两性壳聚糖的制备及其纸张增强性能研究

以CTS-ETA进行羧甲基化改性,制得两性壳聚糖,制备羧甲基化CTS—ETA的优化条件为：CTS-ETA／氯乙酸（质量比）=1．5：1,碱化时间为1n,醚化时间为5h,醚化温度为60℃,并将自制改性壳聚糖应用于纸张的增强。试验结果表明：两性壳聚糖可用作纸张的增强剂,加入少量（0．2％～0．3％）就能显著提高纸张的物理强度。     

荸荠渣羧甲基化产品的研制

研究了以荸荠渣(C6H9O4OH)为原料,采用甲醇溶剂法,在碱性条件下制备出荸荠渣羧甲基化产品(WCDCMCS)。对制备工艺中的最佳黏度条件进行了探讨,结果表明:当n(荸荠渣)∶n(甲醇)=1∶16、碱化时间定为0.75h时,采用最佳黏度工艺条件,即n(荸荠渣)∶n(氢氧化钠)∶n(氯乙酸)=1∶2∶1、碱化温度为40℃、醚化温度为45℃、醚化时间为2h,可以制备黏度高达840mPa·s的荸荠渣羧甲基化产品。     

应用于纸张增强的羧甲基化壳聚糖的合成研究

羧甲基化壳聚糖是制浆造纸行业中应用十分广泛的造纸化学助剂。随着中国造纸行业的迅速发展,其应用领域也不断拓展。羧甲基化壳聚糖可用于纸张增强,它既可增加纸张的干强度,也可以提高纸张的湿强度。研究了羧甲基化壳聚糖的合成并将其用于纸张增强,研究了不同因素对取代度的影响,对产物进行了红外光谱的表征,并将产物用于纸张的增强实验以验证效果。     

交联羧甲基复合变性淀粉合成研究

以玉米淀粉为原料,环氧氯丙烷为交联剂、氯乙酸为羧甲基化试剂,在碱催化条件下合成交联羧甲基复合变性淀粉。通过工艺条件优化及结果分析,筛选出较佳合成条件为:交联剂用量为淀粉量的0.1%,m(淀粉)∶m(氯乙酸)∶m(氢氧化钠)=1∶0.47∶0.35,醚化时间为3 h,醚化温度45℃。获得了取代度在0.4左右,黏度可高于15 000 mPa·s(4%水溶液)的交联羧甲基复合变性淀粉。     

羧甲基壳聚糖作为纸张增强剂研究

该文主要研究用壳聚糖和一氯乙酸制备羧甲基壳聚糖,详细考察了碱的用量、碱化时间、醚化剂的用量、醚化温度等条件对羧甲基化反应及羧甲基壳聚糖性质的影响;并且通过应用实验表明当其加入量为0.10%时,羧甲基壳聚糖就显示出良好的增强效果,是一种很好的纸张增强剂.     

纸张增强用羧甲基化壳聚糖的应用研究

本研究通过比较不同抄造条件下,如羧甲基化壳聚糖的用量,不同取代度的羧甲基化壳聚糖,以及对于不同浆料等变量条件下所抄造的纸张来考察对强度的影响。研究表明,对于漂白针叶木浆,当羧甲基壳聚糖的取代度为1．02附近时,纸张的裂断长达到最大,纸张的撕裂指数、耐破指数和耐折度都有不同程度的增加,对于苇浆基本上趋于一致。而随着羧甲基化壳聚糖的用量的增加,无论是是针叶浆还是苇浆,纸张强度较空白样都有提高。     

玉米秸穰亲水改性研究

以玉米秸穰材料为原料,利用硝酸乙醇法对秸穰处理前后纤维素含量进行测定,处理后原料中的葡聚糖质量分数可达81%。通过对秸穰材料各组分含量的分析,可知,在玉米秸穰中,综纤维素含量接近60%。进行了碱化和醚化反应的工艺参数的探讨,分析了用碱量,碱化时间和温度,二次加碱法的两次加碱比例,醚化反应一氯乙酸用量,交联反应交联剂用量等因素对产品性能的影响,选择最佳的工艺条件为m(NaOH)∶m(秸穰材料)∶m(一氯乙酸)=1∶1.2∶2.4,以异丙醇为分散剂两次加碱质量比为2∶1,T(碱化)=30℃,t(碱化)=80min,T(醚化)=65℃,t(醚化)=120min,交联反应环氧氯丙烷用量为羧甲基化秸穰质量的12%,得到羧甲基化产品取代度为1.30,最终材料的吸水倍率为50g/g。     

羧甲基淀粉的干法制备及特性研究

采用现代环保干法工艺以取代度为指标,通过二次通用旋转组合试验设计,对玉米淀粉进行羧甲基醚化改性处理研究,得出回归模型.结果表明,羧甲基化改性的最佳工艺条件为醚化温度为74.44℃,NaOH/淀粉的物质的量比值为1.85,醚化时间2.33 h,乙醇浓度为84.65%,羧甲基化改性淀粉取代度为0.49,反应效率为81.7%.并利用布拉班德黏度仪、生物显微镜以及红外光谱仪对改性淀粉进行表征.为实现大规模工业化生产提供理论依据和实际参考.     

季铵化壳聚糖改性棉织物活性无盐染色

用季铵化试剂3-氯-2-羟丙基三甲基氯化铵(CTA)对壳聚糖(CTS)进行改性,制备了季铵盐壳聚糖类衍生物2-羟丙基三甲基氯化铵-壳聚糖(CTA-CTS)。优化的改性工艺为:反应时间10 h,反应温度65℃,反应物质量比为:m(氢氧化钠)∶m(壳聚糖)=1∶1,m(CTA)∶m(壳聚糖)=3∶1。CTA-CTS应用于棉织物表面改性,不仅可以实现无盐染色,而且还能在不降低色牢度的情况下改善染色效果。     

壳聚糖衍生物膜性能对水果保鲜作用的影响

目前国内应用的保鲜膜主要有PVC、PE两种,不仅保鲜效果不佳,且或多或少危害人体健康。改性壳聚糖具有优异的成膜性、抗菌性、吸湿性,无毒,易降解,因此改性壳聚糖保鲜果蔬已引起越来越多国家研究机构的重视。首先制备壳聚糖(CTS)、壳聚糖/二甲基二烯丙基氯化铵(CTS-DMDAAC)、羧甲基壳聚糖(CMCTS)、壳聚糖/2,3-环氧丙基三甲基氯化铵(CTS-ETA)保鲜膜,对改性壳聚糖膜进行抗拉强度、吸湿性、水溶性的测试,然后对改性壳聚糖膜应用于保鲜杨梅进行了研究。结果表明:膜的抗拉强度由大到小的顺序为CTS>CTS-DMDAAC>CMCTS>CTS-ETA,CMCTS膜的吸湿性、水溶性最好。制膜法保鲜效果接近涂膜法。改性壳聚糖类保鲜杨梅的最佳浓度为1.5%CTS、1.5%CMCTS、0.2%CTS-DMDAAC、1%CTS-ETA;CTS-ETA保鲜效果最好,CTS保鲜效果最差。低温贮藏效果明显高于常温贮藏。     

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