木犀草素分子印迹聚合物的制备及吸附性能研究

采用分子印迹技术,以木犀草素作为模板分子,丙烯酰胺和甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,制备木犀草素表面分子印迹聚合物。采用静态吸附法研究影响该聚合物对木犀草素的吸附能力的因素,并对等温吸附过程和吸附机理进行判断。结果表明:该印迹聚合物对木犀草素具有优良的吸附效果,在p H值为7.0,底液浓度为100 mg/L,吸附时间2 h条件下,该聚合物对木犀草素的吸附量为28.32 mg/g;吸附平衡试验说明该等温吸附过程符合Langmuir方程,饱和吸附量为31.983 mg/g,吸附动力学研究表明,该吸附过程符合准二级动力学方程,吸附速率常数为0.045 3 g/(mg·min);选择性试验说明该印迹聚合物对目标物具有优异的选择识别能力。该聚合物能应用于木犀草素的前处理、提取等方面。     

离子交换树脂对冰葡萄汁总酸和总酚的静态吸附动力学研究

该实验研究了D354树脂对冰葡萄汁总酸和总酚的静态吸附动力学模型。结果表明,随吸附温度的升高,D354树脂对冰葡萄 汁总酸和总酚的吸附速率显著提高（P＜0.05）。 在0 ℃、10 ℃和20 ℃条件下,D354树脂对冰葡萄汁总酸的最大吸附量分别为151.69 mg/g、 190.09 mg/g及222.16 mg/g;对冰葡萄汁总酚的最大吸附量分别为3.65 mg/g、4.20 mg/g及4.67 mg/g;D354树脂吸附冰葡萄汁总酸和总 酚的过程符合拟二阶动力学模型（R2＞0.9980）,并确定了D354树脂对冰葡萄汁总酸和总酚的拟二阶动力学方程;利用W-M（Weber- Morris）动力学模型对数据拟合（R2＞0.9300）,结果表明整个静态吸附过程受粒内扩散和液膜扩散共同控制。     

直接浸渍冷冻过程中溶质在对虾中渗透规律的研究

在直接浸渍冻结过程中,溶质渗透是影响直接浸渍冻结应用的主要因素。本文通过建立明胶模型,研究直接浸渍过程中不同溶质的渗透模型及规律,并对对虾中的溶质渗透规律进行探索。研究发现,溶质中的甜菜碱、丙二醇及氯化钠在明胶模型中的渗透深度分别为0.2 cm、0.35 cm及0.4 cm,渗透量分别为4.35±0.12 mg/g、6.15±0.12 mg/g、11.73±0.18 mg/g;在对虾中的渗透深度分别为0.25 cm、0.31 cm、0.35 cm,渗透量分别为0.86±0.07 mg/g、1.53±0.11 mg/g、1.67±0.08 mg/g。通过对直接浸渍冻结过程溶质的变化进行回归分析,溶质的渗透规律可用回归模型进行表达,并且甜菜碱、丙二醇及氯化钠在对虾中的渗透变化趋势与明胶模型相对一致,前5 min内,甜菜碱、丙二醇、氯化钠扩散速率较大,几乎呈直线增加,6 min后,扩散速率减慢。根据所建立的传质模型,甜菜碱、丙二醇、氯化钠在明胶的平均扩散系数分别为4.16×10-7m2/s、1.27×10-6m2/s、1.66×10-6m2/s,在对虾中的平均扩散系数分别为2.34×10-7m2/s、9.36×10-7m2/s、1.36×10-6m2/s。     

沉淀聚合法制备葛根素印迹微球及其固相萃取葛根粉

以葛根素为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂沉淀聚合法制备葛根素印迹聚合物微球。用扫描电镜观察微球形貌,静态吸附法测试聚合物的吸附行为。探讨分子印迹聚合物（molecularly imprinted polymers,MIPs）对葛根粗提液中葛根素的吸附、解吸附及固相萃取效能。结果表明,优化的葛根素MIP3对纯模板的静态吸附量达37.9 mg/g;对粗提液中目标化合物的吸附率为（96.3±1.81）%,以水、甲醇-醋酸（9∶1,V/V）及50%甲醇溶液为洗脱剂的单次解吸率为27%～34%,用水从MIP3上解吸出的总溶液经脱除溶剂后,所获粗品葛根素含量最高,达（37.4±2.87）%。在优化条件下,通过MIP3固相萃取葛根粗提液,葛根素回收率达71.6%,产品纯度高于75%。     

沙拉沙星分子印迹聚合物的制备及其性能研究

以沙拉沙星为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用本体聚合制备沙拉沙星的分子印迹聚合物。通过振荡吸附实验对模板分子和功能单体的比例进行优化。印迹聚合物和空白聚合物的等温吸附线表明,印迹聚合物形成的孔穴对沙拉沙星的吸附量高于空白聚合物。在吸附过程中模板分子沙拉沙星与印迹聚合物形成两种结合位点,两种结合位点的解离常数分别为0.321μg/mL和1.577μg/mL,对沙拉沙星最大表观吸附量分别为1.249mg/g和3.222mg/g。吸附动力学实验结果显示聚合物对沙拉沙星的吸附在7h达到平衡,选择性试验表明印迹聚合物对沙拉沙星具有较好的吸附特性。     

松香基功能高分子稀土离子配合物固定化淀粉酶

分别以聚马来松香己二醇酯、马来松香乙二醇丙烯酯聚合物和马来松香乙二醇丙烯酯- 丙烯酸共聚物为载体,稀土离子为桥键配离子固定化淀粉酶。测定固定化淀粉酶的性能,探讨固定化酶反应机理。结果表明,稀土离子作为桥键配离子的固定化淀粉酶中,PMGAE Y(III)En 和PMGAEDy(III)En 效果较好;最适宜温度均为60℃,最适宜pH 值均为6.03;重复使用4 次后,活性分别为31.49、29.76mg/g·5min。此外,建立了固定化酶活性与功能高分子微孔面积及酸值间的数学关系式。     

孔隙结构和脂肪含量对饼干水分吸附特性的影响

采用动态水分吸附法研究不同孔隙率和脂肪含量的发酵饼干在25℃下的水分吸附动力学特性,基于GAB模型和无限大平板模型确定其等温吸湿曲线和有效水分扩散系数。结果表明:孔隙率对饼干平衡水分含量几乎没有影响,而随着脂肪含量的增加,饼干的平衡水分含量逐渐下降。GAB模型能成功拟合饼干的等温吸湿数据。饼干的有效水分扩散系数随含水量变化先增大而后逐渐减小,有效水分扩散系数在水分含量为10 g/100 g(干基)左右时达到最大值。初始孔隙率87%、76%和68%的最大有效水分扩散系数分别为7.8×10-10m2/s、5.6×10-10和3.4×10-10m2/s,这与水分扩散机理从以气态传输为主向以液态传输为主的转变有关。增加脂肪含量会显著降低水分扩散系数,有效水分扩散系数从最大值5.6×10-10m2/s下降到2.3×10-10m2/s。     

吡蚜酮分子印迹聚合物的制备及吸附性能表征

以吡蚜酮为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,采用本体聚合法制备了吡蚜酮分子印迹聚合物。实验优化了模板分子与功能单体的摩尔比,通过吸附动力学和等温吸附实验对聚合物的吸附性能进行了表征,利用拟二级动力学模型和Scatchard分析研究了聚合物对目标物的吸附行为。实验结果表明:模板分子与功能单体摩尔比为1∶4时,制备的吡蚜酮分子印迹聚合物具有较好的印迹效果,最优条件下聚合物的吸附容量为25.11mg/g,印迹因子为3.0,可在80min内达到吸附平衡(20mg/L);聚合物对目标物的吸附行为符合拟二级动力学模型(R2=0.999),Scatchard分析结果表明聚合物在聚合过程中形成了较为明显的印迹位点,对目标物呈现一致的亲和力。      

氯霉素分子印迹聚合物的制备及性能研究

采用表面分子印迹技术,以氯霉素为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,制备氯霉素表面分子印迹聚合物。通过扫描电镜、等温吸附实验、Scatchard方程分析及吸附动力学实验对氯霉素分子印迹聚合物进行性能表征。结果表明,合成的分子印迹聚合物对氯霉素的最大吸附量为51μg/mg,有较好的特异性吸附,且吸附速率快,2 min即可达到吸附平衡。     

吡蚜酮分子印迹聚合物的制备及吸附性能表征

以吡蚜酮为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,采用本体聚合法制备了吡蚜酮分子印迹聚合物。实验优化了模板分子与功能单体的摩尔比,通过吸附动力学和等温吸附实验对聚合物的吸附性能进行了表征,利用拟二级动力学模型和Scatchard分析研究了聚合物对目标物的吸附行为。实验结果表明:模板分子与功能单体摩尔比为1∶4时,制备的吡蚜酮分子印迹聚合物具有较好的印迹效果,最优条件下聚合物的吸附容量为25.11mg/g,印迹因子为3.0,可在80min内达到吸附平衡(20mg/L);聚合物对目标物的吸附行为符合拟二级动力学模型(R2=0.999),Scatchard分析结果表明聚合物在聚合过程中形成了较为明显的印迹位点,对目标物呈现一致的亲和力。     

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.     

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