聚丙烯酰胺/普鲁兰多糖半互穿网络水凝胶制备和性能研究

采用水溶液聚合法制备不同比例的聚丙烯酰胺/普鲁兰多糖半互穿网络水凝胶,研究水凝胶在去离子水、生理盐水中的溶胀行为和其机械性能。结果表明:随着普鲁兰多糖用量的增加,聚丙烯酰胺/普鲁兰多糖水凝胶在去离子水和生理盐水中的溶胀均呈现先增加后降低的趋势。当水凝胶中丙烯酰胺/普鲁兰多糖为10∶4时,去离子水中的溶胀倍率达到最高(16.7 g/g);当水凝胶中丙烯酰胺/普鲁兰多糖为10∶3时,生理盐水中的溶胀倍率达到最高(15.5 g/g)。丙烯酰胺/普鲁兰多糖水凝胶的最大压缩载荷随着普鲁兰多糖含量的增加而呈现先增大再降低,然后再升高的趋势。当丙烯酰胺/普鲁兰多糖达到10:4时,水凝胶的最大压缩载荷达到最大(1099 N)。     

基于甜菜碱的两性离子导电水凝胶的合成及性能北大核心

采用自由基聚合法,以两性离子甲基丙烯酰乙基磺基甜菜碱(SBMA)和非离子型丙烯酰胺(AAm)为单体,N,N-亚甲基双丙烯酰胺(MBAA)为交联剂,过硫酸钾(KPS)为引发剂,成功制备了两性离子导电水凝胶。研究表明:制备的导电水凝胶具有一定的溶胀性能(平衡溶胀率为4.39)和力学强度(拉伸强度为0.045 MPa);由于阴阳离子的存在,网络中的静电相互作用和氢键有利于离子迁移,使其具有优异的导电性能(电导率为0.69 S/cm);随着体系中AAm含量的增加,凝胶的力学性能不断增加,电导率不断减小,溶胀性能呈现先增加后减小的趋势。     

木质素/PAM黏附水凝胶传感材料的制备与性能研究

本研究以木质素和丙烯酰胺为原料,制备了具有一定机械性能及黏附性的木质素/聚丙烯酰胺复合水凝胶.结果表明,添加木质素有利于提高复合水凝胶的力学性能及黏附性能.在木质素含量1％时,复合水凝胶的拉伸应变525％,拉伸应力50kPa,韧性11.2MJ/m3,压缩应变88.7％,压缩应力97kPa,且木质素的加入使复合水凝胶的黏...     

聚乙烯醇/羊毛角蛋白复合水凝胶的制备与表征北大核心

以聚乙烯醇(PVA)和角蛋白(KE)为原料,制备出在网络孔隙结构、力学性能修复方面具有差异性的复合水凝胶,并进行红外光谱、扫描电镜与力学性能的表征与分析。结果表明:聚乙烯醇和角蛋白的不同质量比对网络孔隙结构具有调控作用,水凝胶中孔隙尺寸随KE含量的增加而增大。当PVA与KE质量比为9∶1时,其溶胀率达到42%,断裂强度和断裂伸长率分别达到8.28 MPa和163.2%。水凝胶表现出良好的力学修复和自愈合性能,水凝胶网络在循环拉伸中会产生结构改变,但能够自修复,为其力学应用提供了良好的弹性和耐久性保障。     

高G型海藻酸钠-明胶pH敏感型复合水凝胶的制备与性质

以碳酸钙和葡萄糖酸内酯为缓释钙源,采用共混法制备高G型海藻酸钠-明胶(HGAGNa-GT)复合水凝胶,研究不同复配比例对高G型海藻酸钠-明胶复合水凝胶性质的影响。研究结果表明,在复合水凝胶中,高G型海藻酸钠与明胶之间存在强烈的相互作用和良好的相容性。随着复合水凝胶中明胶所占比例的增加,其凝胶弹性逐渐增大,凝胶硬度呈先增大后减小的趋势。水凝胶的储能模量和损耗模量均随明胶所占比例的增加呈先升高后降低的趋势。水凝胶的凝胶时间随温度的降低逐渐缩短,随明胶所占比例的增加逐渐延长。高G型海藻酸钠-明胶复合水凝胶微球具有良好的pH敏感性,在模拟小肠液和结肠液中的溶胀度较高,并最终于模拟结肠液环境下降解。当海藻酸钠与明胶的复配比例为5∶3时,水凝胶的凝胶网络结构最为牢固,此时的水凝胶在模拟小肠液和结肠液中的溶胀率最高,分别为26.31%和34.25%。     

明胶改善海藻酸钠水凝胶膜的物理性能研究

本研究旨在解决Ca²⁺交联海藻酸钠水凝胶膜极易脱水收缩，三维网络结构单一及热机械性能较差等问题，具体是以海藻酸钠和明胶为成膜基材，以碳酸钙和葡糖酸内酯为交联剂，通过流延法制备水凝胶膜，探究明胶/海藻酸钠的不同比例(0:6、1:6、2:6、3:6、4:6、5:6)对水凝胶膜物理性能的影响。本实验利用傅里叶变换红外光谱对水凝胶膜分子间作用力进行分析，并通过微观结构、溶胀率、凝胶含量、水接触角、机械性能和热性能等指标对水凝胶膜物理性能进行表征。结果表明：明胶和海藻酸钠之间的作用力主要为氢键和聚电解质相互作用，明胶的引入有效改善了单一海藻酸钠水凝胶膜的三维网络结构，提高了水凝胶膜的凝胶含量和疏水性，增强了水凝胶膜的机械性能和热性能，但明胶/海藻酸钠的比例过大也会造成明胶与海藻酸钠相容性和机械性能的下降。综上，当明胶/海藻酸钠的比例为3:6时，水凝胶膜的拉伸强度(29.6 MPa)、弹性模量(164.99 MPa)、凝胶含量(38.91%)和溶胀率(2942.50%)最高，此时水凝胶膜的物理性能最佳，在诸多领域具有潜在的应用价值。     

Fe3+对大豆种皮果胶类多糖凝胶球凝胶特性的影响

通过质构分析和热重分析等方法,探讨FeCl3浓度和大豆种皮果胶类多糖（soy hull pectic polysaccharide,SHPP）质量浓度对其所形成凝胶球的凝胶强度、溶胀性及水分解吸行为的影响。结果表明：适宜的FeCl3浓度和较高的SHPP质量浓度有利于凝胶体系形成凝胶强度大、溶胀率大、网状结构致密的凝胶球。其中,0.3 mol/L FeCl3与6.0 g/100 mL SHPP所形成凝胶球的强度和溶胀率均最大,分别为116.33 g、366%;在实验条件下,0.3 mol/L FeCl3与6.0 g/100 mL SHPP形成的凝胶球进行水分解吸时,指前因子和活化能均最大,表明其凝胶网状结构较致密。     

壳聚糖／果胶水凝胶的制备及其在药物控制释放中的应用

以戊二醛（GA）为交联剂制备了一系列壳聚糖／果胶（CS-PT）pH值敏感水凝胶。研究了合成条件对CS-PT水凝胶溶胀性能的影响。试验结果表明,交联剂含量、pH值、离子强度对水凝胶溶胀率的影响较大,且在酸性条件下的水凝胶的溶胀率远大于碱性条件下的溶胀率,包埋在此水凝胶中的牛血清蛋白（BSA）释放随载药介质的pH值的变化而显著不同,pH值1．0条件下载药的水凝胶释药率大于pH值7．4和9．18条件下的释药率。     

米谷蛋白-小麦阿拉伯木聚糖复合水凝胶性能研究

目的 研究不同米谷蛋白与阿拉伯木聚糖浓度对复合凝胶性质的影响。方法 本研究采用米谷蛋白与小麦阿拉伯木聚糖作为主材料,通过热处理与漆酶诱导复合处理使得米谷蛋白中的酪氨酸与小麦阿拉伯木聚糖链上的阿魏酸共价交联形成复合水凝胶。比较不同浓度米谷蛋白及阿拉伯木聚糖对复合水凝胶的硬度、流变、持水性及溶胀特性的影响。结果 随米谷蛋白及阿拉伯木聚糖浓度分别升高,其复合水凝胶的凝胶硬度、流变特性、持水能力及溶胀特性均显著提高。但可能因凝胶网络结构及作用力等原因,二者浓度达到一定限度(160 mg/ml、25 mg/ml)后,其持水与溶胀特性略有降低。结论 高浓度材料制备所得米谷蛋白/阿拉伯木聚糖复合水凝胶具有较高的力学性能与保水性能,这也为该水凝胶在食品领域进一步研究提供了一定的理论基础。     

改性竹笋纤维水凝胶的制备与表征及其对亚甲基蓝吸附性能研究

以竹笋下脚料为原料提取纤维素并进行改性后,添加κ-卡拉胶并在环氧氯丙烷交联下通过反相悬浮聚合法,成功制备出pH敏感型竹笋复合水凝胶,并使用FT-IR、热重分析、扫描电镜对该复合水凝胶进行表征,研究水凝胶的溶胀性能与动力学,并以亚甲基蓝为模型药物分子,研究不同初始浓度和初始pH对水凝胶吸附性能影响。实验发现:改性竹笋纤维素与κ-卡拉胶发生化学交联,形成具有固定分解温度的三维网状结构水凝胶。该复合水凝胶由于其带负电荷侧链基团在不同pH溶液中静电斥力的差异不同使得其溶胀行为具有pH敏感性,在溶胀初始阶段服从Fickian扩散,在整个阶段符合Schott模型。复合水凝胶具有多孔性能和溶胀性能,使其具有较强吸附性能,吸附实验发现该复合水凝胶对模型药物亚甲基蓝吸附性能良好,该复合水凝胶在药物吸附与缓释领域具有潜在应用价值。     

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.