基于静电纺纳米银/聚氨酯复合膜的制备及性能

以水性聚氨酯为分散体系,硼氢化钠为还原剂,硝酸银为前驱体,利用化学原位还原法制备纳米银溶液,所制备的纳米银粒子粒径在10 nm左右。将制得的纳米银溶液与聚氨酯溶液混合后,通过静电纺丝的方法制备了三种不同载银量的载银纳米纤维膜。结果显示,将300μL的4 000 mg/kg纳米银溶液加入到由150 mL丙酮和N,N-二甲基甲酰胺（DMF）（体积比1∶1）混合溶剂溶解的质量分数为25%的热塑性聚氨酯弹性体（TPU）溶液中,通过静电纺制备的纳米纤维膜对大肠埃希菌和金黄葡萄球菌的抑菌率达99.99%,表现出优异的抗菌性能。     

载银PAN纳米纤维膜的制备及其抗菌性能研究

以乙二胺和丙烯酸甲酯加成聚合制备端氨基超支化聚合物(HBP),再以超支化聚合物作为还原剂和稳定剂制备粒径约为10 nm的纳米银溶液。以N,N-二甲基甲酰胺(DMF)为溶剂溶解聚丙烯腈粉末(PAN),采用高压静电纺丝技术制备了直径为数百纳米的PAN纳米纤维膜,并用所制备的纳米银溶液对PAN纳米纤维膜进行抗菌整理。研究显示,低温下纳米银颗粒较难负载于PAN纳米纤维膜上。当处理温度上升至90℃时,纳米纤维膜上的载银量可达10%以上。载银PAN纳米纤维膜具备良好的抗菌性能。     

纳米银/纳米二醛纤维素气凝胶的制备及表征

使用漂白硫酸盐针叶木浆为原料,以经高碘酸钠氧化后制备出的二醛纤维素为基材负载纳米银颗粒,后经高压均质法得到载银量为24.78%的纳米银/纳米二醛纤维素气凝胶。探讨高碘酸钠氧化反应时间对构成漂白硫酸盐针叶木浆的纤维素大分子以及针叶木纤维的影响。通过傅里叶变换红外光谱仪、X射线衍射仪、紫外可见分光光度计、扫描电子显微镜、透射电子显微镜和比表面积和孔径分析仪对样品进行表征。结果表明,随着氧化时间的增加,纤维素的醛基含量持续上升,当反应4 h时增至330 μmol/g,纤维的聚合度由1447大幅下降至525,同时零距抗张强度和长度也呈现下降趋势。制备出的载银气凝胶上负载的纳米银颗粒为球形,气凝胶的比表面积为35.40 m~2/g,平均孔径为19.62 nm。     

载银海藻酸钙纤维水刺非织造布的制备及其抗菌性能

利用氨基纳米银溶液对海藻酸钙纤维水刺非织造布进行浸渍处理,制备载银海藻酸钙纤维水刺非织造布,对浸渍处理前后的表面形貌、成分、载银量、吸液性能和抗菌性能进行测试分析。结果表明,海藻酸钙纤维水刺非织造布能吸附氨基纳米银溶液中的银颗粒且银颗粒均匀地分布在海藻酸钙纤维表面;载银海藻酸钙纤维水刺非织造布的吸液率最高可达到20.590 g/g,对金黄色葡萄球菌和大肠埃希氏菌的抗菌率均达到99.00%以上。     

葡聚糖纳米银的制备及其对丝绸织物的抗菌整理

以葡聚糖作为还原剂和模板,通过和硝酸银溶液反应制得稳定的纳米银溶胶抗菌剂。利用紫外-可见分光光度计(UV-Vis)、透射电镜(TEM)和X射线粉末衍射仪(XRD)表征了所制备的纳米银;利用纳米银溶液对桑蚕丝织物进行了载银抗菌处理,并测定了处理后织物的抗菌性能、白度及耐洗性;探讨了蚕丝纤维对纳米银颗粒的吸附机理。采用扫描电镜(SEM)观察载银整理后纤维表面纳米银颗粒的分布和形貌。试验结果表明,当硝酸银用量为0.5 mL时,制得溶胶中纳米银的粒径大小在20~30 nm,放置两个星期后,纳米银溶液仍然保持透明澄清,无沉淀。利用制备的纳米银溶液采取二浸二轧法对丝织物进行整理,整理后织物对金黄色葡萄球菌和大肠杆菌的抑菌率分别为98.32%和98.53%,经过30次洗涤后,对金黄色葡萄球菌和大肠杆菌的抑菌率仍能达到95%以上,具有良好的耐洗性能。     

陈皮提取物纳米银的合成及性能

为了获得一种绿色环保、低能高效的纳米银制备方法,选用陈皮提取液为还原剂和保护剂,采用生物合成法制备纳米银胶体。研究了反应温度、陈皮提取液添加量、硝酸银溶液添加量、反应时间对纳米银胶体粒径和形貌的影响。通过紫外可见分光光度计、纳米粒度仪和透射电镜对制备的纳米银颗粒进行表征。结果表明：利用陈皮提取液及硝酸银可以制备得到纳米级的银胶体。当反应温度为80℃,硝酸银溶液体积为7 mL,陈皮提取液体积为20 mL,反应时间为30 min时,纳米银生产效率高、粒径小,且形貌规则,近球形,稳定性较好。     

海藻酸钠-纳米纤维素胶粒对乳酸菌胃肠液耐受性的影响

为提高海藻酸钠胶粒对乳酸菌在胃肠液中的保护作用,分别利用豆渣纤维素纳米微纤丝与纤维素纳米微晶协同钙离子交联海藻酸钠包埋乳酸菌制备载菌海藻酸钠-纳米纤维素胶粒,并对海藻酸钠-纳米纤维素胶粒进行微观结构观察、傅里叶变换红外光谱分析、低频氢谱核磁共振分析,同时测定载菌海藻酸钠-纳米纤维素胶粒胃肠消化前后的活菌数量,研究海藻酸钠-纳米纤维素胶粒对乳酸菌胃肠液耐受性的影响。结果表明,纳米纤维素可提高海藻酸钠胶粒的包埋率并减少胶粒表面的孔隙结构,纳米微纤丝较纳米微晶能更好地改善海藻酸钠体系的氢键结合能力,促进海藻酸钠分子链与Ca2＋间形成盐桥,强化凝胶体系的网络结构,从而提高海藻酸钠胶粒的机械强度。进一步研究发现,海藻酸钠-纳米微纤丝胶粒经胃肠液消化后活菌数下降1.51（lg（CFU/g））,显著低于纳米微晶组（2.16（lg（CFU/g）））以及海藻酸钠组（2.99（lg（CFU/g）））（P＜0.05）。综上,纳米微纤丝可作为强化海藻酸钠载体的优良壁材提高乳酸菌的胃肠道耐受性。     

自还原法制备纳米银抗菌棉织物工艺初探

通过利用纤维素纤维自身对银离子的吸附性和还原性,尝试直接利用硝酸银溶液与棉织物反应制备纳米银抗菌棉织物,用扫描电子显微镜(SEM)、紫外分光光度计、电感耦合等离子体(ICP)对制备的纳米银抗菌棉织物进行表征;考察了反应温度、时间、浴比、硝酸银溶液浓度等因素对制备纳米银织物银含量的影响。结果表明,自还原法可制备纳米银抗菌棉织物,织物表面负载的银粒子尺寸为10～140 nm,且自还原法相对工艺简单,能够降低环境污染和减少浪费。     

TiO_2/纤维素多孔三维材料的制备及其在染料分解中的应用研究

以微晶纤维素为原料,通过LiCl/DMAc体系对微晶纤维素进行溶解,然后采用不良溶剂诱导相分离的方法制备纤维素多孔三维材料。所得材料具有三维连通的多孔结构,且材料内部孔以介孔居多,具有密度小、孔隙率大等优点,能够作为复合材料的基质广泛应用。将TiO_2纳米颗粒与纤维素多孔三维材料复合制得TiO_2/纤维素多孔三维材料,所得材料中TiO_2纳米颗粒在三维空间内分布均匀。TiO_2/纤维素多孔三维材料在紫外光照射下对亚甲基蓝溶液具有优秀的光催化降解性能,且能够多次重复利用。     

酶解辅助高压均质制备纳米纤维素及其性质表征

本研究以微晶纤维素为原料,经过超微粉碎预处理后,通过酶解辅助高压均质的方法制备纳米纤维素,研究纳米纤维素的结构和理化性质,并通过扫描电镜、透射电镜、红外光谱、X-射线衍射和热失重分析对纳米纤维素进行表征。结果表明,超微粉碎前处理能使微晶纤维素颗粒大小形状趋于均一化;所制备的纳米纤维素呈束状结构,颗粒直径为15~40 nm;纳米纤维素在制备过程中纤维素结构未遭到破坏;纳米纤维素的结晶度为58.1%,仍属于纤维素Ⅰ型;纳米纤维素的起始热分解温度比微晶纤维素的分解温度低,当温度达到500℃时,纳米纤维素的热失重率为82.9%。因此通过酶解辅助高压均质制备的纳米纤维素有望在可降解复合材料中得到应用。     

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