皮革废弃物中提取胶原蛋白合成表面施胶剂

利用苯乙烯和丙烯酸丁酯对从皮革废弃物中提取的胶原蛋白进行改性,得到一种改性胶原蛋白乳液,并将该乳液单独应用于瓦楞原纸的表面施胶。通过考察施胶后纸张的力学性能和抗水性,确定合成的最佳工艺。实验结果表明:当胶原蛋白与单体的质量比为1∶1.5,引发剂的用量为单体的3.5%,单体中苯乙烯和丙烯酸丁酯的比例为1∶1,反应时间为2h,此时纸张的力学性能和抗水性最好。将合成的改性胶原蛋白乳液与其他胶液复配,并考察施胶效果。     

空气滤清器滤纸新型浸渍乳液的研究

采用半连续乳液聚合的方法.以亚硫酸氧钠-过硫酸钾为引发剂.十二烷基硫酸钠(SDS)为乳化剂,合成了一种以氧化淀粉(OS)、苯乙烯(ST)和丙烯酸丁酯(BA)为主要原料的空气滤清器滤纸浸渍乳液.考察了乳化剂、引发剂、氧化淀粉用量及单体配比对乳液性能的影响.将其用于滤纸浸渍实验,发现可显著提高滤纸的物理强度、挺度和防水性能.     

乳液型发动机滤纸浸渍剂的合成及其性能

采用种子乳液聚合的方法合成了平均粒径在120nm左右的丙烯腈（AN）／苯乙烯（ST）／丙烯酸丁酯（BA）共聚物乳液，研究了动力学参数对聚合的影响，确定了最佳合成工艺条件，考察了单体配比、乳化剂用量以及交联剂用量对共聚物的耐水耐油性能的影响，将合成的共聚物乳液用于发动机滤纸浸渍试验，发现经丙烯腈和交联单体改性的共聚物乳液可显著提高滤纸的物理强度、挺度和防水性能。     

阴离子自交联苯丙乳液的成膜抗水性能研究

以苯乙烯(St)、甲基丙烯酸甲酯(MMA)为硬性单体,丙烯酸丁酯(BA)为软性单体,N-羟基甲基丙烯酸酰胺(N-MA)为自交联单体,以丙烯酸(AA)、α-甲基丙烯酸(MAA)作为功能单体,采用预乳化种子乳液聚合法合成了稳定的自交联苯丙乳液。考察了苯乙烯用量、乳化剂用量、自交联单体用量及功能单体用量对乳液涂膜吸水率的影响,结果发现,稳定自交联苯丙乳液的适宜合成条件为软硬单体质量比mBA∶(mSt+mMMA)为0.9～1.1,St用量在25%～27%,乳化剂用量为1.5%～2.5%,阴离子和非离子乳化剂配比为1∶1,N-MA用量为2.5%,AA和MAA用量均为0.5%,此条件下合成乳液的转化率达到95%以上,涂膜抗水性好,膜平滑、透明且无气泡,可见该自交联苯丙乳液有着较优异的稳定性、成膜性和涂膜抗水性。     

滤清器滤纸浸渍用苯丙乳液耐水性的研究

采用乳液聚合方法制备出以苯乙烯、丙烯酸丁酯(BA)为主体,加入其他功能性单体共聚的苯丙乳液.探讨了共聚单体组成、乳化剂以及交联剂对乳液成膜和经乳液浸渍滤纸的耐水性和物理机械性能的影响.结果表明,加入疏水性的共聚单体或乳化剂均可以有效地提高乳液成膜和经乳液浸渍滤纸的耐水性、强度和挺度.此外,交联剂浓度的增加也可以使胶乳成膜后的耐水性及经乳液浸渍滤纸的耐水性、强度及挺度有所提高.     

苯丙乳液对汽车工业滤纸性能的影响

采用苯乙烯(ST)、丙烯酸丁酯(BA)、丙烯酸(AA)和N-羟甲基丙烯酰胺(N-MA)合成出共聚苯丙乳液;用其浸渍原纸,交联固化后得到汽车工业滤纸,并研究了自制苯丙乳液的ST/BA质量比,丙烯酸、N-羟甲基丙烯酰胺、乳化剂的用量与配比和引发剂用量等参数对滤纸各项性能指标的影响。     

不同复配乳化剂合成乳液对汽车工业滤纸强度性能的影响

以苯乙烯和丙烯酸酯为主要单体,设计多种复配乳化剂方案,通过单体预乳化、半连续乳液聚合法合成苯丙乳液,用作汽车发动机空气滤清器滤纸浸渍树脂.研究了多种复配乳化剂合成苯丙乳液浸渍对汽车工业滤纸抗张强度、耐破度及挺度的影响,筛选出对滤纸强度性能作用效果良好的复配乳化剂.结果表明,合成乳液浸渍对提高汽车工业滤纸抗张强度、挺度及耐破度作用显著,OP-10/FR-1、OR-2/DSB、FOR-3/RE-610复配乳化剂乳液浸渍的汽车工业滤纸抗张强度高于3.15kN/m、挺度大于3.45 mN·m、耐破度在250 kPa以上.     

低温环保型聚丙烯酸酯乳液的合成及应用

采用种子乳液聚合法合成低温环保型聚丙烯酸酯乳液粘合剂,即以丙烯酸丁酯(BA)、丙烯酸异辛酯(EHA)、苯乙烯(ST)为软、硬单体,丙烯酸(AA)为功能单体,过硫酸钾为引发剂,HA为交联单体,合成了一种性能优良的聚丙烯酸酯涂料印花粘合剂。讨论了软硬单体配比、功能单体用量、交联单体用量及链转移剂对乳液性能及涂料印花性能的影响。最终确定了乳液聚合最佳工艺条件:软/硬单体比为1.2188/1,功能单体AA用量为1.8%,交联单体HA用量为2.6%,链转移剂硫醇用量为0.52%。合成粘合剂在涂料印花上应用时,粘合剂用量为30%,焙烘时间为4min。     

核壳型含氟防水透湿整理剂的合成及其性能

以甲基丙烯酸六氟丁酯(FA-02)、甲基丙烯酸甲酯(MMA)及丙烯酸丁酯(BA)为原料,采用核壳乳液聚合法,合成了核壳型含氟防水透湿整理剂乳液。当壳层单体FA-02与BA质量比为3.5∶1、核壳乳化剂FS-200与LAS的体积比为1∶1、壳层预乳化液滴加时间为90 min、乳化剂用量为1.8%、单体转化率达到90%、交联单体甲基丙烯酸羟乙酯(HEMA)用量为2%时,可以合成外观透亮、细腻、性能稳定的乳液。在最佳防水透湿整理工艺下,核壳型含氟防水透湿整理剂整理后的棉织物对水的接触角可以达到129.3°,透湿量为2 319.3 g/m2·24 h。     

硅溶胶/淀粉阳离子苯丙乳液表面施胶剂的合成及应用

实验以氧化淀粉为高分子分散剂,利用正硅酸乙酯水解生成硅溶胶与丙烯酸酯、苯乙烯、丙烯酸十八酯、阳离子单体DMC、乙烯基硅氧烷偶联剂进行无皂乳液聚合,制备硅溶胶/淀粉阳离子苯丙乳液表面施胶剂,研究了阳离子单体DMC、正硅酸乙酯、甲基丙烯酰氧丙基三甲氧基硅烷(KH570)的用量对硅溶胶/淀粉阳离子苯丙乳液表面施胶剂作用效果的影响。研究发现最佳的反应条件为淀粉:单体=1∶2,阳离子单体10%,苯乙烯∶丙烯酸丁酯为1.3∶1、丙烯酸十八酯为3%、正硅酸乙酯为2%,甲基丙烯酰氧丙基三甲氧基硅烷(KH570)为2%,FeSO4/H2O2为0.03。     

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.