多羧基纤维素纳米晶的制备与性能研究

采用乙二胺四乙酸二酐（EDTAD）酯化法制备表面羧基含量及羟基取代度可控的多羧基化纤维素纳米晶（ECNC）,并通过改变酯化条件,优化实验结果;通过傅里叶变换红外光谱（FT IR）、透射电子显微镜（TEM）、电导滴定、X射线衍射（XRD）、元素分析、Zeta电位等对ECNC进行分析。结果表明,ECNC保持了CNC的形貌和结晶结构完整性,并且在水和磷酸盐（PBS）缓冲溶液中的分散性较CNC显著提高;同时,通过改变酯化反应条件可控制ECNC表面羧基含量及羟基取代度。该ECNC颗粒有望用于高性能复合纳米材料的制备及功能化纳米复合颗粒的制备中。     

LPMO结合硫酸水解制备纤维素纳米晶体

以棉溶解浆为原料,使用裂解性多糖单加氧酶（LPMO）预水解结合硫酸水解制备纤维素纳米晶体（CNC）,对LPMO预水解前后纤维的微观形态和制得的CNC进行了粒径、结晶度和微观形态等表征,并与仅硫酸水解制备的CNC进行对比。研究发现,采用质量分数60%硫酸水解时,经LPMO预水解得到的CNC比仅硫酸水解制备的CNC平均粒径减少22 nm,结晶度提高8.8个百分点,得率提高19.3个百分点。在LPMO预水解后,随着硫酸质量分数降低,CNC的得率和羧基与磺酸基总量减少,粒径上升,而结晶度无明显正比关系。从LPMO作用整体效果来看,预水解结合50%硫酸得到的CNC与对照组相比粒径增加9 nm,羧基和磺酸基总量略小,而结晶度提高6.4个百分点,得率提高18.4个百分点,其原子力显微镜（AFM）表征显示已达到纳米水平。故通过LPMO预水解结合50%硫酸即可制得CNC,这可降低对工业生产上设备耐酸能力的要求。但LPMO反应周期长,因此在实际工业应用中有待进一步研究。     

茶梗制备纤维素纳米晶体及其表征

以茶梗为原料,采用硫酸水解法制备纤维素纳米晶体（CNC）,并运用响应面分析法对CNC制备工艺（即硫酸质量分数、反应温度和反应时间）进行优化;采用透射电子显微镜（TEM）、热重分析仪（TG）和X射线衍射仪（XRD）对CNC的形貌、热力学性能、结晶结构和结晶性能进行表征。结果表明,制备茶梗CNC的最佳反应时间125 min,温度45℃,硫酸质量分数为63%;在最佳工艺条件下获得的CNC的得率为49.9%,其为棒状,直径4~8 nm,长度100~250 nm,属纤维素I型;与茶梗纤维相比,茶梗CNC结晶度提高,热稳定性降低。     

硫酸水解辅助高压均质法制备小麦秸秆纳米纤维素

以小麦秸秆纤维素为原料,通过硫酸水解辅助高压均质的方法,分层制备小麦秸秆纳米纤维素（CNC）;分别采用马尔文纳米粒度分析仪、透射电子显微镜、原子力显微镜、傅里叶变换红外光谱仪、X射线衍射仪和热重分析仪对分层制备的小麦秸秆CNC进行表征分析。结果表明,经硫酸水解预处理、离心收集得到的上层清液纳米纤维素（CNC-SL）为纳米纤维素晶须,与原料相比,其结晶度由48.61%提高至71.87%;硫酸水解预处理、离心收集的残余纤维固体（CNC-S）经8次均质处理制备的纳米纤维素（CNC-SP）,其粒径分布在100~200 nm,直径约为15 nm,为高结晶度的短棒状纳米纤维素晶须,晶型为I_β型。与原料相比,CNC-SL和CNC-SP的热稳定性均下降。与硫酸水解法制备CNC相比,硫酸水解辅助高压均质法制备的CNC得率较高;与机械均质化方法相比,此方法所需均质次数明显减少。     

NaClO/CNC氧化淀粉的制备及其复合膜的性能研究

将纤维素纳米晶体(CNC)加入NaClO氧化体系制备氧化淀粉(OS),将氧化淀粉(OS)与聚乙烯醇(PVA)/甘油(GL)共混制备复合膜,3种物质的质量比为OS∶PVA∶GL=20∶8∶5;并对OS和复合膜的性能进行表征。结果表明,在CNC添加量为0. 5%时,OS的羧基含量最高为1. 1%;此时复合膜的透明度达到最高值0. 66,且复合膜的热稳定性最好;在CNC添加量为3. 0%时,复合膜的拉伸应力达到11. 89 MPa。     

纤维素纳米晶体对热升华转印纸涂层性能影响研究

本研究通过酸水解法制备纤维素纳米晶体（CNC）悬浮液,将其加入SiO₂/羧甲基纤维素钠（CMC）涂料中,形成一种热升华转印纸生物基涂层。结果表明,CNC对SiO₂/CMC团聚具有一定的分散作用。与SiO₂/CMC涂层的热升华转印纸相比,CNC添加量为2.0%的SiO₂/CMC/CNC涂层的热升华转印纸纵、横向抗张指数分别提高了9.2%、9.3%,平滑度提高了31.9%,透气度下降了46.0%,油墨吸收值下降了3.4%、干燥速度提高了24.3%,承印物平均色密度值由1.01升高至1.21,油墨转移率由80.1%升高至88.5%。由此可见,CNC添加提高了热升华转印纸的机械和热转印性能。     

羧基改性水性聚氨酯的制备及其对涤纶夜光整理的影响

通过合成不同羧基含量的聚氨酯预聚体,乳化制备了一系列水性聚氨酯（WPU）整理剂,再与长效夜光材料复配,研究了羧基含量对WPU夜光整理剂分散稳定性及荧光行为的影响。将WPU夜光整理剂采用常温浸轧工艺处理涤纶织物,测定了整理后织物的荧光行为和耐洗性。结果表明：一定量的羧基含量可以提高夜光材料在整理剂中的分散性和稳定性,但过高的羧基含量对发光强度有明显的抑制作用,会导致荧光衰减速率明显加快;WPU夜光整理织物表现出良好的发光性能、荧光半衰减时间及较佳的耐洗涤性。     

Ca2+交联羧基化麦草秸秆化机浆的制备及性能研究

本研究采用TEMPO氧化体系,转化麦草秸秆化机浆（SP）纤维素C6位上的羟基为羧基,制备羧基化麦草秸秆化机浆（CSP）;对CSP进行Ca²⁺交联,制备Ca²⁺交联羧基化麦草秸秆化机浆（CSP@Ca²⁺）,探究其纸浆的物理强度性能。基于FT-IR、XPS等手段可以明显检测CSP 纤维的羰基/羧基官能团：羧基化1 h麦草秸秆化机浆纤维（CSP1）的羧酸含量为0.27 mmol/g,其Zeta电位从SP的-21.7 mV变化为-29.2 mV,这为Ca²⁺的交联提供作用位点。纸张物理强度结果表明,CSP1@Ca²⁺0.5的抗张指数、耐破指数和撕裂指数分别较SP提高154.4%、170.8%和12.9%。最终,CSP1@Ca²⁺0.5与SP配抄纸张（配抄比例为50∶50）的抗张指数、耐破指数和撕裂指数分别达27.1 N·m/g、2.28 kPa·m²/g和3.68 mN·m²/g,较SP分别提高83.4%、115.1%和8.3%。     

CNC经ATRP接枝含胺基聚合物制备具有pH响应Pickering乳化剂

本研究对纤维素纳米晶体（CNC）进行溴代异丁基接枝,然后在甲醇-水溶剂中室温下进行原子转移自由基聚合（ATRP）,制备了含有叔胺基聚合物支链的CNC改性产物（CNC-PDMAPMA、CNC-PDMAEMA、CNC-PDEAEMA）。采用多种手段对产物进行了分析和表征,证实聚合物接枝CNC改性产物成功制备。当这3种改性产物的悬浮液质量分数为0.8%时,其表面张力分别为50.6、51.7和 54.4 mN/m,具有良好的表面活性。质量分数0.6%的聚合物改性CNC稳定的甲苯/水和庚烷/水Pickering乳液至少可以保存15天而不出现相分离。3种改性产物的水分散液具有对甲苯（庚烷）/水乳液的N₂/CO₂乳化-破乳响应性转换能力。     

深度氧化淀粉的制备及助洗性能

研究了用次氯酸钠氧化玉米淀粉制备高羧基含量的氧化淀粉并探索其在洗涤剂助洗方面的应用 .结果表明 :制备高羧基含量的氧化淀粉的最佳工艺条件为氧化剂用量 2 0 %、反应 pH为9.0、反应时间为 3.0h、反应温度为 4 5℃ ;氧化淀粉对模拟固体污垢MnO2 具有较理想的悬浮分散性及分散稳定性并具有一定的金属离子的封锁能力 .     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.