柱前衍生高效液相色谱法测定5种常见食用菌中的甲醛含量

目的建立柱前衍生-高效液相色谱法测定5种常见食用菌中甲醛含量。方法将干制与新鲜食用菌用超纯水浸泡,浸泡液经2,4-硝基苯肼(DNPH)衍生后,采用高效液相色谱法检测;色谱柱:C18(250mm×4.6mm,5μm),流动相:乙腈-水(70:30, V:V);流速为1.0 mL/min;检测波长352 nm;柱温40℃。外标法定量测定食用菌中甲醛含量。结果柱前衍生法对甲醛浓度在10.70～214.00μg/L范围内与其衍生物峰面积呈良好的线性关系,线性回归系数(r~2)为0.9964,方法的检出限为4.20μg/kg(S/N=3)。加标回收率为78.27%～114.26%,精密度1.55%～9.22%(n=6)。5种食用菌样品仅香菇样品检出甲醛。新鲜香菇甲醛含量超标,干制后香菇甲醛含量降低,低至国家标准含量以下。结论本研究的方法简便、快速、准确、稳定,可用于测定食用菌中甲醛含量。     

柱前衍生-高效液相色谱法测定婴幼儿谷类辅食中的甲醛

目的建立柱前衍生-高效液相色谱法测定婴幼儿谷类辅食中甲醛含量的分析方法。方法样品中的甲醛经柠檬酸钠缓冲溶液和含有2,4-二硝基苯肼的乙腈混合体系衍生提取,生成的甲醛-2,4-二硝基苯腙经色谱柱Agilent Poroshell 120 EC-C18(4.6 mm×150 mm, 2.7μm)以乙腈-水(70:30, V:V)等度洗脱分离,柱温30℃,流速为0.5 mL/min,检测波长为355 nm,外标法定量分析。结果甲醛在0.025～2.00 mg/L质量浓度范围内线性关系良好且相关系数(r2)大于0.995,方法检出限和定量限分别为0.03 mg/kg和0.10 mg/kg,在3个加标水平(1.00、5.00和10.0 mg/kg)的平均加标回收率为86.8%～89.0%,相对标准偏差为0.7%～2.1%。结论该方法操作简便,灵敏度高,重现性好,适用于婴幼儿谷类辅食中甲醛含量的测定。     

柱前衍生高效液相色谱法检测水产品中甲醛的含量

目的建立柱前衍生高效液相色谱法检测水产品中甲醛含量。方法样品经绞碎匀浆后,经2,4-二硝基苯肼-乙酸钠缓冲液衍生液(1:1,V:V)于60℃衍生1 h,冰浴冷却后的衍生物直接上高效液相色谱检测,以ODS-C_(18)柱子为分离柱,甲醇-水(70:30,V:V)为流动相等度洗脱,二极管阵列检测器在365 nm波长处检测,外标法定量。结果甲醛在0~10 mg/L浓度范围内线性关系良好,线性相关系数为0.9994,方法检出限为0.5mg/kg。空白样品在1.0、5.0和20.0 mg/kg添加水平下,回收率在88.2%~95.3%之间,RSD在0.75%~1.82%之间。对水产品9种样品中的甲醛进行了测定,其中6个样品检出甲醛,含量范围为1.51~64.04 mg/kg。结论该方法简便、灵敏、准确,可适用于水产品中甲醛含量的分析。     

乙酰丙酮衍生化高效液相色谱-荧光检测法测定食品中的甲醛

建立基于乙酰丙酮衍生化利用配有荧光检测器高效液相色谱测定食品中甲醛含量的方法。色谱柱为EclipseXDB-C18（250 mm×4.6 mm,5 μm）,流动相为V（乙腈）∶V（水）=20∶80,激发波长为416 nm,发射波长为505 nm,采用外标法定量,甲醛质量浓度在0.001～20.0 mg/L范围内呈良好线性,相关系数为0.999 9。甲醛质量浓度为0.005、0.05、0.5、5.0 mg/L时相对标准偏差分别为4.2%、1.9%、1.4%和0.81%。固体及粉末样品的检出限为0.025 mg/kg,液体样品的检出限为0.025 mg/L。本方法用于干香菇、面粉及啤酒样品中甲醛含量的测定,加标回收率为92.0%～97.7%,相对标准偏差不大于5.6%。结果表明,本方法灵敏度高,方便快捷,结果可靠。     

聚乙烯醇纳米复合膜中残留戊二醛含量的测定

戊二醛作为聚乙烯醇基纳米复合包装材料的交联剂能提高纳米复合材料的综合包装性能,但戊二醛的残留会影响食品包装材料的安全性。对聚乙烯醇纳米复合膜样品采用超声萃取其中残留的戊二醛,并与2,4-二硝基苯肼(DNPH)衍生化后,用高效液相色谱法(HPLC)检测其残留出的戊二醛含量,结果显示:该方法在0.2～5.0mg/L范围内线性相关系数为r2=0.9997,平均回收率达到76.8%～87.3%,相对标准偏差为2.83%～4.08%,最低检测浓度为0.2mg/kg,说明采用的萃取条件及色谱分析方法适合聚乙烯醇基纳米复合膜中戊二醛残留量的测定;待测聚乙烯醇基纳米复合膜中残留戊二醛的含量24.55mg/kg,符合食品包装材料安全限量标准。     

高效液相色谱-荧光法测定皮革中全氟辛酸残留量

建立了柱前衍生-高效液相色谱-荧光检测法(HPLC-FLD)测定皮革中全氟辛酸(PFOA)残留量的方法。以甲醇为萃取剂,室温下超声30min萃取皮革样品中的PFOA,以3-(溴乙酰基)香豆素(3-Br AC)为衍生剂,与PFOA发生衍生化反应,衍生产物通过HPLC-FLD测定,从而检测出PFOA的含量。结果表明:在浓度范围0.5~20mg/L内线性关系良好,最低检出限(LOD)为0.1mg/kg。在优化条件下,皮革样品中PFOA的加标回收率为89.0%~91.5%,相对标准偏差(RSD)为5.48%~6.92%。     

柱前在线衍生-HPLC法测定发芽糙米中γ-氨基丁酸含量

建立柱前在线衍生—高效液相色谱法(HPLC)测定发芽糙米中γ-氨基丁酸(GABA)含量的方法。样品以料液比1:5、超声功率(占总功率)60%、在30℃下超声30 min,提取2次。衍生试剂OPA与样品在线混合10次、衍生2 min,用Agilent Eclipse Plus C18柱分离(流速1 mL/min,检测波长338 nm,柱温40℃)。GABA在5~50 mg/L范围内呈良好线性关系,相关系数大于0.999 0;最低检出限0.33 mg/L,最低定量限1 mg/L,方法添加回收率94.80%~98.40%,RSD为1.82%~2.58%。该方法简单快速、灵敏度高、精确,适合发芽糙米中GABA的检测。     

HPLC法测定市售白酒中的甲醛含量

本研究建立高效液相色谱法测定市售白酒中甲醛含量的分析方法。采用乙腈-2,4-二硝基苯肼和乙酸钠混合体系作为衍生液,在60℃水浴中进行衍生,提取样品中的甲醛。生成的衍生物经色谱柱Inertsil ODS-3-C18(4.6 mm×250 mm,5μm)洗脱,流动相为甲醇∶水(68∶32,V∶V),流速1.0 mL/min,柱温40℃,检测波长为360 nm。结果表明,甲醛在0.0125～1.0 mg/L浓度范围内,线性关系良好,3个不同水平的加标回收率为93.27%～98.06%,RSD值为1.98%,检出限为1.5μg/mL,12种市售白酒中的甲醛含量在0.37～12.98 mg/L之间。该方法操作简单,稳定性好,适用于快速检测白酒中甲醛含量。     

液相色谱-串联质谱法测定黑糖中丙烯酰胺和天冬酰胺

目的建立了一种同时检测食糖产品中丙烯酰胺和天冬酰胺的液相色谱-串联质谱(HPLC-MS/MS)方法。方法食糖产品样品不需要经过衍生,经纯水直接提取净化后就可测定,且方法检出限较低。采用含有5mM/L乙酸铵、0.1%的甲酸水(A)和乙腈(B)作为流动相进行梯度洗脱,质谱采用多反应监测模式(MRM)对定性和定量离子进行监测。结果丙烯酰胺和天冬酰胺在0.1mg/L、0.2 mg/L、0.5 mg/L三个添加浓度上回收率范围为93.5%～108.0%,相对标准偏差1.4%~5.4%;方法检出限为0.005 mg/L~0.01 mg/L。结论本方法前处理操作快速简单,可重复性好,满足国内外对食糖产品中丙烯酰胺和天冬酰胺的快速、准确的检测要求,适合大量样品的准确定量和定性分析。     

高效液相色谱法测定食品中甲醛次硫酸氢钠含量

目的建立高效液相色谱法检测食品中的甲醛次硫酸氢钠含量。方法样品经磷酸溶液提取,残留在其中的甲醛次硫酸氢钠分解释放出甲醛,甲醛与衍生试剂2,4-二硝基苯肼发生反应,生成黄色的衍生物苯腙,经Eclipse XDB-C_(18)(250 mm×4.6 mm,5μm)色谱柱分离,流动相为乙腈-水(60:40,V:V),柱温为35℃,流速为1.0 m L/min;检测波长为355 nm,经高效液相色谱仪检测。结果本方法优化的实验条件是:磷酸溶液浓度2.0%,衍生剂2,4-二硝基苯肼溶液的浓度为2.0%,60℃水浴中反应30 min;甲醛标准溶液在0~3μg/m L浓度范围内具有良好的线性关系(r=1.00);在5、10和30μg 3个加标水平上的回收率为95.36%~98.20%,相对标准偏差为0.403%~1.05%;检出限为0.17 mg/kg。结论本方法快速准确,适合于测定食品中甲醛次硫酸氢钠的残留量。     

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.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.