PVAm/淀粉复合物在再生浆中的应用

通过聚丙烯酰胺（PAM）的霍夫曼反应得到的聚乙烯胺（PVAm）与淀粉共混制备PVAm/淀粉复合物。在中性造纸条件下,PVAm/淀粉复合物对再生浆具有显著的助滤和纸张增强作用。当添加量为0.5%（对绝干浆）时,样品SF-1502的纸张干抗张强度增加33.3%,湿抗张强度提高2倍,打浆度降低41.3%。     

自制纳米纤维素助留/助滤剂及其增强效果

用实验室自制的纳米纤维素为助剂,并与高分子量阳离子聚丙烯酰胺(CPAM)复配组成二元体系,研究其助留、助滤及增强效果。结果表明:自制的纳米纤维素单独使用,对于纸张有较好的增强效果;用自制纳米纤维素与CPAM组成的CPAM/纳米纤维素二元体系具有更加显著的助留/助滤及增强效果,当纳米纤维素、CPAM添加量分别为0.2%、0.15%时,打浆度由44°SR降到28°SR,填料留着率由44%提高到69%,纸张的干抗张强度、撕裂度、耐折度分别提高64%、47%和107%。     

PAMDA-10在硅藻土加填桉木浆中的助滤助留性能

研究了一系列分子量不同的丙烯酰胺与N,N-二甲基二烯丙基氯化铵的链节比为9∶1的共聚物(PAMDA-10)在硅藻土加填桉木纸浆中的助滤助留性能。实验结果表明:PAMDA-10152对桉木浆0.3%添加时,可使该浆料的打浆度从44.0°SR下降到29.0°SR,白水浊度从9.52NTU降低到4.90NTU;PAMDA-10152对硅藻土加填纸浆0.5%添加时,可使该浆料的打浆度从57.5°SR降低到36.5°SR,白水浊度从56.70NTU降低到14.02NTU,硅藻土的留着率达到97.31%。     

阳离子聚丙烯酰胺基复合物助留助滤及其作用机理

将羟丙基壳聚糖(HPCS)、CPAM及PAE树脂通过交联制得HPCS-CPAM-PAE复合物,探讨其对废旧瓦楞纸浆的助留助滤效果,并与CPAM及HPCS/CPAM/PAE混合物的效果进行比较。结果表明:HPCS-CPAM-PAE复合物具有良好的助留助滤作用效果,当用量为0.5%(质量百分比,对绝干纸浆)时,浆料的单程留着率达到95%,滤水量达到最大值;并且其助留助滤效果优于CPAM和HPCS/CPAM/PAE混合物。并对该复合物的助留助滤作用机理进行了初步探讨。     

JOS/PD复合物的相对分子质量与助留助滤性能

采用多角度激光光散射仪(MALIs)-体积排除色谱法(SEC)联用技术研究了交联氧化淀粉(JOS)与聚二甲基二烯丙基氯化铵(PD)形成的复合物(JOS/PD)的质均相对分子质量(Mw)及分布,探讨了JOS的羧基含量对复合物肘Mw的影响,考察了复合物对废纸浆的助留助滤性能.结果表明,芭蕉芋交联淀粉(JS)的Mw主要分布在1.1×106～2.0×107,其均方旋转半径为236 nm,约是原淀粉(76 nm)的3倍.NaClO氧化导致JOS的羧基含量增大,Mw大幅减小.JOS的氧化程度越大,JOS与PD的复合作用越大,JOS-6的Mw为9.2×104,而JOS-6/PD的Mw为1.0×106.JOS/PD的阳离子含量随JOS羧基含量的增大而减小.JOS/PD用于废纸浆时显示出优良的助留助滤作用,当w(JOS-2/PD)=0.5%时,废纸浆的打浆度和滤液的浊度分别减小63%和81%.JOS/PD的分子形态和离子含量影响其助留助滤件能.     

纳米TiO2胶体多元复配体系对DIP的助留助滤研究

利用动态滤水实验,通过检测留着率和滤水时间来考察纳米TiO2胶体多元复配体系对脱墨浆(DIP)抄造新闻纸过程的助留助滤作用.结果表明,二元体系中,AmS(两性淀粉)-TiO2二元复配体系助留助滤效果最好,当纳米TiO2胶体用量0.20％和AmS用量0.5％时,其滤水时间是13s,其总留着率达到93.4％;在三元体系中,当CS(阳离子淀粉)用量0.4％、APAM(阴离子聚丙烯酰胺)用量0.01％和纳米TiO2胶体用量0.2％时的体系的滤水时间最小,为17s;当CS用量0.4％、CPAM(阳离子聚丙烯酰胺)用量0.01％和纳米TiO2胶体用量0.2％时总留着率最大,为97.5％.研究发现,纳米TiO2胶体多元体系具有好的助留助滤效果,淀粉系列因为具有三维结构,为纤维、DCS(溶解和胶体物质)的絮聚提供了更多的结合机会,而PAM(聚丙烯酰胺)系列主要通过桥联、电荷吸附以及补丁絮聚机理实现好的助留助滤效果.     

聚乙烯胺在CaCO3加填造纸中的助滤助留效果

本研究主要探讨了在弱碱性条件下聚乙烯胺(PVAm)对CaCO3加填的马尾松机械磨木浆(机械浆)和漂白芦苇化学浆(芦苇浆)的助滤、助留效果。实验结果表明，PVAm在两种浆中都有非常显著的助滤、助留效果，且在芦苇浆中的作用效果大于机械浆中的。低电荷密度PVAm在两种浆中的助滤、助留效果比高电荷密度PVAm的大。     

改性淀粉-TiO2体系对含不同填料的脱墨浆助留助滤效果研究

改性淀粉-TiO2体系作为助留助滤剂通过与含不同填料的脱墨浆作用,考察对浆料和填料的助留助滤效果。实验结果表明,改性淀粉-TiO2体系对浆料的留着以滑石粉为填料时最好,当两性淀粉(AmS)用量为0.4%、纳米TiO2用量为0.2%时,滑石粉为填料时总留着率达到91.8%,滑石粉留着率为94.3%;高岭土为填料时总留着率为87.8%,高岭土留着率为90.3%;钛白粉为填料时总留着率为87.3%,钛白粉留着率为91.1%;碳酸钙为填料时总留着率为81.4%,碳酸钙留着率为69.5%;滤水时间则是碳酸钙为填料时最少,为20 s,其次分别是滑石粉33 s、钛白粉48 s、高岭土53 s。     

聚乙烯胺在草浆造纸中的应用

研究了由聚N-乙烯基甲酰胺的碱性水解得到的聚乙烯胺在芦苇浆和麦草浆造纸中对纸张的增强、助滤和助留作用.实验结果表明:浆中添加w=0.2%的聚乙烯胺,可使芦苇浆和麦草浆纸张的干抗张强度分别提高23.3%和12.7%,湿抗张强度分别为干抗张强度的12.1%和11.2%;打浆度分别从30°SR降至12°SR和18°SR;纤维留着率分别从60.0%提高到80.5%和从79.5%提高到85.0%.     

高取代度阳离子淀粉对废纸脱墨浆助留助滤的研究

将半干法制备的高取代度阳离子淀粉应用于废纸脱墨浆作助留助滤剂.研究表明,高取代度阳离子淀粉带有更多的正电荷,能更好地作用于纤维,对废纸脱墨浆有显著的助留助滤作用;当取代度为0.509的高取代度阳离子淀粉加入量为0.08%时,打浆度下降11.5°SR,填料留着率达79.8%.     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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