离子色谱法测定燕窝中亚硝酸盐的含量

建立用离子色谱法测定燕窝中亚硝酸盐含量的方法,并检测市售干燕窝中亚硝酸盐的含量。样品经前处理后,用IonpacAS23分离柱,4.5mM Na2CO3/0.8mM NaHCO3作淋洗液,1mL/min的流速分析,通过抑制电导检测器进行测定。结果表明:该法的最低检出限为亚硝酸盐(以NaNO2计)1.407mg/kg,相关系数为0.999 8,精密度为1.301%。干燕窝直接检测的亚硝酸盐的残留量为4 353mg/kg,浸泡清洗后的燕窝亚硝酸盐的残留量为114.7mg/kg,磨碎的燕窝浸泡清洗后亚硝酸盐的残留量为102.2mg/kg。该法简单,快捷,可靠,适合于大批量干燕窝样品中亚硝酸盐的测定。     

鸡爪中过氧化氢残留量的影响因素研究和检测方法比较

目的模拟凤爪生产过程,研究不同因素对鸡爪中过氧化氢残留量的影响和不同检测方法结果的比较。方法本文用过氧化氢溶液浸泡鸡爪,控制浸泡液浓度和浸泡时间,采用GB 5009.226-2016中钛盐比色法和碘量法测定鸡爪中过氧化氢的残留量。同时进行加标回收和实际样品检测实验。结果当浸泡液浓度达到1.0×103mg/kg及以上时,只需浸泡20 min即在鸡爪中检出较高过氧化氢残留量。鸡爪中过氧化氢残留量随浸泡液浓度和浸泡时间的增加而增加。碘量法和钛盐比色法的检测结果相一致。回收率为86.0%～91.2%,相对标准偏差均小于3.41%(n=6)。结论 2种方法均能有效检测鸡爪中残留过氧化氢。     

离子色谱法检测干笋中的二氧化硫

建立一种简单快捷的离子色谱法测定干笋中二氧化硫残留的方法。样品经浸泡后蒸馏,利用1.5%的H2O2溶液将二氧化硫氧化为硫酸根,通过离子色谱法测定。结果表明:二氧化硫含量在2.0μg/mL~32.0μg/mL范围内线性良好,相关系数r2为0.999,检出限为0.1 mg/kg,定量限为0.3 mg/kg,加标回收率达到83.6%~90.4%。     

广州市场部分蜜饯中SO_2残留量调查

采用国标GB／T5009．34——2003第2种方法（蒸馏法）对广州市场上7类共43个蜜饯产品中的SO2残留量进行分析测定,同时测定样品中的糖度、总酸度和水分含量等指标。结果显示,SO2残留量超过国家GB2760——2007《食品添加剂使用卫生标准》规定标准（0．35g／kg）的有10个产品,占调查总数的23．26％,残留量为0．4704—3．8411g／kg;残留量超标严重的两个波萝果脯产品分别超出规定标准的9．08倍和10．97倍;合格产品的SO2残留量为0．0005～0．2530g／kg。调查结果表明,同类产品不同厂家之间的SO2残留量差异较大。     

食品中甲醛残留量高通量检测方法研究

建立食品中甲醛残留量的高通量快速检测方法。样品中的甲醛在酸性条件下与2,4-二硝基苯肼发生加成反应,经高效液相色谱紫外检测器检测,流动相乙腈∶水(6∶4,体积比),流速1.0 m L/min,检测波长355 nm。该方法在0.05μg/m L~5.0μg/m L质量浓度范围内线性关系良好(R2=0.999 9),检出限为0.5 mg/kg,加标回收率为80.2%~107.7%。该方法操作简便、快速、实用性广,可为面粉、粉条、虾皮、竹笋、腐竹、鱼类(鱿鱼、鲫鱼等)、血豆腐等多种食品基质中甲醛残留量的检测提供参考。     

真空冷冻干燥绿芦笋的护绿方法研究

研究真空冷冻干燥绿芦笋的最佳护绿技术,采用分光光度法测定总叶绿素含量,以总叶绿素保存率为定量指标进行比较。结果表明:绿芦笋在0.8%Na2CO3碱液中按料液质量比1∶1.2浸泡10min,取出后,经温度100℃的0.04%ZnCl2+0.1%CaCl2+0.01%Na2SO3复合护绿液,按料液质量比1∶10烫漂100s,在板温90℃、真空值20～25Pa、物料最高温度55℃的条件下,其总叶绿素保存率可达86%,冻干品终水分在4.0%以下;同时,经检测复水冻干品中的Zn和SO2残留量分别为19.5mg/kg及0.028g/kg,符合产品质量卫生要求。本技术对绿芦笋冻干品有较佳的护绿效果。     

基于电子鼻分析包装材料对即食水竹笋冷藏品质的影响

为提高真空冷冻干燥即食水竹笋的品质,采用真空包装袋、高温蒸煮袋、复合铝箔袋对即食水竹笋进行包装,4℃贮藏30 d,研究其水分含量、水分活度、脂肪含量、过氧化值4个指标的变化,并结合电子鼻分析挥发性物质的变化规律。结果表明:随着贮藏期的延长,3种包装的即食水竹笋的水分含量、水分活度、过氧化值逐渐升高,脂肪含量逐渐下降;电子鼻检测结果显示,氮氧化合物、萜烯类、含硫化物和芳香族化合物是即食水竹笋主要的挥发性成分,其释放量随着贮藏期的延长逐渐提高。贮藏30 d,与真空包装袋、高温蒸煮袋相比,复合铝箔袋包装即食水竹笋的水分含量最低,为2.8 g/100 g,水分活度增加最小,为0.04,脂肪损失最少,为2.6%,过氧化值增加最少,为5.2 g/100 g,挥发性物质变化最小。经综合评定,在4℃条件下,复合铝箔袋包装能够更好地保持即食水竹笋产品的品质。     

毛竹笋酒发酵工艺研究

以毛竹笋加工后的剩余笋头以及鲜叶为原料,通过单因素、正交试验确定笋酒的最佳生产工艺。结果表明,毛竹笋头和毛竹鲜叶(9∶1)中加入2倍质量的水,加糖量为22%,0.3‰的安琪葡萄酒高活性干酵母,80 U/g糖化酶,60 U/g纤维素酶,30℃发酵3 d,得到酒精度13.5%vol、残总糖24.68 g/L、总酸0.62 g/L的毛竹发酵笋酒。     

微量滴定法测定魔芋精粉中SO2的研究

本文提出以常量蒸馏微量滴定法，测定魔芋精粉中SO2残留量，并同蒸馏氧化法(GB/T 5009．34-1996)进行对比。对同一种样品，两种方法的测定结果分别为：2．055g／kg、2．051g／kg：变异系数分别为：0．16％、0．18％，两种方法无显著性差异。常量蒸馏微量滴定法，样品试剂用量少，缩短了分析时间，降低了成本，是一种测定魔芋精粉中SO2残留量很合适的分析方法。     

液相色谱法测定肉制品中万古霉素的残留量

采用液相色谱法测定肉制品中万古霉素的残留量。样品经过0.1%甲酸水-乙腈(体积比为7∶3)提取,二氯甲烷去脂,固相萃取柱净化,利用液相色谱仪,采用外标法定量检测。结果显示,万古霉素液相色谱检测方法的线性范围是8.5μg/mL^170μg/mL,线性相关系数大于0.99。方法检出限为0.5 mg/kg,定量限为8 mg/kg。添加回收率在75%~95%,精密度为5%~8%。该方法适用于肉制品中万古霉素残留量的测定。     

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