酶标仪比色法检测浊米酒中高级醇含量

为探索酶标仪比色法在浊米酒高级醇含量检测中的适用性,该研究建立了酶标仪比色法检测浊米酒中6种高级醇(异丁醇、异戊醇、苯乙醇、正丙醇、正丁醇、己醇)的单一和混合标准曲线,并对比了酶标仪比色法和气相色谱法对浊米酒中高级醇含量的检测效果。结果表明,酶标仪比色法建立的混合标曲在0~0.05 mg线性均较好,单一标曲中正丙醇在0~1 mg线性较差,而苯乙醇和正丁醇在0~0.05 mg线性稍差,并在一定程度上影响其他高级醇检测效果;酶标仪比色法测得FBKL2.8022和FBKL2.8023发酵米酒中6种高级醇的质量浓度分别为408.94 mg/L和230.89 mg/L,其中6种高级醇含量的标准偏差分别为0.06%~3.94%和0.72%~1.58%,酶标仪比色法测定结果高于气相色谱法。该研究使用酶标仪比色法检测发酵米酒中不同高级醇的含量,发现高级醇配比不同会影响标准曲线的线性方程和相关系数,因此需要根据样品检测需求而选择合适配比的标曲进行样品检测分析。     

白酒中微量尿素快速测定方法研究

对二乙酰一肟比色法测定尿素含量的反应条件进行了优化,并对白酒样品预处理方法进行了研究,建立了一种快速测定白酒中尿素的方法。白酒样品经80℃旋转蒸发至干,加入一定量的蒸馏水将残留物洗出;洗出液通过0.22μm膜过滤后测定尿素含量。比色反应的最适条件为水浴温度90℃,反应时间30 min。结果表明,该法测定白酒中尿素含量在0～4 mg/L范围内线性关系良好,R2为0.999;RSD值为3.52%,加标回收率为96.7%～105.8%之间。该方法具有快速方便、定量准确等优点,适合白酒中尿素的检测。     

高效液相色谱法检测枯草芽孢杆菌发酵液中乙偶姻和2,3-丁二醇含量

枯草芽孢杆菌可发酵代谢产生乙偶姻和2,3-丁二醇(两者可逆转化),本研究建立了用高效液相色谱法同时检测发酵液中乙偶姻和2,3-丁二醇的方法。对比了不同色谱柱和流动相配比对乙偶姻和2,3-丁二醇含量的测定结果,进一步检测枯草芽孢杆菌发酵液中乙偶姻和2,3-丁二醇含量。结果表明:采用Bio-Rad Aminex HPX-87H Column分析;流动相:0.005 mol/L的硫酸溶液;流速:0.5 mL/min;柱温:28℃;示差检测器,在30 min内完成样品检测,乙偶姻和2,3-丁二醇标准曲线相关系数分别为0.9997和0.9998,精密度标准偏差分别为1.76%和1.74%,稳定性标准偏差分别为1.2%和1.6%,回收率为98.93%~102.10%,相对标准偏差≤ 2%。此方法简单准确,检测目标物浓度为50 g/L,检测结果重现性好,发酵液中乙偶姻和2,3-丁二醇含量呈负相关,乙偶姻的含量随着2,3-丁二醇的增加而降低,该方法适合枯草芽孢杆菌发酵液中乙偶姻和2,3-丁二醇的发酵检测。     

便携式近红外甲醇检测仪与实验室仪器预测能力比较

目的探究联合研发便携式近红外检测仪检测白酒基酒中甲醇含量的可行性。方法分别用比色皿、液体探头取样检测白酒基酒中甲醇的含量,借助化学计量学方法建立白酒中甲醇含量的预测模型,并与实验室VECTOR33型近红外光谱仪所建模型的预测能力进行比较。结果校正集决定系数分别为:0.819、0.838、0.886,校正标准差分别为:16.13、15.78、14.60mg/L,验证集的决定系数分别为:0.814、0.820、0.844,预测标准差分别为:19.99、19.25、20.44 mg/L,平均相对误差分别为:8.94%、8.32%、9.34%。结论研发的便携式近红外检测仪与实验室仪器的检测结果具有较好的一致性,可以用来检测白酒基酒中甲醇含量。     

高产乙偶姻酵母菌种的选育与提高白酒中四甲基吡嗪含量的研究

四甲基吡嗪是近年来在白酒中发现的一种健康因子,提高白酒中四甲基吡嗪的含量对于白酒产品风味与品质具有重要影响。总结了白酒中四甲基吡嗪的形成途径以及目前的研究进展,酿酒酵母细胞中的乙偶姻代谢与调控机制,并通过分子育种手段选育了一系列高产乙偶姻的酵母菌株。在清香型麸曲白酒中的应用结果表明,与出发菌株比较,高产乙偶姻菌株在固态厌氧发酵条件下的基本发酵性能没有发生变化,酒醅中乙偶姻的含量提高达320.38%,TTMP的含量提高了74.66%。     

我国白酒蒸馏过程及原酒、成品酒中乙醛的研究

乙醛广泛存在于酒精饮料中,被国际癌症研究机构(IARC)确认为Ⅰ类致癌物(对人类致癌证据充分)。利用气相色谱-氢火焰离子化检测(GC-FID)技术检测我国馏分酒、原酒和成品白酒中乙醛,发现白酒固态蒸馏和液态二次蒸馏过程中乙醛和乙缩醛很快被馏出,含量较集中于前几个馏分,随着蒸馏进行,含量逐渐减少。原酒中乙醛质量浓度在45.10~763.93 mg/L,乙缩醛的质量浓度在61.50~2 871.52 mg/L,乙缩醛和乙醛的比例在2.26∶1~2.87∶1。成品白酒中乙醛质量浓度42.36~491.70 mg/L,乙缩醛的质量浓度在68.54~811.32 mg/L,乙缩醛和乙醛的比例在1.24∶1~1.96∶1,且成品白酒乙醛的平均质量浓度(173.24 mg/L)高于其他国家蒸馏酒中乙醛的质量浓度(≤86 mg/L)。我国成品白酒中乙醛的暴露边界(margin of exposure,MOE)值为622,因此白酒中乙醛对人类健康的潜在危害应给予较高关注。     

酱香大曲中高产四甲基吡嗪微生物的选育及应用研究

为了选育得到高产四甲基吡嗪的功能微生物以提高酱香白酒中四甲基吡嗪含量,本研究采用富集培养、Voges-Proskauer(V-P)反应实验、蛋白酶透明圈实验结合发酵实验从酱香大曲中筛选得到乙偶姻、蛋白酶和四甲基吡嗪产量高的微生物,并将其应用于酱香大曲模拟生产。经过V-P反应实验和蛋白酶透明圈实验从富集培养得到的微生物中初筛到6株高产乙偶姻和蛋白酶的微生物,再经发酵实验进一步筛选到1株四甲基吡嗪产量表现优异的微生物△JYF1,达到424 mg/L,对其进行形态学观察和分子生物学鉴定确定为西姆芽孢杆菌（Bacillus siamensis）。菌株△JYF1应用于酱香大曲模拟生产时,发酵产物中四甲基吡嗪产量可以达到65.51 mg/kg,还具有浓郁的酱香味。     

芽孢杆菌与酵母菌和根霉曲混合发酵提高四甲基吡嗪含量的研究

四甲基吡嗪(Tetramethylpyrazine,TTMP)是白酒中一种重要的香气成分,提高大曲中四甲基吡嗪的含量对提高白酒中四甲基吡嗪的含量具有重要意义。本研究通过芽孢杆菌纯种发酵(A);同时接种酵母菌和芽孢杆菌(B);先接种酵母菌,再接种芽孢杆菌(C);先接种酵母菌和根霉曲,再接种芽孢杆菌发酵(D),测定发酵结束后4组实验四甲基吡嗪,乙偶姻和氨含量,还原糖和酸度变化。结果表明,D组四甲基吡嗪含量最高,为881.5μg/g,C组低于D组,为493.9μg/g,A组和B组低于C组,分别为293.6μg/g和150.1μg/g。前体物质乙偶姻和氨的变化相似,C组和D组乙偶姻含量为150.1 mg/g和140.4 mg/g,高于A组(99.4 mg/g)和B组(61.8 mg/g)。C组(5.7 mg/g)和D组(5.3 mg/g)氨含量也高于A组(4.4 mg/g)和B组(3.6 mg/g)。C组和D组还原糖高于A组和B组,酸度也较高于A组和B组。本研究为多菌株协同发酵提高白酒中四甲基吡嗪的含量奠定了基础。     

豉香型白酒中乙缩醛的色谱分析及应用

利用岛津GC17A气相色谱及惠普HP-101（Methyl Siloxane）19091Y-015型毛细管柱,FID检测器,以乙酸正戊酯为内标,对豉香型白酒中的乙缩醛和乙醛进行检测。实验结果表明,乙缩醛的相对标准偏差少于2%（n=6）,线性范围为0～400mg/L,r=0.99975。方法简单、准确、重现性好。用该方法对豉香型白酒产品进行乙缩醛含量检测,对豉香型白酒生产工艺以及勾兑有重要的指导作用。     

山西老陈醋两种风味物质含量变化分析

对山西老陈醋酒精发酵、醋酸发酵、熏醅阶段样品中乙偶姻(ACT)和川芎嗪(TMP)含量进行了测定分析。结果表明:乙偶姻最早产生于醋酸发酵阶段,其含量在醋酸发酵和熏醅阶段呈先上升后下降的趋势;川芎嗪最早产生于熏醅阶段,并在此阶段大量富集;熏醅阶段同一批次样品中乙偶姻含量逐渐减少而川芎嗪含量逐渐增多,不同批次样品中川芎嗪含量并不随着乙偶姻含量的增加而增加,初步推测乙偶姻与氨气反应是川芎嗪生成的一种途径,但不是唯一途径。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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