不同维度纳米纤维素基复合材料的制备及其在储能器件中的应用

纳米纤维素是一种可持续的绿色纳米材料,独特的结构使其成为发展下一代高效、环保储能器件的新选择。采用原位聚合、共混、层层自组装等方法可将纳米纤维素与碳材料、导电高分子、无机纳米粒子、过渡金属氧化物等光电材料复合形成具有导电和储能效应的多功能纳米复合材料。本文对不同维度的纳米纤维素基复合材料的制备方法及其在储能器件中应用的最新研究进展进行了综述并介绍了纳米纤维素基复合材料在储能领域未来发展中亟待解决的问题和发展方向及重点。     

纳米纤维素基抗菌复合材料及其在食品包装中的研究进展

纤维素是自然界储量最高的天然高分子材料,在能源问题日益严峻的今天,纤维素类材料越来越受到人们的关注。近年来,纳米纤维素因具有优异的机械强度和化学稳定性,同时还具有轻质、广泛的可利用性、可再生性和生物降解性等特点,已成为纳米技术领域的研究重点之一。在众多纳米纤维素基复合材料的研究中,纳米纤维素基抗菌复合材料以其优良的抗菌性能、潜在的实用性而受到广泛关注,在包装材料领域的应用方面具有很大的潜力。本文主要从纤维素和纳米纤维素的特性,以及常见用于与纤维素复合的抗菌剂种类论述纳米纤维素基抗菌复合材料的研究进展,并总结这类复合材料在食品包装领域的应用现状。     

纳米纤维素增强树脂基复合材料的研究进展

纳米纤维素作为一种绿色环保、可再生的新型功能高分子纳米材料,由于其具有密度低、比表面积大、刚性大等诸多优点,近些年来被广泛应用于树脂材料增强领域。本文首先介绍了纳米纤维素的种类及特性并例举了其在国内外几类常见树脂增强领域中的应用研究进展,其次探讨了纳米纤维素增强复合材料制备的关键因素,为纳米纤维素在相关领域的进一步应用和发展提供了参考,最后展望了纳米纤维素作为树脂增强材料的发展前景。     

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。     

纳米纤维素的制备及其复合材料的应用研究进展

纳米纤维素包含纳米纤维素晶体、纳米纤维素纤维和细菌纳米纤维素3种类型。由于其具有高强度、大比表面积、高透明性等优良性能,成为目前纳米材料领域研究的热点。本文综述了近年来国内外纳米纤维素的主要制备方法,并对纳米纤维素在复合材料领域中的应用研究进行了总结。     

纳米纤维素/MXene多功能电磁干扰屏蔽复合材料的研究进展

电磁干扰（EMI）屏蔽材料在日益密集的电磁环境中显得尤为重要。纳米纤维素具有低密度、优异的力学性能、高度的结构稳定性和热稳定性等特点;MXene具有类金属的高电导率、大纵横比、高比表面积及优良的电化学特性等优点。因此,将纳米纤维素与MXene复合能够制备高性能EMI屏蔽复合材料。本文对不同维度纳米纤维素/MXene EMI屏蔽复合材料的制备方法进行综述,包括宏观复合纤维、薄膜和气凝胶复合材料,重点总结了纳米纤维素/MXene EMI屏蔽复合材料的多功能性应用,包括光热转化、储能和柔性传感等,并对其发展进行了展望。     

纤维素基纳米复合材料在储能领域的应用研究进展

纳米纤维素是一种通过物理、化学或生物手段从原纤维材料中分离出的直径为纳米级的纤维素材料。因制备工艺的不同,纳米纤维素材料具有不同的性质特点,在未来储能领域具有更加广阔的应用前景。本文概述了近年来各类纳米纤维素基复合材料在储能领域的新进展（包括超级电容器、锂离子电池（LIB）、锂硫（Li-S）电池）,并展望了其发展前景。     

纳米纤维素的改性及其在复合材料中的应用进展

作为一种新型的纳米生物材料,纳米纤维素具有广阔的应用前景。本文给出了纳米纤维素的定义和分类,分析了其优良特性,详细介绍了对纳米纤维素进行化学改性的方法：小分子化学修饰和接枝共聚,综述了纳米纤维素在增强合成高分子材料和天然高分子材料及其衍生物中的应用进展,并对纳米纤维素在复合材料中的应用前景进行了展望。     

纳米复合阻燃材料的制备方法及其在纺织上的应用

纳米复合阻燃材料是将纳米技术应用于阻燃材料而制得的一种新型功能复合材料．概述了纳米复合阻燃材料的制备方法及其在纺织领域的应用，并对其中的PLS纳米复合阻燃材料的阻燃机理、结构和阻燃性能的表征进行了评述．     

纤维素基有机-无机纳米光催化复合材料制备及其水处理应用的研究进展

为改善传统纳米粉体光催化剂易团聚导致催化活性降低,且难以重复利用等问题,针对性地开发具有高活性位点暴露、高分散性和稳定性的纤维素基光催化复合材料是推动光催化技术产业化应用的有效途径。综述了国内外纤维素基有机-无机纳米光催化复合材料的研究进展。首先从纤维素的不同制备形态角度出发,分析了纳米纤维素、纤维素膜材料、纤维素气凝胶材料与纳米光催化材料的设计合成与制备机制,重点阐述了其在环境领域的最新应用进展,最后提出纤维素基光催化材料的发展前景以及存在的问题与局限性,为纤维素基功能材料今后的规模化制备和在环境修复材料领域的广泛应用提供参考。     

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.     

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.     

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.     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.