6种国产膜在苹果汁加工中的应用比较

以小国光苹果为原料 ,采用聚砜 (PS)、磺化聚砜 (SPS)、聚砜 磺化聚砜共混膜 (PS SPS)、聚丙烯腈 (PAN)、羧基化改性的PAN板式膜、中空纤维PAN膜等 6种国产膜材料对苹果汁进行超滤澄清处理 ,比较了 6种国产膜在苹果汁澄清超滤中通量的变化、不同清洗方式对膜通量的恢复情况和不同膜材料对苹果汁理化指标和感官指标的影响。结果发现 ,6种国产膜均适合对苹果汁进行超滤澄清 ,其中PS SPS混膜在苹果汁的超滤工艺中具有更好的应用前景 ;PS SPS共混膜和改性PAN膜具有较高的抗污染能力。另外 ,采用 0 .1 %酶清洗(NOVOFERM5 8)与 0 .5 %碱液 (pH 1 2 )结合的方式 ,能显著性地提高膜清洗后的通量。     

聚丙烯腈基中空碳纤维膜制备及结构研究

研究了在不同工艺条件下制备的聚丙烯腈(PAN)基中空碳纤维膜和预氧化膜及其结构特征。通过实验得出,基膜的拉伸使预氧化膜和碳化膜致密化,在制备PAN基膜时加入聚甲基丙烯酸甲酯(PMMA)和聚酰亚胺YJ-16添加剂,有助于保持中空纤维膜的指状孔结构,得到孔结构较好的预氧化中空纤维膜和中空碳纤维膜。     

聚丙烯腈/羧基丁苯乳胶复合纳米纤维膜的制备及其性能

为提高静电纺聚丙烯腈(PAN)纳米纤维膜的力学性能,将羧基丁苯乳胶(SBR)与PAN纳米纤维膜通过溶液浸泡进行复合,制备了一系列PAN/SBR复合纳米纤维膜,研究了SBR质量分数对PAN纳米纤维膜表面形貌、化学结构、润湿性能、热性能和力学性能的影响.结果表明:SBR以物理粘结的形式与PAN纳米纤维膜复合在一起,随着SB...     

改性聚丙烯腈纤维与金属离子的配位反应及其应用进展

为解决聚丙烯腈（PAN）纤维在产业用纺织品应用中存在的问题,介绍了腈基通过多种化学反应在PAN纤维表面引入偕胺肟基、胺基、羧基以及其他配位基团的改性方法,比较了不同改性PAN 纤维与过渡金属离子或稀土金属离子的配位反应模式及其所生成配合物的分子结构和特性,评述了多种改性PAN纤维在重金属离子去除、微量金属离子检测、稀有金属和贵金属离子浓缩富集以及绿色催化剂制备等领域中的应用进展,最后指出引入新型配位基团、纤维材料重复利用性的提高和纳米纤维膜的应用是目前促进PAN纤维在产业用纺织品中发展的主要方向。     

偕胺肟化SiO2/聚丙烯腈复合纤维膜的制备及其性能

为构筑具有特殊表/界面性能的膜材料,利用静电纺丝技术制备SiO₂/聚丙烯腈(PAN)复合纤维膜,然后经盐酸羟胺偕胺肟化处理赋予其超亲水及水下超疏油性能。借助场发射扫描电子显微镜、X射线能谱仪、傅里叶变换光谱仪及接触角测试仪等分析了纤维膜的微观形貌、结构和表/界面性质。结果表明:偕胺肟化改性后纤维膜表面有絮状物包覆,盐酸羟胺改性液最佳质量浓度为35~40 g/L,最佳改性温度为60 ℃,偕胺肟化SiO₂/PAN纤维的平均直径为275 nm;改性后纤维膜表面Si和O元素质量分数为2.13%和6.60%,SiO₂锚固在PAN纤维膜表面,且SiO₂/PAN偕胺肟化成功;相比PAN纤维膜,SiO₂/PAN纤维膜在60 ℃偕胺肟化后水润湿时间由5.4 s缩短到0.5 s,且水下油接触角达到(165.2±1)°;偕胺肟化纤维膜断裂强度达4.1 MPa,可满足油水分离的基本要求。     

聚醚砜中空纤维膜的制备及其性能

聚醚砜（PES）中空纤维膜已被广泛使用在许多领域,如超滤,微滤,反渗透,液体/液体或液体/固体分离,气体分离,血液透析等。本文制备了聚醚砜中空纤维膜,并研究了膜的结构和性能。通过研究的成分和工艺条件对聚醚砜中空纤维膜的形态和性能的影响,从而掌握膜的结构和性能的关系。采用了浸入沉淀相转化法,通过改变聚合物溶液浓度,空气浴时间,凝固浴组成等参数来调节膜的性能。运用孔隙率、纯水通量和扫描电子显微镜（SEM）对膜的形态和性能进行表征。研究表明,膜的形态受到聚合物溶液浓度、凝固浴组成等工艺参数的较大影响,通过工艺条件的组合,制得具有良好的性能和理想结构的中空纤维膜。     

中空纤维膜分离酵母提取液中活性成分的初步研究

以啤酒废酵母为原料,研究了中空纤维膜(微滤和超滤)分离酵母提取液中活性成分的工艺.基于超滤机理分析了操作压力、温度、pH值和料液浓度对膜通量的影响,得到超滤工艺最佳条件:压力为0.105MPa,温度、pH值和料液浓度分别为24℃、6.0、3.0%.在此条件下,膜通量为18.42 L/m2·h,海藻糖透过率为96.36%,蛋白质截留率为94.50%.经高效液相色谱(HPLC)验证,实现了酵母提取液中活性成分的分离.     

聚丙烯腈纤维差别化及其在环境净化中的应用进展

为拓展聚丙烯腈(PAN)纤维在产业用纺织品中的应用广度和深度,介绍了通过物理改性、化学改性、截面异形化以及纳米化等对PAN纤维进行差别化处理的方法,改性后的PAN纤维通过材料的结构特征或引入的功能基团以吸附、氧化还原、截留等方式去除水体、空气以及土壤中的有害物质。评述了差别化PAN纤维在海水淡化、油水分离、有机污染物去除等水体净化领域,颗粒和有害气体过滤、气液分离等空气净化以及土壤净化3大环境领域方面的应用进展,并指出PAN纤维的绿色生产和废旧PAN纤维的绿色差别化是未来促进差别化PAN纤维在产业用纺织品中发展的主要方向。     

聚丙烯腈纳米纤维氨基化改性及重金属吸附性能

将聚丙烯腈(PAN)溶于N,N-二甲基甲酰胺(DMF)中,采用静电纺丝技术纺制PAN纳米纤维,用戊二醛和超支化聚合物(HBP)对纤维进行氨基化改性,分析了戊二醛和HBP用量,以及反应时间和温度对氨基化改性的影响,通过扫描电镜和红外光谱观察PAN纳米纤维改性前后的形态及微观结构变化,测试了PAN纳米纤维对重金属的吸附效果。结果表明,改性后的PAN纳米纤维对重金属的吸附量是未改性纤维的21倍。     

果汁超滤机的研究

介绍了果汁超滤机的机械设计及自动控制的实现，对影响中空纤维膜渗透速率的两个主要因素操作压力和主流液循环流量做正交试验确定了二者最佳组合，对超滤后的果汁进行测定分析，并对中空纤维膜的清洗恢复方法迸行了探讨。     

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.     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.