木薯阳离子淀粉的合成及其对脱墨浆增强和助留的效果

介绍合成木薯阳离子淀粉的影响因素,确定出合成阳离子淀粉的最佳工艺条件,表明木薯阳离子淀粉合成最佳条件是:阳离子醚化剂是淀粉用量的5%,反应温度50℃,反应时间6h;对取代度为0.03的木薯阳离子淀粉在脱墨浆中当用量为绝干浆料的0.8%时,浆料留着率和成纸强度的效果都是最好的。     

层间加填中黏合剂的特性及复配比例对成纸性能的影响

以废纸抄造瓦楞原纸,选用重质碳酸钙为填料,苯丙乳液与两种取代度不同的阳离子淀粉为黏合剂,考察了黏合剂的种类、用量以及不同黏合剂的复配比例对成纸物理强度性能的影响。结果表明:采用苯丙乳液作为黏合剂的效果优于两种取代度不同的阳离子淀粉,而低取代度的阳离子淀粉又优于高取代度阳离子淀粉。当碳酸钙填加量为25%(相对于绝干浆),苯丙乳液与阳离子淀粉以1:4的比例复配,用量为2%时,虽纸张的抗张强度略有下降,但纸张的环压强度及内结合强度高于单独使用阳离子淀粉或苯丙乳液的纸张。     

两性淀粉浆料的制备及性能研究

研究采用湿法双醚化和氧化降解制备的季铵型羧甲基两性淀粉浆料性能。试验制备了季铵型羧甲基两性淀粉,测试了不同黏度、取代度、pH值条件下两性淀粉的浆液及浆膜性能,并比较了阳离子淀粉、羧甲基淀粉和两性淀粉的浆膜性能以及对纯棉纱和涤棉纱黏附性。结果表明:两性淀粉具有高浓低黏浆料特征,其黏度热稳定性和成膜性良好;随着黏度下降,浆膜断裂强度及断裂伸长率降低;随着阴、阳离子取代度的增加,浆料黏度热稳定性逐步提高,阳离子取代度在0.02~0.03、阴离子取代度在0.03~0.04范围内的两性淀粉浆膜性能较理想;pH值在中性条件下,浆膜断裂强度较好;两性淀粉的浆膜性能均优于阳离子淀粉及羧甲基淀粉;两性淀粉浆料对棉纱、涤棉纱的黏附性能优于其他变性淀粉浆料。认为:季铵型羧甲基两性淀粉能够满足纯棉纱和涤棉纱的上浆要求。     

季铵醚化阳离子改性对磷酸酯淀粉浆料上浆性能的影响

为提高磷酸酯淀粉浆料的使用性能,通过改变3-氯-2-羟丙基三甲基氯化铵醚化剂对磷酸酯淀粉的投料比,制备了一系列具有不同季铵阳离子取代度的磷酸型两性淀粉.研究了其浆液性能以及对棉纤维粘附性能的影响,探讨了淀粉浆料对纯棉经纱的上浆性能.结果表明:随着季铵阳离子取代度的增加,变性淀粉浆液的ζ电位升高,粘度明显提高;季铵阳离子化变性能够进一步改善磷酸酯淀粉对棉纤维的粘附性能,提高淀粉浆料对纯棉经纱的上浆性能.     

取代度对阳离子淀粉性能的影响试验

对不同取代度的阳离子淀粉的糊化温度、粘度、粘着力、耐磨性能和浆膜吸湿性能等指标进行了测试分析,得出了取代度变化对浆料性能的影响规律,并指出:由酸解淀粉制取的阳离子淀粉对纯棉纱的粘着力大于由玉米原淀粉制取的阳离子淀粉;阳离子淀粉的取代度控制在0.05左右为宜.     

电导率和取代度对阳离子淀粉增强作用的影响

自行合成不同取代度的季铵型阳离子淀粉,用氯化钠调节浆料的电导率,探讨不同浆料电导率和阳离子取代度对系统Zeta电位、纸张的环压强度和耐破指数的影响.结果表明,阳离子淀粉的取代度越高,系统的Zeta电位变化越大,纸张环压指数和耐破指数提高幅度越大;电导率对添加低取代度阳离子淀粉的系统Zeta电位影响较大,对添加高取代度阳离子淀粉的Zeta电位影响较小,在取代度相同的情况下,电导率对纸张环压指数和耐破指数的影响不明显.     

阳离子淀粉作为固色剂对纸张固色效果的研究

为了改善食用色素中的靓蓝色素在纸张上的固色效果,在浆外染色过程中添加阳离子淀粉,探究了阳离子淀粉在纸张表面固色的机理,以及不同取代度阳离子淀粉的固色效果,并确定了最优固色工艺。采用单因素实验探究了阳离子淀粉的取代度、染液pH值、染液温度、阳离子淀粉用量对纸张固色效果的影响。通过光学显微镜、扫描电子显微镜观测结果推测出带负电的靓蓝色素与带正电的阳离子淀粉相互吸引而紧密结合,携带着靓蓝色素的阳离子淀粉,再与显负电的纤维紧密结合,使颜色稳定固着于纸上。结果表明,取代度越高的阳离子淀粉作为靓蓝色素固色剂的效果越好,即取代度为0. 06的阳离子淀粉固色效果最好,最佳固色条件为:染液pH值6,染液温度80℃,阳离子淀粉用量1. 5%,较不添加固色剂的空白组固色效果提升84. 4%。     

粘合剂对层间加填纸张性能的影响

实验选用滑石粉和碳酸钙为矿物填料,聚乙烯醇、苯丙乳液以及两种取代度不同的阳离子淀粉作为层间加填的粘合剂,研究了瓦楞原纸成形过程中,粘合剂与填料对成纸物理强度性能的影响。结果表明:采用聚乙烯醇及苯丙乳液作为粘合剂的效果优于两种取代度不同的阳离子淀粉,而低取代度的阳离子淀粉又优于高取代度阳离子淀粉。同时,以碳酸钙作为填料,苯丙乳液作为粘合剂进行层间加填时,采用全废纸抄造瓦楞原纸,其成纸物理强度性能优于滑石粉。且当碳酸钙用量为25%(对绝干浆),苯丙乳液用量为2%时,瓦楞原纸的抗张强度与浆内加填相比提高了23%,且未出现纸张分层现象,满足使用要求。     

磷酸酯阳离子两性淀粉印染废水处理剂的合成及应用

以低取代度磷酸酯淀粉与阳离子醚化剂为原料,合成了一种新型两性磷酸酯阳离子淀粉印染废水处理剂。通过考察醚化反应体系p H、反应时间、反应温度及醚化剂用量对阳离子取代度的影响,确定了最佳反应条件为:反应体系p H=11,反应温度40℃,反应时间6 h。并测试了不同阳离子取代度磷酸酯阳离子两性淀粉水处理剂对印染废水的色度去除率,结果表明,阴离子取代度0.036 8、阳离子取代度0.013 1的磷酸酯阳离子两性淀粉脱色效果最好。     

中温水溶淀粉浆料溶解性能影响因素分析

中温水溶淀粉浆料的溶解性能是中温浆纱的基础,为提高中温浆纱时淀粉浆料溶解性,以溶解度、抗凝沉性和透光率为表征指标,分析煮浆温度、煮浆时间、季铵阳离子淀粉取代度和DMSO用量对中温水溶淀粉浆料溶解性能的影响规律,并在小样浆纱机上进行浆纱实验.结果表明,取代度和调浆工艺参数分别是影响中温水溶淀粉浆料溶解性能的内在和外在关键因素,溶剂DMSO能有效提高中温水溶淀粉浆料的溶解性能.对于所研制的中温水溶淀粉浆料,当煮浆温度为65℃,煮浆时间为1h,DMSO用量为3%,取代度为0.078时,淀粉浆料的溶解度为92.4%,透光率为51.2%,抗凝沉性好.小样浆纱实验表明,在上述调浆条件下,中温浆纱性能与高温浆纱性能基本一致.     

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