硫酸高铈催化合成苹果酯-A的研究

以硫酸高铈为催化剂,通过乙酰乙酸乙酯和乙二醇反应合成了苹果酯,研究了各有关因素对产品收率的影响。实验表明,硫酸高铈是合成苹果酯的良好催化剂,在酯醇物质的量比为1∶1.2,催化剂用量为0.3g/0.1mol乙酰乙酸乙酯,环己烷8mL,反应时间2h的条件下,苹果酯的收率可达93.1%。     

H3PW12O40/C催化合成苹果酯和苹果酯-B

制备了环境友好催化剂活性炭负载磷钨酸H3PW12O40/C,并以负载量为23.1%H3PW12O40/C催化合成了苹果酯、苹果酯-B.合成苹果酯、苹果酯-B的适宜工艺条件为n(醇)n(乙酰乙酸乙酯)=1.51,H3PW12O40/C用量为反应物总质量的1.0%,反应时间分别为90min和120min,苹果酯、苹果酯-B的收率分别为80.4%和84.8%.目的产物经红外光谱、元素分析和质谱确证.     

活性炭负载磷钨酸催化合成香料苹果酯-B

制备了环境友好催化剂活性炭负载磷钨酸H3PW12O40/C，并以H3PW12O40/C为催化剂催化合成了香料苹果酯-B。得到了苹果酯-B合成的适宜工艺条件：n（1，2-丙二醇）：n（乙酰乙酸乙酯）=1．5：1，H3PW12O40/C负载量为23．1％，H3PW12O40/C用量为反应物总质量的1．0％，反应时间为120min，苹果酯-B的收率为84．8％，目的产物经红外光谱、质谱和元素分析确证。     

微波辐照相转移催化合成香料苹果酯

以乙酰乙酸乙酯和乙二醇为原料合成苹果酯。用单因素试验法和正交试验法探讨了催化剂、投料比、反应温度、反应时间和加热方式等因素对苹果酯合成的影响。试验结果表明:在微波辐照下,最佳反应条件为:以硫酸氢钠/三氯化铁为催化剂、PEG-800为相转移催化剂、乙酰乙酸乙酯:乙二醇(mol)为1∶1.5～1.8、甲苯为带水剂、微波功率为中低档、微波辐照时间为8～12min,产率可达91.5%以上。产品经IR、1HNMR、MS和GC等测定,其结果与文献值一致。     

微波辐照相转催化合成香料苹果酯

以乙酰乙酸乙酯和乙二醇为原料合成苹果酯。用单因素试验法和正交试验法探讨了催化剂、投料比、反应温度、反应时间和加热方式等因素对苹果酯合成的影响。试验结果表明：在微波辐照下，最佳反应条件为：以硫酸氢钠／三氯化铁为催化剂、PEG－800为相转移催化剂、乙酰乙酸乙酯：乙二醇（mol）为1：1.5-1.8、甲苯为带水剂、微波功率为中低档、微波辐照时间为8－12min，产率可达91.5%以上。产品经IR、^1HNMR、MS和GC等测定，其结果与文献值一致。     

硫酸高铈催化合成丁酸异丁酯

以硫酸高铈为催化剂,正丁酸和异丁醇为原料合成了丁酸异丁酯.考察了催化剂用量、醇酸物质的量比、反应时间、带水剂种类及催化剂重复使用性等因素对收率的影响.结果表明该催化剂与反应体系形成非均相物系,具有易分离回收,催化活性高,反应时间短,出水速率快,合成工艺流程简单,操作方便,不易腐蚀设备,废液排放量少,不需加带水剂即可获得较为理想的收率等优势,基本革除了浓硫酸为酯化催化剂存在的设备腐蚀严重、后处理工艺复杂、主反应选择性低、废液排放量多等弊端.硫酸高铈是合成丁酸异丁酯的高效、经济且环境友好的酯化催化剂,具有一定的工业化应用前景.适宜反应条件为:正丁酸0.15mol,醇酸物质的量比1.1,催化剂用量1.1g,反应时间90min,收率86.1%.     

硝酸钇绿色催化合成乙酸苄酯的研究

以硝酸钇为催化剂,冰乙酸和苯甲醇为原料合成乙酸苄酯进行了研究。重点考察了催化剂用量、酸醇物质的量比、反应时间、带水剂种类及催化剂重复使用性对乙酸苄酯收率的影响。实验结果表明,硝酸钇对合成乙酸苄酯有着良好的催化活性,当催化剂用量为苯甲醇用量的1.5%(摩尔百分比),乙酸和苯甲醇的摩尔比为1.2∶1.0,环己烷为带水剂,反应时间为2.0h,乙酸苄酯收率可达93.2%,且催化剂重复使用多次后仍保持较高活性。与以浓硫酸为催化剂合成乙酸苄酯的传统工艺所存在设备腐蚀严重、后处理工艺复杂、污染环境等缺点相比,以硝酸钇为催化剂合成乙酸苄酯的工艺具有操作简单,产率较高,对环境友好且催化剂经简单分离可回收并多次重复使用的优点。     

响应面法优化蔗糖多酯的合成工艺

以油酸甲酯和蔗糖为原料,十六烷基三甲基溴化铵为相转移催化剂,采用两步无溶剂法合成蔗糖多酯。以蔗糖多酯收率和酯化度为指标,考察反应时间、反应温度、催化剂用量、反应物摩尔比对蔗糖多酯合成效果的影响,用响应面法对蔗糖多酯的合成工艺条件进行优化。实验结果表明,蔗糖多酯最佳合成条件为:反应时间5.1 h,反应温度139.5℃,催化剂用量2.86%,油酸甲酯与蔗糖的摩尔比10∶1。在最佳条件下,蔗糖多酯收率达到86.20%,酯化度为6.69。     

维生素C催化合成尼泊金高级醇酯

以维生素C为催化剂,对羟基苯甲酸和十六醇及十八醇 为原料合成尼泊金十六酯与尼泊金十八酯。考察了酸醇 摩尔比,催化剂用量,反应时间等对酯收率的影响。在优 化工艺条件下,尼泊金十六酯收率为90.4％,尼泊金十八 酯收率为89 2％。研究结果表明,维生素C具有高的催化 活性。     

丁酸苄酯的催化合成

以硫酸氢钾为催化剂,丁酸和苄醇为原料合成丁酸苄酯。考察了催化剂用量、醇酸物质的量比、带水剂种类、反应时间等因素对收率的影响。该催化剂具有价廉易得,催化活性好,工艺流程简单,操作方便,不腐蚀设备,无环境污染等优点,适宜反应条件下收率可达91.87%。表明硫酸氢钾是合成丁酸苄酯的高效、经济且环境友好的催化剂,具有工业化应用前景。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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