相溶解度法研究环糊精对纳他霉素的包合作用

目的:研究β-环糊精(β-CD)和羟丙基β-环糊精(HP-β-CD)对纳他霉素的增溶作用。方法:采用紫外分光光度测定纳他霉素含量,相溶解度法研究β-环糊精(β-CD)和羟丙基β-环糊精(HP-β-CD)对纳他霉素的包合作用、增溶作用及包合过程中热力学参数变化。结果:纳他霉素的溶解度随着β-环糊精浓度的增加而呈线性增加,相溶解度图呈AL型;纳他霉素的溶解度与羟丙基β-环糊精浓度在一定范围内呈线性,但随着羟丙基β-环糊精浓度的增加呈负向偏离型,相溶解度图呈AN型。纳他霉素与2种环糊精在包合过程中的吉布斯自由能变化(ΔG)、焓变(ΔH)均为负值,纳他霉素与β-CD在包合过程中的熵变(ΔS)为负值,而与HP-β-CD包合过程中的熵变(ΔS)为正值。结论:纳他霉素与2种环糊精增溶作用明显。     

槲皮素与6-O-α-D-麦芽糖-β-环糊精包合物的理化表征

采用相溶解度法研究6-O-α-D-麦芽糖-β-环糊精(6-O-α-D-maltosyl-β-cyclodextrin,Mal-β-CD)和β-环糊精(β-cyclodextrin,β-CD)对槲皮素的包合效果,利用溶剂法制备Mal-β-CD与槲皮素的包合物,借助紫外光谱分析、红外光谱分析、扫描电子显微镜、X射线衍射、热重及差示扫描量热联用等分析手段研究该包合物的理化性质,并采用分子对接法建立了该包合物的超分子结构。结果表明:Mal-β-CD包合槲皮素的能力高于母体β-CD。分子对接结果表明,槲皮素是沿Mal-β-CD的大口端方向进入其疏水空腔形成包合物,二者间是通过氢键相连接的。较之母体β-CD,Mal-β-CD与槲皮素的包合效果更好,且包合后槲皮素的物相发生重大变化,热稳定性提高。     

富马酸与三种环糊精在水溶液中包合作用的研究

本实验分别探讨了α-环糊精、β-环糊精、羟丙基-β-环糊精在水溶液中对富马酸的包合作用.实验采用紫外吸收光谱法和相溶解度法研究三种环糊精在水溶液中对富马酸的包合和增溶作用,以及包合过程中热力学参数的变化情况.结果表明,富马酸与三种环糊精在水溶液中均可自发形成了1:1(物质的量比)可溶性包合物,从而增加了其溶解度.同时,富马酸与三种环糊精在包合过程中的吉布斯自由能变化(△G)、焓变(△H)和熵变(△S)均为负值,所有过程均为焓驱动过程,且为放热过程(△H＜0)和熵减过程(△S＜0).     

相溶解度法研究环糊精对二氢黄酮苷的增溶作用

采用相溶解度法,在不同温度下测定二氢黄酮苷在不同浓度的β-环糊精、α-环糊精、γ-环糊精、甲基-β-环糊精、羟乙基-β-环糊精、2-羟丙基-β-环糊精、麦芽糖基-β-环糊精溶液中的溶解度,绘制相溶解度曲线,研究环糊精对二氢黄酮苷的增溶作用及包合过程中的热力学参数变化。结果表明,随着环糊精浓度的增加,二氢黄酮苷的溶解度随之增大,相溶解度曲线为AL型,说明二氢黄酮苷与环糊精1∶1包合。7种环糊精均对二氢黄酮苷有增溶作用,增溶顺序为甲基-β-环糊精羟乙基-β-环糊精 2-羟丙基-β-环糊精β-环糊精麦芽糖基-β-环糊精γ-环糊精α-环糊精。     

相溶解度法研究环糊精对山奈酚的增溶作用

采用相溶解度法,在不同温度下测定山奈酚在不同浓度的α-环糊精、β-环糊精、γ-环糊精、甲基-β-环糊精、磺丁基-β-环糊精、羟乙基-β-环糊精、2-羟丙基-β-环糊精、麦芽糖基-β-环糊精溶液中的溶解度,绘制相溶解度曲线,研究环糊精对山奈酚的增溶作用及包合过程中的热力学参数变化规律。结果表明,山奈酚溶解度随着环糊精浓度的增加而呈线性递增的趋势,相溶解度曲线为AL型,环糊精与山奈酚按1∶1包合,增溶效应顺序为磺丁基-β-环糊精羟乙基-β-环糊精甲基-β-环糊精2-羟丙基-β-环糊精γ-环糊精β-环糊精麦芽糖基-β-环糊精α-环糊精,其中α-环糊精的增溶效应较小,磺丁基-β-环糊精的增溶效应突出。     

根皮苷与麦芽糖基-β-环糊精复合物的理化性质研究

根皮苷具有降血糖、抗肿瘤等多种生物活性功能,但其水溶性低、热稳定性差的缺点限制了它在食品工业中的广泛应用。6-O-α-D-麦芽糖-β-环糊精(G2-β-CD)是一种具有高安全性和水溶性的新型β-环糊精衍生物,关于其复合物的研究国内外鲜见报道。本研究利用相溶解度法考察了G2-β-CD包合根皮苷的效果,采用冻干法制备了根皮苷与G2-β-CD的复合物,借助紫外(UV)、红外(IR)、扫描电镜(SEM)、X-射线衍射(XRD)、热重及差示扫描量热联用(TG/DSC)等波谱分析手段对该复合物的理化性质进行了研究,并采用分子对接法建立了该复合物的三维超分子结构。结果表明由于G2-β-CD上麦芽糖基的空间位阻效应,其包合根皮苷的效果低于β-CD。根皮苷与G2-β-CD复合后,其物相发生了重大改变,且水溶性和热稳定性显著提高。分子对接分析表明根皮苷沿G2-β-CD的大口端方向进入其空腔形成复合物,该超分子结构可能通过氢键维持。     

β-环糊精的匀染作用研究

将新型匀染剂β-环糊精用于腈纶的染色中.通过紫外可见分光光度分析,测算β-环糊精与染料的包合常数,探讨其对染料紫外可见光谱的影响;根据染料结构特点,研究了β-环糊精对匀染性能的影响.试验结果表明,匀染剂β-环糊精适用于分子结构大小与之匹配的染料,宜在染色时加入,具有明显的匀染效果.     

白藜芦醇苷与环糊精在水溶液中包合作用的研究

分别研究了β-环糊精(β-CD)、羟丙基-β-环糊精(HP-β-CD)在水溶液中对白藜芦醇苷(PD)的包合作用。采用等摩尔系列法测定包合物的包合比,紫外吸收分光光度法、相溶解度法研究2种环糊精(CDS)在水溶液中对PD的包合作用、增溶作用及包合过程中的热力学参数变化。在水溶液中,PD与2种CDS均存在明显的相互作用。PD的溶解度随着CDS浓度的增加而成线性增加,相溶解图呈AL-型;PD与2种CDS在包合过程的吉布斯自由能变化(ΔG)、焓变(ΔH)和熵变(ΔS)均为负值。PD与2种CDS在水溶液中可自发形成摩尔比1︰1的可溶性包合物,从而增加其溶解度。同时,所有包合过程均为焓驱动过程,为放热反应(ΔH<0),焓减过程(ΔS<0),且适当降低温度将有利于包合过程的进行。     

苯乙醇香精与β-环糊精包合物的制备工艺研究

采用饱和水溶液法制备苯乙醇香精与β-环糊精包合物,通过正交实验确定出最佳工艺条件,即:苯乙醇香精与β-环糊精的配比为1∶6,包合温度为50℃,包合时间为2.5h;在此条件下苯乙醇香精与β-环糊精的包合率为84.75%。包合物紫外光谱的最大吸收波长和吸光度显示,苯乙醇香精与β-环糊精包合物和两者的混合物以及β-环糊精本身显著不同,验证了环糊精包合了苯乙醇香精分子。     

叶黄素酯/α-环糊精包合研究

目的:研究叶黄素酯与α-环糊精的包合性能。方法:紫外法测定包合行为并计算表观包合常数;研磨法制备包合物;溶解度为指标确定包合比;DTA、DR-FTIR、UV-vis DRS验证包合物;与β-环糊精和混合环糊精的包合作用比较,测定其溶解度、稳定性。结果:叶黄素酯与α-环糊精表观包合常数Ka为127 L/mol;包合比1∶5时溶解度最佳;α-环糊精使叶黄素酯稳定性增强,溶解度提高为叶黄素酯原料的6倍以上。结论:α-环糊精应用于叶黄素酯性能优于β-环糊精和混合环糊精。     

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