TiO2-沸石复合纸板制备中助留剂的作用

考察了TiO2-沸石复合纸板制备中聚二甲基二烯丙基氯化铵(PDADMAC)/阴离子聚丙烯酰胺(APAM)和阳离子淀粉/APAM二元助留体系助留效果。结果表明:PDADMAC/APAM二元助留体系对TiO2、沸石等无机物的助留效果显著,纸料和无机物的最高留着率分别达88.8%和83.0%。PDADMAC或APAM单元体系、阳离子淀粉/APAM二元助留体系的作用效果差。     

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.     

杨木P-RC APMP中溶解和胶体物质对湿部化学的影响

研究了溶解和胶体物质（DCS）对造纸湿部化学的影响。结果表明,DCS的加入能够降低单元助留助滤体系阳离子聚丙烯酰胺（CPAM）、双元助留助滤体系聚二甲基二烯丙基氯化铵（PDADMAC）/CPAM和微粒助留助滤体系CPAM/膨润土的助留助滤效果,并且能够使得不同助留助滤体系存在下的杨木P-RC APMP的Zeta电位下降。DCS的加入降低了阳离子助剂对滑石粉的絮聚程度,但随着DCS加入量的增加,阳离子助剂对碳酸钙的絮聚程度先下降后增加。同时,DCS的加入使得不同施胶剂的施胶效果变差。PDADMAC作为施胶促进剂对不同施胶剂或者含有不同DCS的浆料有一个最佳用量。     

季铵型两性PAM对麦草浆的助留助滤作用

用水溶液共聚法合成了一系列季铵型两性聚丙烯酰胺（LPAM）。分别考察了阳离子化度和用量对麦草浆滤水性、填料留着率和动态条件下一次留着率的影响，发现季铵型两性PAM可显著提高漂白麦草浆的滤水性和填料留着率，两性PAM与PAC、PDADMAC和膨润土配合使用可进一步改善漂白麦草浆的留着和滤水。     

CPAM/改性膨润土微粒助留助滤体系的应用研究

采用碳酸钠改性的膨润七与阳离子聚丙烯酰胺(CPAM)组成的微粒助留助滤体系在纸板生产中进行行试试验,结果表明,微粒助留助滤体系可以显著改善纸板的匀度、加强纸板芯层浆的脱水、有效提高细小纤维的留着率.当CPAM与改性膨润上用量分别为0.25 kg/t浆与2 kg/t浆时,与单元助留相比,纸板平滑度提高5.6%,留着率提高7.5%,出网部干度提高4.9%,纸板挺度提高4.4%.     

纳米TiO2—两性淀粉对脱墨浆新闻纸抄造过程中DCS去除的研究

研究了两性淀粉（AmS）、纳米TiO2单元体系、纳米TiO2-AmS双元体系、阳离子淀粉（CS）／阳离子聚丙烯酰胺（CPAM）／阴离子聚丙烯酰胺（APAM）三元体系对全脱墨浆（DIP）的动态絮聚作用,并考察这几种助留助滤体系在白水循环使用情况下,对抄造纸页部分性能及白水中DCS去除效果的影响。动态絮聚实验表明：AmS单元体系几乎没有去除DCS的作用,增大用量还会使体系的DCS残留量更高;纳米TiO2单元体系有一定的DCS去除效果;TiO2-AmS双元体系不仅提高了DCS的去除效果,还降低试剂用量,当其用量为0．16％（TiO2）-0．4％（AmS）时,DCS的去除率达到50％以上;三元体系的助留助滤效果较好,但是DCS的去除效果一般。白水循环使用抄纸实验表明：纳米TiO2-AmS体系对残余油墨的捕集能力最强,对DCS的去除效果也最好,在白水循环抄纸进行到22次时,DCS的富集量达到平衡,白水离心处理后CODCr值为43mg／L左右,较好抑制了DCS的进一步富集;三元体系在循环进行到52次时,其离心处理后白水CODCr值稳定在65mg／L左右。     

有机改性膨润土微粒助留助滤剂的制备及其性能研究

采用反相微乳液聚合法,以丙烯酸和丙烯酰胺为单体,合成阴离子有机微粒,并用其改性蒙脱石含量低的钙基膨润土,制备改性有机复合膨润土,分析改性后膨润土的形貌、层间距、粒径、荷质比等变化,研究改性膨润土在造纸湿部中的助留助滤性能。结果表明:经阴离子有机微粒改性后,有机复合膨润土的片层遭到破坏,粒径及层间距减小;在有机微粒加入量1%时(相对于膨润土的量),有机微粒复合改性膨润土的粒径达到最小值2.60μm,荷质比为-1.01×10-4mol/g。在此粒径和荷质比下,有机微粒复合改性膨润土与CPAM助留助率体系对纸料中细小组分的助留助滤效果最好。     

不同助留体系对装饰原纸二氧化钛复合填料留着效果的影响

本研究分别分析了单元助留体系阳离子聚酰胺环氧氯丙烷树脂（PAE）,双元助留体系PAE/阴离子聚丙烯酰胺（APAM）、PAE/膨润土（MMT）、PAE/阳离子聚丙烯酰胺（CPAM）,三元助留体系PAE/CPAM/APAM、PAE/CPAM/MMT对装饰原纸TiO₂/滑石粉复合填料留着效果的影响。确定了各个体系的最佳添加量,并筛选出助留效果最好的助留体系。结果表明,当PAE添加量2.0%、CPAM添加量0.08%、MMT添加量0.6%时,组成的PAE/CPAM/MMT三元助留体系留着效果最佳,此时,浆料和填料留着率分别为89.5%和65.0%,纸张的不透明度、白度及匀度分别为98.5%、86.6%和91。     

新型两性聚丙烯酰胺对二次纤维的助留助滤性能

采用反相微乳液聚合制备了新型的两性聚丙烯酰胺助留助滤剂，通过检测两性聚丙烯酰胺对二次纤维的助留助滤性能优化聚合工艺，得到最佳聚合条件为：EDTA加入量0．5％（对单体质量）；搅拌速度为300r／min；乳化剂用量为18．61％（对乳液总质量）；反应时间为3h；引发剂用量为0．5％；单体质量分数为50％（对水相质量）；反应温度为25℃。检测了优化后制备的两性聚丙烯酰胺的助留助滤性能，结果表明，该两性聚丙烯酰胺具有较好的助留助滤性能，当加入量为0．08％（对绝干浆）时，纸料留着率提高了8．9％，打浆度降低了6．1°SR。     

不同CPAM体系对高得率浆助留助滤性能的影响

考察了自制W／O型和w／w型阳离子聚丙烯酰胺（cPAM）／膨润土体系对高得率浆滤水和留着性能的影响。同时,探讨了高阳电荷密度聚合物改性聚乙烯亚胺（PEI）作为阴离子垃圾捕捉剂,对高得率浆CPAM／膨润土体系助留助滤性能的影响。结果表明,具有较高电荷密度的W／O型CPAM单元体系对高得率浆的助留助滤效果较好;但其与膨润土组成的微粒体系与单元体系相比,进一步提高纸料滤水和留着效果不明显。PEI可以显著改善CPAM或CPAM／膨润土体系对高得率浆的助留助滤性能。PEI与W／O型CPAM（／膨润土）组成的体系对纸料的助留助滤效果较好。当PEI用量为0．02％和CPAM用量为0．03％时,PEI／W／O型CPAM使纸料的滤水速度和总留着率比PEI／W／W型CPAM分别提高了9．5％和1．9％。     

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.     

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.     

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