8-羟基喹啉荧光分光光度法测定油炸食品中铝

目的改进8-羟基喹啉荧光分光光度法并用于油炸食品中铝含量测定。方法采用湿法消解对食品进行前处理,使铝元素与8-羟基喹啉形成稳定荧光络合物,用荧光光度计检测其荧光强度从而测定铝含量。结果铝离子在5～600μg/L浓度范围内与荧光强度呈线性关系,相关系数R2=0.997 1;回收率在90.1%～106.0%之间。结论该方法操作简便快捷,测定结果准确,灵敏度高,非常适合于基层的工商、卫生和质检部门在日常工作中分析油炸食品中铝的含量。     

紫外分光光度法测定粉条中铝含量的 两种前处理方法比较

目的比较干法灰化和湿法消解2种前处理方法对粉条中铝残留量测定的影响。方法分别用干法灰化和湿法消解两种方法处理样品,采用国标方法显色后用紫外分光光度法测定加标样品及质控样中铝的含量,比较回收率和重复性。结果干法灰化法回收率和重复性都明显高于湿法消解法。干法灰化法的回收率为99.3%～110.5%,平均回收率为104.3%;湿法消解法的回收率为70.2%～83.0%,平均回收率为77.6%;干法灰化法的重复性RSD为9.3%,湿法消解法的RSD为14.9%。结论干法灰化法的前处理方法简单、快捷、可操作性强,对环境和实验者的危害更小,更适合应用于粉条的批量检验。     

食品中铝含量检测优化技术体系研究

目的建立高效的测定食品中总铝和可溶性铝的测定方法。方法采用微波消解法(HNO_3、HNO_3+H_2SO_4、HNO_3+HF)与湿法消解法(HNO_3、HNO_3+H_2SO_4)进行样品前处理,在铬天青S分光光度法和电感耦合等离子体发射光谱法(inductively coupled plasma optical emission spectrometry,ICP-OES)下测定标准参考物质与普通样品铝含量,同时用添加回收实验验证方法的可靠性与准确性。结果采用微波消解法(HNO_3+HF)-优化铬天青S分光光度法和微波消解法(HNO_3+HF)-ICP-OES时,标准参考物质的铝含量测定结果在标准参考值范围内,这2种方法的加标回收率为86.5%~101.1%;采用微波消解(HNO_3)-ICP-OES法、微波消解(HNO_3)-铬天青S分光光度法与湿法消解(HNO_3+H_2SO_4)-铬天青S分光光度法时,测得普通样品的标准偏差为0.50~4.22 mg/kg,加标回收率为74.3%~99.0%。结论微波消解法(HNO_3+HF)-优化铬天青S分光光度法和微波消解法(HNO_3+HF)-ICP-OES法,均可准确测得总铝含量;微波消解(HNO_3)-ICP-OES法、微波消解(HNO_3)-铬天青S分光光度法与湿法消解(HNO_3+H_2SO_4)-铬天青S分光光度法测得的结果是可溶性铝。     

微波/湿法/干法消解——分光光度法测定馒头中的铝含量

采用微波消解、湿法消解和干法消解对馒头进行样品前处理,用分光光度法测定自制馒头中的铝含量,建立了微波/湿法/干法消解-分光光度法测定铝的方法.实验结果表明,湿法消解测定的结果不稳定,相对误差较大,超出了要求范围;微波消解和干法消解,相对误差较小,且均在要求范围内,但是,微波消解法所用仪器设备昂贵,一般实验室无法实现,而干法消解所需设备简单、操作简便、试剂用量少、检测结果准确度高、精密度好.因此,干法消解法为最优的前处理方法.     

微波消解-分光光度法测定膨化食品中铝的含量

目的 建立微波消解-分光光度法测定膨化食品中铝的方法。方法 采用微波消解法代替酸消解法处理样品, 在GB 5009.182-2017《食品安全国家标准 食品中铝的测定》方法的基础上对检验条件(络合物显色稳定性、溶液pH、反应时间等)进行优化。结果 在优化条件下, 铝在0~5 μg范围内线性良好(r=0.9997), 样品加标回收为91.0%~99.0%, 相对标准偏差为0.46%~1.09%。结论 与国标法中湿法消解法相比, 微波消解法显色更稳定、消解试剂用量更少、过程更环保, 且前处理液可用于其他金属元素联测, 对实现低碳绿色分析具有现实意义。     

分光光度法和等离子体发射光谱法测定茶叶中铝

在国标中对茶叶中的铝是运用分光光度法进行测定,但是这种方法存在诸多缺点,如前处理复杂,并且处理后的样品不稳定。研究等离子体发射光谱法(Inductively coupled plasma atomic emission spectrometry,ICP-AES)测定茶叶中铝的含量。结果表明:等离子体发射光谱法具有简单、高效的特点。等离子体发射光谱法与分光光度法对铝测定结果基本一致。等离子体发射光谱法可以替代分光光度法测定茶叶中铝。     

微波消解-铝试剂分光光度法测定面制食品中铝的含量

正铝是一种低毒元素,当人体中摄入过多量时,会对人的神经系统、骨骼、造血系统等造成不良影响。目前,含铝的食品添加剂广泛应用于面制食品的加工过程中,当前测定面制食品中的含量有原子吸收光谱法、电感耦合等离子体原子发射光谱法、分光光度法等,但存在需要大型仪器支持、操作复杂或操作简便但灵敏度较低等问题。本文采用微波消解法对面制品进行前处理,以铝试剂为显色剂,研究铝试剂分光光度法测定食品中铝的含量,建立微波消-分光光度法测定铝的方法,样品     

焙烤和面制食品中铝残留量的测定及监管建议

目的抽样调查嘉兴地区生产的焙烤和面制食品中铝残留量。方法按GB/T 5009.182-2003《面制食品中铝的测定》方法标准,样品前处理采用微波消解、干法或湿法消解,终产品中铝残留量用分光光度计测定。结果按照国家食药总局规定要求,对其铝残留量检测和判定,合格率为95.1%。结论嘉兴地区焙烤和面制食品中使用含铝添加剂的总体情况较好,少数产品使用量超标。     

微波提取分光光度法快速测定食品中含铝添加剂

建立微波提取分光光度法测定食品中含铝添加剂的方法。将样品粉碎、微波提取后分光光度法定量,并对提取条件进行优化、方法进行验证。该方法将前处理时间从传统的数小时缩短为1 min,平均回收率为90.6%~97.2%%,平均相对标准偏差2.1%~4.7%、t检验值为0.35,P0.05。方法的建立弥补了快速测定食品中含铝添加剂方法的空白,且稳定、可靠,可应用于快速筛查、现场监测以及实验室中。     

磷钼蓝分光光度法测定磷系阻燃聚酯切片中磷含量

介绍了分光光度法测定磷系阻燃聚酯切片中磷含量的方法。通过对消解试剂、最大吸收波长、最佳酸度、显色时间和络合物稳定性等条件参数进行优化,提出采用硫酸-过氧化氢湿法消解磷系阻燃聚酯切片的肖解体系,使用磷钼蓝分光光度法测定其磷含量。结果表明:在最优化条件下,磷元素在0.10～1.00μg/mL范围内呈线性关系,相关系数为R~2=1,加标回收率为94.0%～106.0%,测定结果的相对标准偏差为0.7%～2.9%。该法操作简单、快速、准确。     

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.     

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.     

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.     

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.