天然高分子的静电纺丝

静电纺丝技术是一种直接且相对容易的纳米纤维制备方法.文章综述了天然高分子的静电纺丝,该技术通常采用有机溶剂制备纺丝液,如采用六氟丙醇、六氟丙酮及三氟乙酸等.天然高分子常规纺丝法所得纤维的直径通常在几微米至几十微米之间,而静电纺丝得到纤维直径在微米以下,甚至在纳米范围,大大低于常规纺丝法.静电纺丝的天然高分子纤维无纺织物在外伤敷料、组织工程支架和药物释放系统等医学领域具有许多潜在用途.     

静电纺丝制备PEI/PVA超细纤维负载纳米铑杂化材料的研究

利用NaBH4作为还原剂,表没食子儿茶素没食子酸酯(EGCG)为稳定剂,还原RhCl3水溶液制备铑纳米颗粒,并用透射电镜(TEM)研究了铑纳米颗粒的形貌.通过静电纺丝技术制备了PEI/PVA纳米纤维,并用戊二醛作为交联剂使之交联以提高其耐水性.然后在交联过的PEI/PVA纤维膜上负载铑纳米颗粒;利用傅里叶红外光谱仪(FTIR)、扫描电子显微镜(SEM)对PEI/PVA以及Rh/PEI/PVA薄膜进行了表征.结果表明:利用静电纺丝技术和复合技术可以制备PEI/PVA超细纤维负载纳米铑的杂化材料.     

核/壳结构复合纳米纤维的制备

核/壳结构的纳米纤维是一种功能化的复合纳米纤维,制备方法有化学涂覆、表面化学结合、共混静电纺丝和同轴静电纺丝等.重点介绍利用同轴静电纺丝法制备核/壳结构复合纳米纤维,综述了同轴静电纺丝核/壳结构复合纳米纤维在组织工程、药物包覆、催化和其他领域的潜在应用价值.     

静电纺丝纳米纤维的方法与应用现状

主要介绍了利用不同的静电纺丝收集装置设计得到多种排列形式的纳米纤维聚集体及聚合物纳米纤维的应用.说明了静电纺丝技术可以得到各种各样的聚集体,是目前制备纳米纤维比较有效的方法,提高了由纳米纤维制备的产品质量,可以应用于特定的改性方面.     

含纳米粉体功能性纤维的制备方法

介绍了功能性化学纤维制备过程中常用的抗菌型、防紫外线型、远红外型和导电型纳米粉体。阐述了采用静电纺丝和熔体纺丝法制备含纳米粉体功能性纤维的方法及其研究现状。静电纺丝包括共混法与纳米粒子原位合成法,熔体纺丝包括共混纺丝法与高聚物原位聚合法。纳米颗粒在纤维中的尺寸与分散性是影响纤维可纺性及纤维性能的重要因素,采用原位合成的方法可有效阻止纳米颗粒在纤维中的团聚,并通过静电纺丝制得纳米颗粒尺寸稳定且分散均匀的功能性纳米纤维。     

静电纺丝纳米纤维膜基光化学传感器的制备及其在重金属检测中的应用进展

化学传感器特别是光化学传感器已经被广泛研究,并应用于检测目标物如食品中的重金属。静电纺丝纳米纤维膜由于具有高比表面积、高孔隙率、可控性良好和易功能化等特点,可以被用来固定传感器以提高其灵敏度。本文主要综述静电纺丝纳米纤维膜基光化学传感器的制备及其在重金属离子检测中的应用进展。首先,简单介绍光化学传感器及静电纺丝纳米纤维膜基光化学传感器,随后根据其制备方法的差异分为高分子聚合物化学修饰法、高分子聚合物物理共混法、纳米纤维化学修饰方法和纳米纤维物理吸附方法4类,并分别综述其制备得到的静电纺丝纳米纤维膜基光化学传感器应用于重金属检测的进展,这4类方法各有优势,都具有较好的应用前景。本文将为静电纺丝纳米纤维膜基光化学传感器用于目标物的检测提供指导。     

静电纺丝食品级天然高分子研究进展

静电纺丝技术是利用高压电场使高分子溶液在喷射过程中形成纳米级纤维丝的过程。由于纳米级纺丝能够赋予材料不同于普通纤维的性质,因此静电纺丝技术越来越受到食品行业的关注。本文简要介绍静电纺丝技术原理,概述天然高分子静电纺丝的研究进展。食品级天然高分子通常分为蛋白和多糖两大类;主要介绍蛋白类天然高分子中的胶原蛋白、明胶、玉米醇溶蛋白、乳清蛋白以及多糖类的壳聚糖、纤维素、海藻酸钠、葡聚糖的电纺研究进展。     

批量制备静电纺有序纳米纤维的研究进展

静电纺丝是一种常用且有效地制备纳米纤维的方法,但其制备的纳米纤维多为无序排列结构,具有各向同性、力学性能较差等缺陷,限制了纳米纤维的应用.因此,对静电纺丝装置进行相应的改进,从而得到具有各向异性且力学性能较好的有序纳米纤维,可进一步拓宽纳米纤维的应用领域.此外,传统单针头静电纺丝技术制备效率低,使得静电纺有序纳米纤维产...     

一种基于非局部理论的静电纺丝纤维拉伸变形力学模型研究

静电纺丝法制备出的高分子纤维直径一般处于纳米级或者微纳米级,微尺度纤维材料的力学性能表现出与其特征长度的相关性。为了研究分析静电纺丝纳米纤维的尺度效应,根据非局部理论计算出静电纺丝纤维在轴向载荷作用下的应变能,进而分析纤维的位移、应变及总伸长量受非局部效应的影响规律,推导出静电纺丝纤维表关弹性模量的力学模型。结果显示,静电纺丝纤维长度越短,非局部效应的影响越明显,当纤维长度逐渐增长,非局部效应的影响逐渐减弱。该模型为高分子纳米纤维材料的力学特征研究提供理论分析工具,有望用于分析静电纺丝纤维材料变形过程中的力学行为特征。     

静电纺丝技术在食品领域的应用

静电纺丝是一种利用静电作用力将高分子聚合物转变成微纳米级超细纤维的技术。随着静电纺丝技术的不断发展,近年来其在食品领域的应用也受到越来越多的关注。本文首先简要介绍静电纺丝纳米纤维形成原理,影响静电纺丝的主要溶液参数及工艺参数。之后详细介绍静电纺丝在食品领域的应用,包括在抑菌、抗氧化活性包装,生物活性物质、脂肪和益生菌保护,以及酶的固定化等方面的应用,并分析未来静电纺丝在食品领域的发展方向。     

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