静电纺丝素/壳聚糖纳米纤维的研究

以质量分数为98％的甲酸为溶剂．丝素和壳聚糖以不同质量分数及比例共混制备纺丝液进行静电纺丝,并用扫描电镜观察其形态结构。结果表明：与丝素和壳聚糖溶液质量比为70／30．两者质量分数分别为13%～17％和3%～5%时,都能获得连续纤维;当丝素和壳聚糖溶液质量分数分别为17％和4%,两者质量比高于50/50时．均能静电纺得连续纤维,纤维直径随壳聚糖含量的增加而减小．减小质量比低于50／50时,制成的纳米纤维中含有壳聚糖颗粒。采用红外光谱法测定了丝素,壳聚糖纳米纤维的结构,结果表明：壳聚糖与丝素之间有相互作用,经乙醇处理促进了丝素构象转变为β结构。     

丝素与明胶共混静电纺丝

 丝素和明胶以不同质量比共混于甲酸溶剂,将此纺丝液进行静电纺丝,并用扫描电镜观察其形态结构,分析探讨了工艺参数对其形貌和直径的影响,并与相同工艺条件下的纯丝素纳米纤维进行比较。结果表明:在丝素与明胶质量比为70∶30,纺丝液质量分数为11%,极距为13 cm,电压为22 kV的工艺条件下,静电纺纤维平均直径为83.9 nm,纤维直径分布均匀。用明胶共混不仅有利于克服低质量分数丝素纺丝液静电纺丝中出现的珠状物和断头多等问题,而且有望应用于生物组织工程中。     

静电纺再生丝素纳米纤维形态结构的研究

以98％甲酸为溶剂溶解再生丝素室温干燥膜后,采用静电纺丝纺制丝素纳米纤维;采用扫描电镜观察其形态结构：研究并分析了纺丝液质量分数、电压、喷丝头到收集网的距离、纺丝管口径对纤维直径及形态的影响。结果表明：质量分数为11％-19％的纺丝液静电纺丝均能获得丝素纳米纤维,质量分数为11％、13％,电压为32kV,固化距离为7cm时,能够获得平均直径分别为91、96nm的纳米纤维：纤维直径随纺丝液质量分数的增加而增大,随电压的增大而减小,可根据纺丝液质量分数和电压选择合适的固化距离和管口径。     

静电纺丝素纳米纤维非织造膜形态结构研究

静电纺丝可获得丝素纳米级纤维,并以非织造布状排列,广泛用于细胞支架、伤口包覆及药物控释等。用甲酸溶解丝素室温干燥膜,研究了静电纺丝素纳米纤维非织造膜的形态结构,分析其影响因素。结果表明:非织造膜孔隙率为32.3%,孔径80~600 nm;纤维直径与纺丝液质量分数表现出高度显著线性关系,纤维直径随纺丝液质量分数的升高而增大;纤维直径开始随电压的增大而变小,之后变大;电场强度相同,高电压/长距离电场形成的纤维直径小。     

静电纺再生丝素/明胶纳米纤维的结构与性能

 以质量分数为98%的甲酸为溶剂,将再生丝素与明胶以质量比70∶30进行共混静电纺丝。研究纺丝液质量分数及乙醇处理对纤维膜的结构及力学、溶解性能等的影响;测定不同纺丝液质量分数及不同厚度下纤维膜的孔隙率及孔径;在纤维膜上进行小鼠成纤维细胞(L929)和人脐静脉内皮细胞(HUVECs)培养实验。结果表明:随着纺丝液质量分数的提高或经乙醇处理后,丝素β化程度提高,纤维结晶度增大,溶失率减小,拉伸强度增大;随着纺丝液质量分数的提高,纤维膜的孔隙率减小,孔径增大,厚度增加时,纤维膜的孔隙率及孔径均减小;L929及HUVECs均能够在纳米纤维膜上黏附、生长和增殖。     

静电纺再生丝素纳米纤维载药体系研究

将丝素和药物双胍醋酸盐共溶于质量分数为98%的甲酸,制得均匀的纺丝液,再静电纺丝制备丝素/药物纳米纤维膜。扫描电镜(SEM)观察其形貌的结果表明:纳米纤维的平均直径随着含药量的增加而减小;随着丝素质量分数的增加而增加。通过紫外分光光度计测其释放在水中药物的吸光度来计算释药速率,其释药速率随纤维直径的减小而加快。抑菌圈定性测试显示丝素/药物纳米纤维膜对金黄色葡萄球菌和大肠杆菌具有优异的抑菌性。     

静电纺再生丝素蛋白纳米纤维膜的工艺及性能

以甲酸为溶剂,利用静电纺丝法制备了再生丝素蛋白纳米纤维膜,系统地研究了纺丝液质量分数,纺丝电压、纺丝液流速及接收距离对纤维形貌和直径的影响.结果表明,在制备直径250 nm以下、表面光滑且均匀的纤维时,纺丝液质量分数和电压是影响纤维形貌和直径的2个主要因素,且体积分数90%乙醇溶液处理能促进丝素蛋白纤维的结构从无规卷曲...     

静电纺丝素-透明质酸共混纳米纤维形态结构研究

以甲酸为溶剂,采用静电纺丝方法制备丝素蛋白(SF)与不同相对分子质量的透明质酸(HA)共混纳米纤维,并通过扫描电镜(SEM)、红外光谱(FTIR)、X射线衍射(XRD)和热分析(TG-DTA)研究了SF-HA共混纳米纤维非织造网的形态、结构和性能。结果表明:通过静电纺丝,丝素与低分子量的透明质酸共混纳米纤维直径在100 nm左右,纤维表面光滑,呈圆柱状;高分子量透明质酸的加入使得纤维形态变差,出现严重的粘连现象;透明质酸的加入未对丝素分子构象和结晶结构产生明显影响。     

聚苯乙烯微纳米纤维膜的液喷纺丝制备工艺研究

本文以聚苯乙烯/二氯甲烷体系为纺丝液,使用普通市售喷笔,采用液喷纺丝法制备了聚苯乙烯微纳米纤维膜,探究了不同溶液质量分数、气流风压和纺丝距离对纤维直径及其孔隙率的影响。结果显示,所得微纳米纤维膜直径在200~1 600 nm内,纤维直径随溶液质量分数和纺丝距离的增大而增大,随风压的增大而减小。通过正交实验研究发现,不同条件对纤维直径和孔隙率的显著影响顺序为:溶液质量分数风压纺丝距离。     

PU/PVDF防水透气共混膜的制备及性能研究

采用静电纺丝法制备聚氨酯/聚偏氟乙烯(PU/PVDF)共混纳米纤维膜,研究PU、PVDF质量分数、溶剂体积配比、溶质质量比对纳米纤维形貌、直径及膜性能的影响,探索共混纤维膜较优制备工艺。结果表明:共混纳米纤维膜较优制备工艺为静电纺丝电压14 kV、接收距离10 cm、纺丝液质量分数12%、溶剂体积配比N,N-二甲基甲酰胺/丙酮为4/6、溶质质量比PU/PVDF为7/3,此条件下可获得具有较优防水透气性能和力学性能的共混膜。     

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