比色法测定啤酒中的草酸含量

本文研究利用三氯化钛溶液与草酸的显色反应定量分析啤酒中的草酸，研究了三氯化钛与草酸反应的最佳显色条件及测定过程的预处理方法。测定结果表明：用氯化钙沉淀啤酒或麦汁样品中的草酸，再用稀盐酸溶解草酸的方法，能够消除样品的干扰，实现比色法定量分析草酸；预处理过程草酸丢失极少，平均回收率可达95％。     

控制啤酒中残留草酸含量的探讨

通过对酿造原料（包括麦芽、大米、酒花）的考察，发现不同的麦芽品种中草酸含量各不相同，酒花对麦汁中的草酸含量影响较大，添加辅料大米有助于降低草酸，酵母发酵对草酸含量影响很小。当麦汁中的钙离子含量达到80mg／L时，啤酒中的钙离子浓度在60mg／L，啤酒中的草酸15mg／L左右。     

啤酒中草酸含量的测定

对HPLC法、分光光度法和荧光光度法测定啤酒中草酸含量的实验条件进行了比较和优化,实验结果表明,HPLC法和分光光度法的实验重复性较好,回收率较高,检测范围较宽,能较好地满足实际检测的需要,但HPLC法对实验设备的要求较高,而分光光度法不适合于要求较高的场合.荧光光度法由于检测限较低,非常适合于低草酸含量啤酒(如加钙啤酒)的测定.     

荧光法测定啤酒中的草酸

利用在硫酸介质中,草酸能催化重铬酸钾氧化罗丹明B褪色,使体系荧光猝灭,建立了催化荧光法测定草酸的方法,催化反应在50℃水浴中进行10min,测定草酸的线性范围为0．4～12．0mg/L,其回归方程为△F=17．423c（mg／L）＋110．47,γ=9994。此法用于啤酒中草酸含量的测定,结果满意。     

荧光法测定啤酒中牛磺酸含量

以啤酒为基质,牛磺酸为添加剂,采用强酸性阳离子交换柱分离出牛磺酸,与邻苯二甲醛(OPA)/2-巯基乙醇衍生化后进行荧光法测定。结果表明:相对标准偏差≤2.4%,回收率>95%,最小检出限为0.023μg/mL;放置6个月的和现配的样品中牛磺酸含量差别无显著性(p>0.05)。该方法快速、简便而且重现性好,可用于测定啤酒中添加的牛磺酸。     

啤酒中酒精及其含量的测定

啤酒中酒精及其含量的测定韩波赵忠森孙慧（佳木斯啤酒厂）（绥滨啤酒厂）（黑龙江省轻工业研究所）啤酒发酵是一个非常复杂的生化过程。酵母的发酵作用，主要是利用麦汁中所含的麦芽糖、葡萄糖和麦芽三糖等可发酵性的糖类，经过一系列的生物化学反应的作用，生成酒精和二...     

反相高效液相法和荧光光度法测定啤酒中草酸含量的应用和比较

对HPLC法、分光光度法和荧光光度法测定啤酒中草酸含量的实验条件进行了优化和比较.结果表明,HPLC法和分光光度法实验重复性较好,回收率较高,检测范围较宽,能较好满足实际检测的需要,但HPLC法对实验设备的要求较高,而分光光度法不适合于要求较高的场合.荧光光度法由于检测限较低,非常适合于低草酸含量啤酒(如加钙啤酒)的测定.     

浅谈啤酒中铁含量的测定

众所周知,啤酒酿造用水是指糖化用水、洗糟用水和高浓酿造稀释用水。在投产前的原材料检验时,水质的检验也很重要,水中铁含量达标,酿造出的啤酒铁含量也符合要求,但这并不是绝对的,因为有时水中铁含量很低,酿造的啤酒铁含量却很高,这是什么原因呢？我们考虑除了麦...     

保健酒中草酸含量检测方法研究

建立保健酒中草酸含量的检测方法。选用ZORBAX SB-Aq柱（4.6 m×250 mm,5μm）,以磷酸二氢钾的水溶液（pH3.2）为流动相进行洗脱,流动相流速为0.80 mL/min;柱温箱温度为30℃;进样量为10μL;紫外检测器检测波长为220 nm。草酸在27.72～887.16 mg/L范围内呈良好的线性关系,相关系数R=0.9999,平均加样回收率102.87%,RSD=2.45%（n=6）。该方法简便、准确,重复性好,精密度高,可用于保健酒中草酸的质量控制。     

降低啤酒中乙酸含量的初步研究

啤酒中的乙酸主要来自麦芽及发酵过程。不同品种和制麦工艺制作的原料麦芽中乙酸含量有较大差异。麦汁浓度与麦汁pH值的升高均使乙酸增加，尤以后者的影响更显著。发酵前期，乙酸含量不断减少，在后酵过程中到达最低值后缓慢上升，最后趋于稳定。另外，在保证煮沸麦汁质量的前提下，增加煮沸时间和强度能大量减少乙酸含量。空气洗涤处理对麦汁中乙酸量的降低也有明显影响。     

Ascorbic Acid Stability in Ground Asparagus Samples and in Oxalic Acid Extracts

To establish the storage conditions for asparagus preparation before ascorbic acid determination, samples were ground, the mass was divided into three aliquots that were, respectively, stored at 4°C, – 18°C, or extracted with 1% oxalic acid. The extract was further split into aliquots and stored at 25°, 4°, –18° and -75°C. Ascorbic acid content was measured at different times of storage by a polarographic method. The rate of degradation increased with storage temperature; the degradation rate was higher in ground samples than in extracts; no significant changes in ascorbic acid content were observed in extracts stored for 7 days at -18° or for 90 days at -75°C.     

亚麻织物草酸酸洗加工工艺技术的研究

对亚麻织物前处理工艺中草酸酸洗工序进行了研究。通过正交试验筛选了工艺条件，确定了草酸酸洗的生产工艺，并对此进行了讨论：酸洗是亚麻织物前处理工艺中的重要工序，酸洗主要是利用草酸洗除亚麻织物中的铁、锰离子等杂质，减少双氧水的剧烈分解，起到降低亚麻织物强力损失的作用。     

The Oxalic Acid Content in Selected Barley Varieties Grown in Poland,as well as in their Malts and Worts

The purpose of this work was to try to answer the question “What factors influence the oxalic acid content in barley, malt and wort?” Samples of three malting barley varieties (Prestige, Sebastian and Jersey, registered and grown in Poland) were investigated for their oxalic acid content. Laboratory scale malting and kilning of these samples and investigation of their oxalic acid content were conducted. Furthermore, the oxalic acid content was analysed in worts obtained from these malts. Tested barley samples, originating from various regions of Poland, showed different oxalic acid contents, ranging from 17.2 to 66.8 mg/kg d.m. basis. A higher temperature of germination (an increase from 14°C to 18°C with the same length of time) resulted in a decrease in oxalic acid content in the resultant worts. In most cases a positive linear correlation was found between the oxalic acid content in the malts and worts, and the initial barley samples. Oxalic acid content in barley appears to depend on the growth region rather than on the variety, but the data was not sufficient to draw any firm conclusions on this subject.     

氧对啤酒质量的影响及预防啤酒氧化的措施

该文简述了氧对啤酒质量的影响,影响啤酒的非生物稳定性,改变啤酒的风味及颜色。并就过滤和灌装环节提出了预防啤酒氧化的措施。     

啤酒总酸测定方法的改进

考察了不同脱气方法对啤酒总酸度测定的影响,建立了利用抽真空快速脱气的方法.实验结果表明,对未进行任何处理的啤酒样品振摇抽真空5 min,可以有效脱去啤酒中的CO2,简化了啤酒样品的预处理过程,从而极大地缩短了测定啤酒中总酸度的总的分析时间.将该方法用于啤酒总酸的测定,啤酒总酸度的相对平均偏差为0.06%(n=8).     

Beer with Reduced Ethanol Content Produced Using Saccharomyces cerevisiae Yeasts Deficient in Various Tricarboxylic Acid Cycle Enzymes

A collection of Saccharomyces cerevisiae strains deficient in the tricarboxylic acid cycle enzymes activities has been examined for the production of beer with reduced ethanol content. Strains deficient in fumarase and α‐ketoglutarate dehydrogenase encoded by the genes FUM1 (0.48%), KGD1 (0.42%) and KGD2 (0.48%) made non‐alcoholic beers with an alcohol content lower than 0.5% (v/v). The rest of the yeast mutants also gave rise to low‐alcoholic beers but with a slightly elevated ethanol concentration (mostly in the range of 0.57‐0.84% and 1.64% for the lip5 mutant). Low ethanol content was compensated by the considerable increase of organic acids (citrate succinate, fumarate, and malate). In addition, some of the mutants released high levels of lactic acid (144 fum1), 622 (kgd1) and 495 (kgd2) mg/L). Lactic acid protects beers against contamination and masks an unacceptable worty off‐flavour.     

草酸对桃贮藏期抗性相关酶活性的诱导

以栽培品种“皮球桃”为试材,采后以草酸溶液浸泡处理后,置于温度为(1 ± 1)、(4 ± 1)、(8 ± 1)℃的气调库贮藏,测定贮藏过程中部分抗性酶的活性以及丙二醛的含量,探讨草酸、温度等对气调贮藏条件下的皮球桃采后抗性生理的影响。结果表明：与对照组相比,草酸处理能提高桃果SOD、CAT 的活性,在贮藏中后期提高PPO 的活性,对POD 没有直接影响,并使MDA 的积累得到控制。以草酸(1 ± 1)℃的处理组的效果最为明显,说明草酸和低温能在一定程度上提高桃果实的抗性。