四种啤酒浓度检验方法之比较

四种啤酒浓度检验方法为:蒸馏法、折光仪器法、SCABA 仪器法、ANTON PAAR 仪器法。1.原理1.1 蒸馏法通过对定量的除气样品进行蒸馏,对蒸出的酒精接收液进行定容。然后用定容的酒精接收液进行酒精比重测定(酒精比重系指20℃酒精质量与纯水质量的比值),由此查表得出试样中酒精含量的质量百分比,即酒精度,以%(m/m)表示,真正浓度的测定原理与酒精度相同,然后按经验公式计算出样品的原麦汁浓度。     

提高Anton Paar啤酒分析仪的浓度测定精度

目前国内啤酒厂分析啤酒原麦汁浓度普遍使用Anton Paar啤酒分析仪,提高Anton Paar的分析精度能够稳定工艺控制。Anton Paar啤酒分析仪DSA5000的分析原理为:测定U形管中样品的声速变化,通过声速与密度之间特殊的函数关系,得出酒精度和真正浓度,然后通过原麦汁浓度(°P)=(酒精度×2.0665+     

用光度法快速检查桶装啤酒的原麦汁浓度变化

啤酒的原麦汁浓度测定是啤酒厂化验室每天必须检测的项目,是啤酒质量的重要指标之一,也是控制生产成本的关键之一。若原麦汁浓度偏高,啤酒的成本增加;但偏低,甚至低于标准下限,则会影响啤酒口味而成为不合格品。目前化验室常用重量法分别测定酒精度和真正浓度,通过公式计算而求得原     

对我国啤酒标准及其试验方法的几点看法

自1986年起,全国生产啤酒的厂家几乎都采用国标GB4927—85、GB4928—85和部标QB936—84;通过几年来的实践,我们认为这些标准都有不够完善的地方,有待进一步修订,我们认识到的有下列几方面:(一)标准中对酒精度和真正发酵度只需规定其中一项即可。因为这两个指标是有因果关系的,确定的原麦汁浓度和发酵度,酒精度就是必须要达到的必要条件;反过来,在一定的原麦汁浓度和酒精度下,啤酒的发酵度是计算所得的必然结果。以12°啤酒为例,标准中规定酒度≥3.7%,原浓为11.80—12.20%,发酵度≥60%;若酒精度     

高浓高温对啤酒酵母发酵性能的影响

以啤酒酵母S-6为实验菌株,研究了主发酵温度和原麦汁浓度对啤酒发酵的残糖、酒精度、风味物质和絮凝性等性能指标的影响。结果表明,原麦汁浓度一定时,主发酵温度对高级醇和乙酸酯的含量影响较大,主发酵温度由10 ℃提高至16 ℃时,高级醇含量提高了10%～20%,乙酸酯含量提高了8%～16%,但CO2累积质量损失、残糖、酒精度和絮凝性基本不受温度的影响;主发酵温度一定时,原麦汁浓度对酵母絮凝性影响较大,原麦汁浓度越高,酵母絮凝性越低,将高浓（18 °Bx）发酵液稀释50%至常浓（12 °Bx）,残糖、酒精度和高级醇的含量与常浓发酵液基本相同。该研究为选育高温高浓发酵低产高级醇同时强絮凝性酵母菌株提供了重要依据。     

低度强化啤酒的研究

“低度强化啤酒”是指酒精度和原麦汁浓度低,用赖氨酸强化的新型啤酒。低度啤酒,因酒精度低,颇受群众欢迎,同时,由于麦汁浓度低,耗粮少,生产周期短,可以扩大原有设备的生产能力,大幅度增加产量,降低成本,提高经济效益。因此,低度啤酒在国内外正在发展之中。     

啤酒酒精度重量法和容量法测定结果的一致性

关于啤酒中酒精度用 m/m 和 v/v 表示,我们在计算原麦汁浓度等指标时,需要酒精的重量百分比(m/m),而体积比(v/v)只能通过计算求出。我做过一次实验,就是用同一个啤酒,分别称100g 和另取100mL 加50mL 蒸馏水,同时蒸馏,(馏     

浸入式折光计测定啤酒原麦汁浓度

本文叙述用浸入式折光计测定啤酒的原麦汁浓度具有快速、准确、连续测定的优点。通过实例,对折光法与蒸馏法进行了比较。     

两酒一粉抽样百分百合格

近期，北京市质量技术监督对北京市8家企业生产的8种啤酒和葡萄酒产品，2种乳粉和1种干酪产品进行了监督抽查，产品抽样合格率为100％。本次抽查啤酒检验项目包括酒精度、原麦汁浓度和双乙酰等，葡萄酒的检验项目包括酒精度、总糖、干浸出物和二氧化硫等。本次抽查的8种产品全部合格。     

不同啤酒生物胺含量的比较

使用反相高效液相色谱法,测定啤酒中8种常见生物胺含量。以苯甲酰氯为衍生试剂,Agilent EclipseXDB-C18为固定相,乙腈和乙酸铵溶液为流动相,紫外检测波长设置为254 nm,梯度洗脱。本文首先对国内市售啤酒生物胺种类及含量范围进行研究,检测结果表明国内啤酒中8种生物胺均有存在,但不同样品所含种类不同,且有个别胺含量偏低无法定量。不同厂家的产品在种类和含量上存在差别,但整体含量接近,生物胺总量为4.21～10.59 mg/L,不足以对人类健康产生危害。原麦汁浓度、酒精度与生物胺含量的关系显示,二者与生物胺有一定联系,但非主要因素,相对于生产厂家和发酵情况,原麦汁浓度、酒精度对生物胺含量的影响较小。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press