淀粉-硅酸钠表面施胶剂在瓦楞原纸中的应用

应用淀粉复配硅酸钠水溶液作为表面施胶剂提高瓦楞原纸的环压强度和耐破度。讨论了淀粉-硅酸钠复配体系的黏度及其对瓦楞原纸主要强度指标的影响,并通过Cobb值和接触角表征了施胶后纸张的防水性能。与传统表面施胶剂相比,淀粉-硅酸钠复配体系克服了普通表面施胶剂施胶量低、胶层挺硬性不高的缺陷,使瓦楞原纸的环压强度增幅最高可达80%,耐破度增幅最高可达51%。     

一种新型阳离子复合表面施胶剂的研制及应用

研制了一种新型阳离子复合(AKD-石蜡)表面施胶剂,考察了该施胶剂对瓦楞原纸的施胶效果。结果表明,自制新型阳离子复合表面施胶剂制备工艺简单;相同施胶量下与阳离子SAE施胶剂相比,新型阳离子复合表面施胶剂施胶纸的纵向环压指数、耐破指数和耐折度分别提高14%、8%和25%;当施胶量为2 kg/t纸时,与阳离子SAE施胶剂相比,表面施胶成本降低4元/t纸。     

阳离子苯乙烯/丙烯酸酯共聚物-酶转化淀粉表面施胶剂的研制及应用

使用自制的阳离子聚苯乙烯-丙烯酸酯(HSAE-321)与酶转化淀粉复配成新型表面施胶剂,对瓦楞原纸进行表面施胶.结果表明,新型表面施胶剂不但可以提高瓦楞原纸的抗水性能,还可明显改善其强度性能.当HSAE-321乳液与酶转化淀粉的质量比为1:8,单面施胶量约为3 g/m2时,表面施胶后瓦楞原纸的干、湿环压指数及裂断长与未施胶瓦楞原纸相比分别提高了75%、125%和82%.表而施胶后瓦楞原纸表面的初始接触角增加,并且水珠可在纸面上停留相对较长的时间(约60 s),瓦楞原纸显示出良好的抗水性能.     

硅灰石-淀粉复配体系可用于瓦楞原纸表面施胶

<正>青岛科技大学化工学院陈夫山等人研究了硅灰石-淀粉复配体系在瓦楞原纸表面施胶中的应用。以硅灰石取代一定比例的表面施胶淀粉,对瓦楞原纸进行表面施胶。结果表明,在硅灰石用量10%、表面施胶淀粉用量75%、固定淀粉替代剂用量15%(用量均相对总表面施胶剂质量)的条件下施胶(施胶量6 g/m2),施胶后瓦楞原纸横向环压指数达到5.30 N·m/g,纵向环     

硅灰石-淀粉复配体系应用于瓦楞原纸表面施胶

主要研究硅灰石-淀粉复配体系在瓦楞原纸表面施胶中的应用。以硅灰石取代一定比例的表面施胶淀粉,对瓦楞原纸进行表面施胶。结果表明,在硅灰石10%、表面施胶淀粉75%、固定淀粉替代剂15%(均对总表面施胶剂)的条件下,施胶后(施胶量6 g/m2)瓦楞原纸横向环压指数达到5.30 N·m/g,纵向环压指数达到7.55 N·m/g;横向抗张指数达到46.2 N·m/g,纵向抗张指数达到95.9 N·m/g;横向耐折度达到11次,纵向耐折度达到35次。     

乌洛托品—过硫酸铵改性的淀粉表面施胶剂增强作用研究

通过乌洛托品、过硫酸铵与淀粉反应得到轻度交联-氧化复合变性淀粉,并对其作为施胶剂在瓦楞原纸增强中的应用进行了研究.讨论了乌洛托品用量、过硫酸铵用量、反应pH值和反应时间对瓦楞原纸增强效果的影响,并且对乌洛托品-过硫酸铵改性淀粉表面施胶剂的粘度稳定性进行了研究.结果表明:对瓦楞原纸施胶的最佳条件是,乌洛托品用量1.0%,过硫酸铵用量1.0%,pH=8.0,反应时间15min,在此条件下,环压指数和抗张指数比原淀粉施胶分别增加了26.8%和28.0%.     

淀粉-无机盐体系表面施胶对瓦楞原纸应用性能的影响

主要研究了淀粉-无机盐表面施胶体系对瓦楞原纸应用性能的影响。用硝酸镁、氯化镁、硫酸镁取代部分玉米淀粉对瓦楞原纸进行表面施胶,探讨无机盐的添加对瓦楞原纸物理强度及其他性能的影响。结果表明,当淀粉与无机盐的用量比（质量比）为8∶2、施胶量为6 g/m²时,相对于瓦楞原纸,硝酸镁、氯化镁、硫酸镁替代部分淀粉施胶后纸样的横向环压指数分别增长了76.3%、80.0%、82.5%,纵向环压指数分别增长了74.7%、72.6%、80.9%,耐破指数分别增长了13.1%、14.3%、15.6%。在施胶液中添加接枝淀粉型表面施胶剂,纸张的Cobb值从140 g/m²降至30 g/m²左右,满足成纸的防潮性能要求。     

酚醛树脂作为表面施胶剂的应用研究

研究使用酚醛树脂作为表面施胶剂对瓦楞原纸性能的影响,结果表明,瓦楞原纸经酚醛树脂表面施胶后,环压强度显著提高,耐破度有所下降;氧化淀粉对酚醛树脂有协同增强效应和改善液体吸收效应;酚醛树脂熟化程度越高,越不利于纸张的碎解、疏解.     

壳聚糖改性苯丙聚合物施胶瓦楞原纸的应用与效果

以瓦楞原纸为表面施胶应用研究对象,采用实验室自制固含量为30%的壳聚糖改性苯乙烯-丙烯酸酯聚合物(CSAE)表面施胶剂与氧化的木薯淀粉配制成表面施胶液,在温度60℃条件下对原纸进行表面施胶。结果显示:木薯氧化淀粉溶液浓度为8%、添加木薯淀粉质量比9%的CSAE表面施胶剂制备出的施胶液,对瓦楞原纸施胶后,原纸纵横向环压强度提高24.1%和25.3%、纵横向耐折度提高37.5%和30%、纵横向挺度提高36.8%和38.4%,30sCobb值提高30.1%。研究结果表明,瓦楞原纸在经木薯氧化淀粉/CSAE表面施胶剂协同施胶应用后纸张力学性能提高明显,抗水性显著增强。     

通过表面施胶提高瓦楞原纸的环压强度

对以废纸生产的瓦楞原纸进行表面施胶处理,可以显著提高瓦楞原纸的环压强度.以100%国内OCC为原料,若双面总施胶量为9.0 g/m2,可使112 g/m2瓦楞原纸的环压指数达到8.0 N·m/g以上.     

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.