毛细管电泳-电化学检测测定荞麦中表儿茶素、芦丁、槲皮素的含量

用毛细管电泳-电化学检测的方法研究了荞麦中黄酮类物质:表儿茶素、芦丁、槲皮素的含量,研究了电极电位、缓冲液的pH值、分离电压及进样时间对电泳的影响,得到优化的测定条件。以直径为300μm的碳圆盘电极为检测电极,工作电极电位为0.95V(vs.SCE),在50mmol/L硼砂(pH8.5)运行缓冲液中,上述3组分在12min内完全分离。表儿茶素、芦丁、槲皮素线性范围分别为5×10-7￣1×10-4g/mL、1×10-6￣1×10-4g/mL、1×10-6￣1×10-4g/mL;检出限分别为1.83×10-7g/mL、2.9×10-8g/mL、1.00×10-7g/mL;3种标样7次平行进样的相对标准偏差(RSD)小于2.5%;回收率表儿茶素100.4%、芦丁98.1%、槲皮素100.1%(n=3)。该法灵敏可靠,结果令人满意。     

高效毛细管电泳法检测橘皮中橙皮苷的含量

应用毛细管电泳法对橘皮中橙皮苷的含量进行了检测,研究了缓冲液的种类、缓冲液的浓度、缓冲液的pH值以及分离电压等对橙皮苷测定的影响。在pH8.0的150 mmol/L硼砂缓冲液、12 kV分离电压下,橙皮苷的测定效果最佳。毛细管电泳法测定橙皮苷的最低检测限为1.25μg/mL,加样回收率是99.75%,相对标准误差是1.98%。     

毛细管电泳-电化学发光分离检测饮料中L-赖氨酸

目的:根据L-赖氨酸(L-lysine)具有增强三联吡啶钌(Ru (bpy)32+)电化学发光信号的特性,建立一种毛细管电泳-电化学发光分离检测L-赖氨酸的新方法.方法:研究检测电位、Ru(bpy)32+浓度、进样时间、进样电压、分离电压和缓冲液pH等试验参数对L-赖氨酸检测的影响.结果:在最佳试验条件下,检测电位1.13 V;Ru( bpy)32+浓度7 mmol/L(pH 8.5);进样时间10s;进样电压12 kV;分离电压12 kV;磷酸盐缓冲液pH 8.5,8 min内可实现L-赖氨酸的分离检测,线性范围3.00～87.00 μg/mL,相关系数R=0.9991,检出限(S/N=3)为0.21μg/mL.对样品进行测定,电化学发光强度和迁移时间的RSD分别为3.85％和0.66％(n=6).结论:本法已成功用于饮料中L-赖氨酸的检测,结果令人满意.     

毛细管电泳检测发酵液中1,3-二羟基丙酮方法的建立

建立了利用毛细管电泳(CE)技术快速、准确检测发酵液中1,3-二羟基丙酮含量的新方法。所用熔融石英毛细管规格为50μm×60 cm(有效长度为45 cm),分离电压为24 kV,缓冲液为pH9.5的30 mmol/L硼砂缓冲溶液,200 nm处检测DHA。结果表明,DHA标准样品的迁移时间为8.3 min,在100μg/mL～1 000μg/mL范围内线性关系良好(R2=0.999 5),加样回收率为97.79%,RSD为1.81%。测得以甘油作为底物发酵产DHA发酵液中DHA含量为3.220g/L,此方法可有效应用于产DHA发酵过程中产物的检测。     

微乳毛细管电动色谱法检测鸡精中的3种氯丙醇

建立了微乳毛细管电动色谱分离检测3种氯丙醇的方法。考察了表面活性剂十二烷基硫酸钠(SDS)浓度、缓冲液pH及浓度、有机添加剂、助表面活性剂浓度、温度和运行电压对3-氯-1,2-丙二醇(3-MCPD)、1,3-二氯-2-丙醇(1,3-DCP)和2,3-二氯-1-丙醇(2,3-DCP)分离的影响。结果表明,最佳的微乳液组成为:3.31%(w/v)SDS,6.61%(w/v)正丁醇,0.81%(w/v)正辛烷,10%(v/v)乙腈,79.3%(v/v)5 mmol/L磷酸盐-硼砂缓冲液(pH9.0)。该微乳体系中有机溶剂乙腈对氯丙醇的分离起到了重要作用。当分离电压为20 kV、分离温度为20℃、检测波长192 nm时,3种氯丙醇在16 min内达到基线分离。3-MCPD的线性范围为2.5～500μg/mL,1,3-DCP和2,3-DCP的线性范围均为1.0～500μg/mL,相关系数均大于0.998,检出限(S/N=3)分别为0.5、0.4、0.5μg/mL。该法操作简单,灵敏度高,实验结果准确可靠,用于鸡精样品中3种氯丙醇的同时检测,结果满意。     

毛细管电泳安培检测法快速测定巧克力中的香兰素

运用毛细管电泳安培检测法研究了巧克力中香兰素的快速测定方法,研究了电极电位、缓冲液的浓度和pH、分离电压以及进样时间等因素对分离测定的影响。在30mmol/L的硼砂(pH9.24)运行缓冲液中,施加15kV的分离电压及 0.65V(vs.SCE)的电极电位条件下,铜电极对香兰素有很好的响应。香兰素在5.0×10-6～1.0×10-3g/mL范围内存在较好的线形关系,检测限为3.87×10-7g/mL(S/N=3)。对实际样品的测定,回收率为96.5%～102.8%,结果令人满意。     

毛细管胶束电动色谱分离测定大米中水胺硫磷和灭多威的残留量

用毛细管胶束电动色谱成功地分离了2种农药：水胺硫磷和灭多威。研究了电泳缓冲液的pH、浓度及表面活性剂浓度等影响因素,在选定的最佳分离条件：pH7.0,20mmol/L硼砂缓冲溶液＋70mmol/LSDS＋20%甲醇,20kV分析电压,检测波长214nm下,二组份在12min内得到基线分离。检测限分别为：水胺硫磷1.2μg/mL和灭多威0.9μg/mL。同时用该方法对通辽地区的大米样品进行了抽检,抽检结果表明：开鲁县大米样品中水胺硫磷和灭多威的残留量最高;科左后旗的大米样品中未检测到水胺硫磷和灭多威这两种农药。     

非水胶束电动毛细管色谱在线富集测定果蔬中克百威和甲萘威残留

建立基于非水胶束电动毛细管色谱在线富集技术测定蔬果中克百威和甲萘威残留的新方法。对影响分离和富集效果的缓冲液参数、分离电压和进样时间进行优化。运行缓冲溶液为含100mmol/L十二烷基硫酸钠、30mmol/L乙酸钠的甲酰胺-乙腈(85:15,V/V)溶液,表观pH值为9.4;分离电压20kV;进样时间150s。在此优化条件下,克百威和甲萘威的富集倍数分别为678和758倍;检出限分别为31μg/L和7.9μg/L;6次重复测定的峰面积相对标准偏差为2.47%、1.76%;平均加标回收率为80.4%～96.2%和92.5%～104.1%。以上结果表明该方法具有良好的灵敏度和重现性,可用于果蔬中该两种农药残留的检测。     

加压毛细管电色谱法分离检测薯片中丙烯酰胺的含量

建立加压毛细管电色谱法检测薯片中丙烯酰胺含量的方法。该方法采用EP-100-20/45-3-C18毛细管色谱柱（总长度45?cm,有效长度20?cm,直径100?μm,ODS填料3?μm）进行分离,并对流动相中有机相比例、磷酸盐缓冲溶液浓度、分离电压等实验条件进行考察和优化。结果表明：在流动相为乙腈-15?mmol/L?NaH2PO4（pH?4.7）缓冲盐溶液（15∶85,V/V）,流动相流速为0.04?mL/min,分离电压为－2?kV,紫外检测波长为202?nm的条件下,薯片中的丙烯酰胺得到了良好地分离。方法在2.0～32?μg/mL范围内线性关系良好,相关系数为0.999?4。丙烯酰胺检出限（RSN=3）为0.30?μg/mL,平均回收率为95.3%～108.1%,相对标准偏差低于1.48%。该方法已经用于薯片中丙烯酰胺含量测定,结果良好。     

固相萃取-毛细管电泳法测定奶粉中三聚氰胺的含量

建立了高效毛细管电泳法测定奶粉中三聚氰胺含量的方法。在背景电解质溶液为30mmol/L的硼砂缓冲液中加入15mmol/L的十二烷基硫酸钠(SDS),运行电压为15kV,压力进样为10s,柱温为25℃,检测波长为200nm。结果表明:三聚氰胺的线性范围20~50μg/mL(r=0.9994),平均回收率为99.3%,检出限为1μg/mL,定量限为2μg/mL。结论是本法简便快捷,结果准确可靠,可作为该成分的质量控制方法。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

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

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status