纳米纤维素制备的研究进展

近年来,资源与环境问题越来越受到人们的关注。开发利用可再生资源以替代煤、石油等化石资源成为必然的趋势。天然纤维是自然界中分布最广的可再生的生物高分子物质。由其制备得到的纳米纤维素是一种绿色、环境友好的纳米材料,具有一些独特的性能,如可再生、可生物降解及良好的机械性能等。纳米纤维素的制备研究对新型材料的发展具有重要的意义。本文介绍纳米纤维素的制备方法及研究进展。     

Fe_3O_4/Au磁性复合材料的制备及表征

本文首先通过多醇法制备粒径可控的四氧化三铁纳米粒子,通过硅烷偶联剂对四氧化三铁纳米粒子进行胺基化修饰,胺基化修饰四氧化三铁纳米粒子与羧基表面的Au纳米粒子通过静电相互作用制备得到Fe_3O_4/Au复合纳米材料。透射电子显微镜、红外光谱仪、能谱仪等表征揭示成功制备具有core-/Satelite结构Fe_3O_4/Au复合纳米材料。     

纳米木素的机械法制备研究进展及其应用前景

木素是自然界中一种储量丰富且可再生的生物质资源,已经得到了人们的广泛关注。但木素资源却并未得到高效的利用,而纳米木素为木素的高值化利用提供了一条崭新的途径。本文介绍了纳米木素的机械法制备,包括高剪切均质法、超声波法、球磨法及这几种方法结合的方法,并对纳米木素在紫外防护、抗菌、吸附、纳米复合材料和生物医学等领域中的应用进行了综述和展望。     

纳米银在TEMPO催化氧化黄麻纤维上的微波原位合成

金属纳米粒子一纤维素复合材料是一种具有生物相容性和抗菌性的可再生纳米材料,由于其应用功能广泛而备受关注。本文首次研究了不使用还原剂条件下’采用微波原位合成法在丁EMPO（2,2,6,6一四甲基哌啶氧化物自由基）选择性氧化黄麻纤维上简便、快速制备银纳米粒子。微波加热5min,纤维上的银纳米粒子平均尺寸为50．0±2．0hm,而加热10min则为90．0±4．7nm。该多功能黄麻一银纳米粒子复合物具有优异的热稳定性和高结晶度。     

木素-二氧化硅纳米复合物制备与表征初步探索

以玉米秸秆发酵生产纤维素乙醇得到的残渣为原料,Na OH为溶剂,HCl为酸沉淀剂,利用酸沉淀法制备木素-二氧化硅纳米复合物。采用红外光谱、扫描电镜(SEM)、热重检测(TGA)和粒径测定等手段,研究反应体系p H值和温度对复合物形貌、组成成分及含量的影响,确定制备木素-二氧化硅纳米复合物的最佳工艺条件。结果表明,当反应温度30℃、p H值7时,制备出的复合物中二氧化硅的质量分数为75.05%,且复合物分散性较好,比木素具有更好的热稳定性。通过粒径分布分析,制备的木素-二氧化硅纳米复合物粒径为95 nm的粒子数量占20.2%。     

纳米纤维素的制备策略及应用实践

纳米材料因其具有比表面积大、力学强度高、热性能好等独特优势,还具有原料可再生、产品可降解、生物相容性好等特点,因此成为研究的热点。对纤维素纳米晶体(CNC)、纤维素纳米纤丝(CNF)和细菌纳米纤维素(BNC)3种主要纳米纤维素的结构特征,不同纳米纤维素的制备策略作了介绍,结合纸基材料、复合材料、储能材料、医学材料等领域的发展现状,综述纳米纤维素在新兴领域的应用研究进展,并对纳米纤维素的未来发展趋势进行展望。     

贵金属纳米粒子/碳量子点复合材料的制备及应用

贵金属纳米粒子/碳量子点纳米材料结合了贵金属纳米粒子和碳量子点的优点,是一种非常有前途的功能材料。近年来,国内外对其制备方法及应用研究逐渐增多,已广泛应用于表面增强拉曼光谱、传感、催化和抗菌等方面。碳量子点表面含有丰富的基团,既可以作为电子供体也可作为电子受体,在贵金属纳米粒子的制备中已经得到了很好的应用,制备过程高效、环保且形态可控。本文概述了近年来银纳米粒子/碳量子点和金纳米粒子/碳量子点复合纳米材料的制备方法及其应用,并对前景进行了展望。     

上转换纳米粒子在食品分析中的应用研究进展

上转换纳米粒子由于其诸多优点已发展成为一类新兴的荧光生物探针和光学分析纳米材料。上转换纳米粒子因其具有毒性低、成本低、生物相容性好、化学稳定性好等优点,被广泛应用于各个领域。上转换纳米粒子具有独特的发光形式,它将低能辐射转化为高能辐射,和传统的染料和量子点等依靠下转换的发光材料相比,它可以通过近红外光激发,因此在生物医学及食品分析中有其不可比拟的优点。综述上转换纳米粒子的特性和制备方法,着重介绍近年来上转换纳米粒子在食品毒素、食源性致病菌、氨基酸、维生素和微量元素的快速高效检测中的研究进展,并对上转换发光纳米材料的应用前景进行分析和展望。     

激光烧蚀银等离子体特性分析

金属纳米材料因具有的独特的表面效应、小尺寸效应和量子效应,使得金属纳米材料在光学、电学、磁学、生物医学、传感等多个方面得到了广泛的开发和利用。其中Au、Ag金属纳米材料因为其具有优良的物理化学特性,逐渐成为基础研究领域的热门方向。文章首先介绍了激光烧蚀法制备银纳米粒的制备方法,通过对银纳米粒子的特性进行分析,描述了其在光学、抗菌、催化等方面的优异特性。最后浅谈了金属纳米材料在催化,磁性,生物学方面的应用及发展前景。     

纳米技术在造纸工业中的应用

正近年来纳米材料在造纸中的优势越来越显著,对其应用研究也越来越热。由纳米粒子改性的纸张逐渐在市场中崭露头角,纳米纸与普通纸在外观上并没有什么区别,但是在性能上却有很大的不同。造纸工业中应用的纳米材料主要有:纳米纤维素、无机纳米粒子(如纳米SiO_2、TiO_2、CaCO_3、Ag等)以及有机胶乳纳米粒子等。1纳米技术简介纳米技术是指在纳米尺寸(0.1~100n m)范围内,探讨物质(电子、原子和分子内)的移动规则和特征的一种新技术。而由纳米技术制备的纳米材料是指在三     

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