Simultaneous determination of carbohydrates and organic acids in beer and wine by ion chromatography

The simultaneous determination of mono-organic acids and carbohydrates by ion chromatography with both conductometric and pulsed amperometric detection is described. The carbohydrates, such as mannitol, arabinose, glucose, fructose, lactose, sucrose, raffinose, and maltose, as well as monoorganic acids including acetate, glycolate, formate, pyruvate, and fluoride are separated as anions by ion-exchange chromatography with 0.080 mol/L sodium hydroxide eluent at 1 mL/min within 12 min. Carbohydrates are determined by pulsed amperometric detection and mono-organic acids are determined by suppressed conductivity detection. The species in beverages are determined.     

Melatonin in Wine and Beer: Beneficial Effects

Melatonin is a hormone secreted in the pineal gland with several functions, especially regulation of circadian sleep cycle and the biological processes related to it. This review evaluates the bioavailability of melatonin and resulting metabolites, the presence of melatonin in wine and beer and factors that influence it, and finally the different benefits related to treatment with melatonin. When administered orally, melatonin is mainly absorbed in the rectum and the ileum; it has a half-life of about 0.45–1 h and is extensively inactivated in the liver by phase 2 enzymes. Melatonin (MEL) concentration varies from picograms to ng/mL in fermented beverages such as wine and beer, depending on the fermentation process. These low quantities, within a dietary intake, are enough to reach significant plasma concentrations of melatonin, and are thus able to exert beneficial effects. Melatonin has demonstrated antioxidant, anticarcinogenic, immunomodulatory and neuroprotective actions. These benefits are related to its free radical scavenging properties as well and the direct interaction with melatonin receptors, which are involved in complex intracellular signaling pathways, including inhibition of angiogenesis and cell proliferation, among others. In the present review, the current evidence on the effects of melatonin on different pathophysiological conditions is also discussed.     

A Metabolomic Approach to Beer Characterization

The consumers’ interest towards beer consumption has been on the rise during the past decade: new approaches and ingredients get tested, expanding the traditional recipe for brewing beer. As a consequence, the field of “beeromics” has also been constantly growing, as well as the demand for quick and exhaustive analytical methods. In this study, we propose a combination of nuclear magnetic resonance (NMR) spectroscopy and chemometrics to characterize beer. ¹H-NMR spectra were collected and then analyzed using chemometric tools. An interval-based approach was applied to extract chemical features from the spectra to build a dataset of resolved relative concentrations. One aim of this work was to compare the results obtained using the full spectrum and the resolved approach: with a reasonable amount of time needed to obtain the resolved dataset, we show that the resolved information is comparable with the full spectrum information, but interpretability is greatly improved.     

啤酒酵母中β-(1-3)葡聚糖的提取及其性能分析

本文采用Sevage脱蛋白法、酸溶液浸提法、碱溶液浸提法对啤酒废酵母细胞壁中的β-(1-3)葡聚糖作了提取试验,并对所获多糖进行生化特性分析,阐述了碱溶液浸提法是从啤酒酵母中回收高质量β-(1-3)葡聚糖的理想途径．     

High gravity batch and continuous processes for beer production: Evaluation of fermentation performance and beer quality

This study deals with two innovative brewing processes, high gravity batch and complete continuous beer fermentation systems. The results show a significant influence of the variables such as concentration and temperature on the yield factor of the substrate into ethanol and consequently on the productivity of the high gravity batch process. The technological feasibility of continuous production of beer based on yeast immobilization on cheap alternative carriers was also demonstrated. The influence of process parameters on fermentation performance and quality of the obtained beers was studied by sensorial analysis. No significant difference in the degree of acceptance between the obtained products and some traditional market brands was found. Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May 2007.     

辛巴蓝F-3GA修饰的啤酒废酵母菌亲和吸附溶菌酶

利用j嗪染料辛巴蓝F-3GA修饰经戊二醛交联的啤酒废酵母菌,得到一种新型染料亲和吸附剂.辛巴蓝F-3GA的固载量为161.1 mg/g.以溶菌酶为研究对象,考察吸附时间、酶初始浓度、pH值、离子强度等因素对吸附率的影响.结果表明:当pH=7.0时,其对溶菌酶有较高的吸附量(229.1 mg/g),吸附性能明显优于未接枝...     

在线原麦汁浓度检测仪

原麦汁浓度是啤酒生产过程中的一项重要指标。溶液的折射率是其浓度的函数 ,全反射的临界角与其浓度之间有一一对应关系。利用线阵CCD做为高精度探测器件 ,检测全反射临界角的变化 ,可测量溶液的浓度。临界角的变化与电源的波动及光源的强度变化等因素无关 ,并且溶液中的固体颗粒、小气泡等不影响检测精度。研制了一种在线检测原麦汁浓度的测试仪器 ,介绍了仪器的光学结构及数据处理方法。现场测量精度为± 0 1(以浓度表示)     

Microrobots in Brewery: Dual Magnetic/Light-Powered Hybrid Microrobots for Preventing Microbial Contamination in Beer

Yeasts play a key role in the production of alcoholic beverages by fermentation processes. However, because of their continuous growth, they commonly cause spoilage of the final product. Herein, we introduce dual magnetic/light-responsive self-propelled microrobots that can actively move in a beer sample and capture yeast cells. The presence of magnetic nanoparticles on the surface of the microrobots enables their magnetic actuation under fuel-free conditions. In addition, their photoactivity under visible-light irradiation leads to an overall enhancement of their swimming and yeast removal capabilities. It was found that after the application of the microrobots into a real unfiltered beer sample, these micromachines were able to remove almost 100 % of residual yeasts. In addition, these microrobots could also be added at the initial step of the fermentation process without altering the final beer properties, such as alcohol level, color, and pH. This work demonstrates the potential of using externally actuated microrobots as an innovative and low-cost solution for avoiding yeast spoilage in complex liquid environments, such as alcoholic beverages. Therefore, these autonomous self-propelled microrobots open new avenues for future applications in the food industry.     

高中化学“物质转化及反应调控”项目式学习*——我是米酒酿造师

以“我是米酒酿造师——如何在家中酿造出美味可口的米酒”为项目主题,在化学、生物学科融合的大背景下,开展“物质转化及反应调控”的教学。通过“了解米酒酿造的原理、探究米酒酿造的影响因素、设计米酒酿造的方案”等3个核心活动,落实典型有机化合物的性质、有机化合物之间的转化等核心知识;在解决实际问题的过程中体会控制变量思想在科学探究中的重要作用,体会调控化学反应的速率和限度的重要意义。     

离子转换色谱-紫外检测法测定啤酒中的无机阴离子和有机酸

建立了离子转换色谱与紫外检测器联用检测啤酒中无机阴离子与有机酸的新方法。在传统的离子色谱基础上引入两根离子转换柱,无机阴离子与有机酸经过两步转换,定量转换成有相同紫外响应的碘酸盐,然后用紫外检测器代替电导检测器进行定量分析。在Dionex AS11-HC阴离子色谱柱上,采用KOH梯度淋洗方式实现了12种无机阴离子与有机酸的分离。结果表明,12种无机阴离子和有机酸检出限（S/N=3）与定量限（S/N=10）分别为6.168~29.01 μg/L与20.56~66.30 μg/L;线性关系良好（r在0.9994以上）,回收率为89.0%~117.0%,RSD均小于1.0%,该方法与传统的电导检测器检测结果相当。该方法简单快捷,只需采用少数标准曲线,就可以实现啤酒中无机离子与有机酸的定量测定。