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有效检测控制啤酒中的双乙酰 总被引:4,自引:0,他引:4
双乙酰是衡量啤酒风味成熟与否的决定性指标,其含量超过其味阈值,会给啤酒带来不愉快的馊饭味,影响啤酒风味。两种检测方法比较,以方法二为好。选择的检测点有:(1)酵母对双乙酰的还原性能;(2)冷麦汁、压缩空气、接种酵母、发酵容器、管道等生产环节的微生物;(3)冷麦汁α-氨基氮;(4)冷麦汁pH值和发酵液pH值;(5)接种麦汁溶解氧;(6)酵母接种量;(7)发酵液补加酵母量;(8)清酒及成品双乙酰含量。 相似文献
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本试验检测了添加酒花和不添加酒花,添加低代酵母与高代酵母的麦汁在发酵过程中泡沫的水平。同时检测了麦汁、发酵液及对应的泡沫中总多肽和疏水,陛多肽含量。结果显示发酵液泡沫组分中的总多肽和疏水性多肽含量及泡沫水平与酵母的代数相关。低代酵母(1代或2代)能促进泡沫最大量的形成。同时观察到添加酒花的麦汁比不添加酒花的麦汁发酵过程中形成更多的泡沫,尽管不添加酒花的麦汁中多肽含量较高,可能是因为添加酒花麦汁中的多肽更具有形成泡沫的潜力。本文的结果有利于发酵罐中泡沫的控制,可以不使用添加剂或降低质量来增加产能。 相似文献
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纯生啤酒中残存的蛋白酶A严重影响泡沫稳定性,制约了纯生啤酒的质量提升。为了探索啤酒发酵过程中影响蛋白酶A分泌的因素,作者分别考察了菌种、酵母生理状态、酵母代数、麦汁浓度、发酵时间等对蛋白酶A分泌的影响。结果发现,蛋白酶A分泌量高的菌株,处于稳定期之后的酵母、较高的酵母代数、较高的原麦汁浓度和在发酵阶段末期都会导致发酵液中蛋白酶A活性偏高。建议在实际生产中,采用蛋白酶A分泌量少的菌种、调整酵母生理状态、使用小于3代的酵母、采用18°P以下的麦汁发酵和尽早结束发酵都会对降低蛋白酶A的分泌量起到积极作用。 相似文献
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The preparation of beer‐like beverages with rice malt as the only raw material is reported. Several tests were performed on a laboratory scale and in a 25 L‐capacity pilot plant. Both the decoction and the infusion procedure were tested; malt and water were mixed in a ratio 1:3.5 for both methods and the mash was brewed without adding exogenous enzymes. The obtained worts were fermented using bottom fermenting yeasts, while “beers” were re‐fermented utilizing top fermenting yeasts and adding either sterile wort or sugar. A maximum ethanol of 4.5% vol. was obtained after the primary fermentation from an initial wort with an original gravity of 11.8°Plato. All parameters of the beer were found to be acceptable using a standard beer analysis. Owing to a suitable hop addition, an aroma very similar to that of a normal beer was obtained. 相似文献
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G. G. Stewart C. R. Murray C. J. Panchal I. Russell A. M. Sills 《Food microbiology》1984,1(4):289-302
In order to achieve a beer of high quality, the yeast culture must be effective in removing the desired nutrients from the growth medium (i.e. the wort), it must impart the required flavour to the beer and finally, the micro-organisms themselves must be effectively removed from the fermented wort after they have fulfilled their metabolic role. Brewer's wort contains the sugars sucrose, fructose, glucose, maltose and maltotriose, together with dextrin material. In the normal situation, brewer's yeast strains are incapable of fermenting the dextrin material; however, yeast strains capable of fermenting at least a part of this dextrin material and producing a palatable beer are now available.One of the important factors known to affect the fermentation rate is the intracellular yeast glycogen concentration which has been found to be influenced by storage conditions. The glycogen level at pitching significantly affects the fermentation rate of the yeast culture. 相似文献
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对3-甲硫基丙醛在啤酒中的风味特点及对啤酒麦汁味的影响进行了研究,并对其在啤酒中的阈值进行了测定,研究结果表明啤酒中3-甲硫基丙醛具有类似于谷物蒸煮的味道,描述为麦皮味,与麦汁味相近,且其含量的高低与麦汁味成显著正相关,可以用3-甲硫基丙醛作为表征啤酒麦汁味的指标。经感官品评测定其在啤酒中的差别阈值为5.0μg/L。对样品进行蒸馏萃取结合GC-MS,建立了一种测定麦汁或啤酒中3-甲硫基丙醛的方法,采用外标法定量,该法的相关系数为0.9952,精密度为4.57%,回收率为83.71%~92.48%,检出限为0.015μg/L。应用这一方法检测了不同啤酒中3-甲硫基丙醛的含量,发现普通啤酒都在50μg/L以下,结合其差别阈值,得到啤酒中3-甲硫基丙醛的控制标准为不超过55μg/L。 相似文献
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小麦麦芽在低度啤酒生产中的应用 总被引:1,自引:0,他引:1
在低度啤酒生产中,酿造时添加30%小麦麦芽,30%大麦麦芽,40%大米,采用添加复合酶补充酶活,增加可发酵糖含量,降低麦汁粘度,提高原料利用率;过滤时添加硅胶,提高啤酒非生物稳定性;酵母接种量为原料的0.6%,采用低温发酵;可减少副产物,改善啤酒风味特征;提高社会效益。 相似文献
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分别采用上面发酵工艺与下面发酵工艺进行100%大麦啤酒及100%麦芽啤酒的酿制,并对其麦汁的氨基酸含量、老化Strecker醛、自由基以及新鲜啤酒中老化Strecker醛的含量等进行了对比分析。研究发现,就麦汁而言,100%大麦麦汁中老化Strecker醛的含量都明显低于100%麦芽麦汁;同样的麦汁,上面发酵方式还原Strecker醛的能力明显优于下面发酵方式。就啤酒而言,经酵母还原后,新鲜啤酒中的老化Strecker醛含量较麦汁含量低,且100%大麦啤酒中老化Strecker醛的含量低于100%麦芽啤酒中的含量。100%麦芽麦汁的自由基含量是100%大麦麦汁的近3倍。这都预示着100%大麦啤酒的风味稳定性(新鲜度)明显好于100%麦芽啤酒。 相似文献
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Arabinoxylans are partially water-extractable, high-molecular-weight polymers that contribute to the problems of viscosity and membrane filterability during beer brewing. These problems are more pronounced when wheat and wheat malt are used as adjuncts due to their higher arabinoxylan contents and higher molecular weights. This paper aimed at investigating the effects of mashing temperature, time, grist size and liquor:grist ratio on the solubilization of arabinoxylans. Results indicated that increasing the mashing temperature generally increased the amount of arabinoxylans released into the wort. When greater proportions of wheat or wheat malt were used as adjunct, higher arabinoxylan contents in the final wort were observed. The more finely ground the grist, the more were arabinoxylans released into the wort. When more diluted mashes were used, more efficient solubilization of arabinoxylans was observed. The effects of arabinoxylan content and β-glucan content on the wort viscosity were also examined using a General Linear Model (GLM). There was a good correlation (R2 = 0.98) between wort viscosity and its arabinoxylan and β-glucan contents. 相似文献