染料改性壳聚糖阴离子交换膜的制备及其性能研究

利用1-氨基蒽醌、三聚氯氰、二甲基丙二胺、硫酸二乙酯合成季铵盐阳离子活性染料LCRD,配制壳聚糖醋酸溶液,采用共混-化学交联联用法制备染料改性壳聚糖阴离子交换膜。采用交流(AC)阻抗、傅立叶变换红外(FTIR)光谱、扫描电镜(SEM)、热重分析(TGA)等分析技术考察膜的离子电导率、分子结构、微观形貌、热稳定性和耐碱稳定性等性能。试验结果表明,所制备的CTS/LCRD膜(质量比1︰0.5)电导率达到3.18×10~(-3)s/cm,将其置于KOH溶液(80℃,6 mol/L)中168 h后取出,膜的电导率未下降,相反提高到5.33×10~(-3)s/cm。     

光交联壳聚糖/聚乙烯醇共混膜的制备与性能

将壳聚糖与感光性物质混合制成感光性壳聚糖 ,再与聚乙烯醇按一定比例共混、成膜并进行光交联 ,制备了系列壳聚糖 (CTS) /聚乙烯醇 (PVA )光交联共混膜 ,并对共混膜的结构和性能进行比较 .结果表明 :重氮树脂系列CTS/PVA光交联共混膜性能优于CTS/PVA共混膜 ,且重氮树脂系列CTS/PVA光交联共混膜有其独特的表面形貌 .孔结构的大小及形态与共混膜中CTS/PVA的比例、重氮树脂的含量有关     

PVA可生物降解材料研究进展

聚乙烯醇是一种可生物降解、水溶性的聚合物,具有生物相容性能优良、易成膜、制备工艺相对简单等特点,在包装领域得到广泛应用。简述了聚乙烯醇的性能特点、降解机理、影响降解机理的各种因素;综述了淀粉、改性淀粉、壳聚糖、聚乳酸改性聚乙烯醇(PVA)制备可生物降解材料的方法与研究成果,对聚乙烯醇的研究成果进行了分析,指出低成本、力学性能优良、降解完全的PVA可生物降解改性薄膜将是今后的研究重点;聚乙烯醇/纳米黏土改性高阻隔包装材料也是主要的研究方向。     

醋酸酯淀粉/聚乙烯醇杂化膜的制备和性质

对玉米原淀粉(ST)改性,制备低取代度醋酸酯淀粉(SA),与聚乙烯醇(PVA)共混,添加纳米二氧化硅改性,经增塑后制备可降解的SA/PVA杂化膜.用红外光谱、扫描电镜对SA/PVA杂化膜进行了结构表征,结果表明SA/PVA杂化膜形成了空间网络结构,相容性较好,膜的致密性提高.电子拉力试验和水溶性试验表明该膜力学性能、耐水性能提高.土埋实验表明该杂化膜具有很好的生物降解性.     

国内PVA薄膜材料改性研究进展

聚乙烯醇(PVA)是一种性能优异、用途广泛的薄膜材料,在水溶性及可降解性等方面具有独特优点。文章对PVA的优点、特性作了简要介绍。PVA分子链上含有大量羟基,亲水性较高,在湿度较大的情况下,其阻隔性会急剧下降;PVA熔融温度和分解温度十分相近,给热塑加工带来了困难;PVA是一种可完全降解的高分子聚合物,但其薄膜生物降解周期较长;PVA用作制备亲水膜的材料,但PVA膜纯水渗透量高,其在湿态的稳定性和力学性能不佳。因此,需要对PVA进行不同的改性才能使其达到优良的性能。从PVA的耐水性和水溶性改性、热塑性加工的改性、生物降解性的改性和PVA膜渗透和稳定性改性等4方面对PVA薄膜用材料改性研究方面的进展进行了综述。     

基于废弃毛纺织物的抗菌复合纳米纤维膜的制备及性能

为制备抗菌性好、安全、成本低且性能稳定的纳米纤维,采用碱溶解-等电点沉淀法从废弃羊毛中提取角蛋白多肽链段(WK),以铜离子(Cu)为抗菌剂,加入聚乙烯醇(PVA)共纺,采用静电纺丝法制备PVA/WK/Cu纳米纤维膜。利用正交试验选出形态最佳的PVA/WK纳米纤维,再添加不同含量的铜离子进行性能测试分析。试验结果表明：当聚乙烯醇质量分数为8%,角蛋白质量分数为20%时,制备的PVA/WK纳米纤维光滑均匀。铜离子的加入对纤维平均直径影响较小,但对纤维均匀程度影响较大。红外光谱曲线发生变化的原因是受角蛋白与PVA氢键结合以及铜离子与角蛋白和PVA形成配位键的影响。由TG-DSC结果得出,角蛋白的加入在一定程度上提高了纳米纤维膜的热稳定性。对金黄色葡萄球菌进行琼脂平皿扩散法测试,纤维膜表现出良好的抗菌性能。     

壳聚糖、纳米壳聚糖对聚乙烯醇膜结构与性能的影响

研究添加同一质量分数壳聚糖(chitosan,CS)、纳米壳聚糖(chitosan nanoparticles,NCS)改性聚乙烯醇(polyvinyl alcohol,PVA)膜的性能,利用色差仪与紫外分光光度计探究其光学性能;利用透气性测试仪与透湿性测试仪测试共混膜透气性能与透湿性能;通过等温吸湿实验研究了PVA膜、PVA/CS共混膜、PVA/NCS共混膜的吸湿性能,并将常见的等温吸湿曲线模型与实验数据进行拟合;采用傅里叶变换红外光谱(Fourier transform infrared spectrometer,FT-IR)、差示扫描量热(differential scanning calorimetry,DSC)仪对3种膜的结构与结晶度进行表征。结果表明:CS的加入会使PVA膜对中波紫外线的屏蔽作用增强,NCS的加入会使屏蔽效果更加明显;CS或NCS的加入会使PVA透气性能减弱,透湿性能增强;3种共混膜的等温吸湿曲线与GAB方程的拟合效果最好(R~20.98);FT-IR结果表明,PVA/CS、PVA/NCS共混均匀且共混材料之间形成分子间氢键;DSC结果表明,加入CS或NCS之后PVA分子的结晶速率变慢,结晶度下降,分子结晶的吸热焓值增加。     

溶菌酶/壳聚糖/聚乙烯醇纳米纤维膜的制备及表征

本研究采用静电纺丝技术制备不同质量比的壳聚糖/聚乙烯醇纳米纤维膜(CS/PVA),通过SEM分析纤维形貌差异。选择纤维形貌较好的CS/PVA(质量比为1/9)纳米纤维膜,添加不同含量溶菌酶制备溶菌酶/壳聚糖/聚乙烯醇系列纳米纤维膜(LZ/CS/PVA)。采用SEM、FTIR、XRD及DSC等方法分析LZ/CS/PVA纤维膜形貌特点和纤维膜的特性。结果表明:LZ的添加影响了纤维形貌均匀程度及纤维之间的黏结程度;随着溶菌酶的加入,纤维平均直径从339.62±92.72nm(CS/PVA)降低至262.10±86.32～283.01±96.83 nm(LZ/CS/PVA系列纤维)之间;LZ添加量为0.30%和0.50%时,纤维形貌良好;纤维膜各组分之间存在强烈的相互作用,阻碍晶体的形成,导致几乎无定形的结构;LZ的添加提高了纤维膜的热稳定性,熔点从185.60℃上升到189.30℃～191.00℃之间。LZ/CS/PVA纤维膜由安全无毒的材料制备而成,具有应用于食品工业的潜力。     

壳聚糖/PVA共混纤维及改性研究进展

壳聚糖纤维存在纺丝过程连续性不好,力学性能差等缺点,影响其使用性能。而通过PVA和壳聚糖共混制备纤维的方法,对壳聚糖纤维的改性是可行且比较有效的改性方式。文章介绍了近年来关于壳聚糖/PVA共混纤维及改性方面的研究和进展。壳聚糖/PVA共混纤维的成型方式主要有湿法纺丝和静电纺丝两种,对两种不同方法制备的壳聚糖/PVA共混纤维的性质及共混纤维的改性研究进行了综述。壳聚糖/PVA共混纤维的应用主要体现在对金属离子的吸附和在生物医学方面,最后对壳聚糖/PVA共混纤维在未来的应用提出展望。     

壳聚糖纺丝液性能对静电纺纤维形态的影响

配置壳聚糖(CS)与聚乙烯醇(PVA)质量比为0 ∶ 100、10 ∶ 90、20 ∶ 80、30 ∶ 70的纺丝液,并通过静电纺丝工艺制得CS/PVA纳米纤维膜.探讨纺丝液的黏度、电导率、表面张力对CS/PVA纳米纤维膜表观形貌的影响.结果表明:随着CS含量的增大,CS/PVA纺丝液黏度提高、电导率上升、表面张力下降...     

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