高级脂肪醇类消泡剂主单体的合成及表征

以对甲苯磺酸为催化剂合成了高级脂肪醇类消泡剂主单体硬脂酸单甘油酯．并对其进行了分子蒸馏纯化。通过正交实验、单因素实验探讨了反应时间、反应物摩尔比、催化剂用量和反应温度等基本工艺参数对酯化率的影响。研究表明：当反应时间为3．0h、甘油与硬脂酸摩尔比为1．3：1、催化剂为脂肪酸量的0．3％及反应温度为170℃的优化合成条件下,酯化率可达90％。产物经元素分析和IR表征,确定产物为硬脂酸单甘油酯。     

HClO_4-SiO_2催化合成尼泊金丙酯

以对羟基苯甲酸和正丙醇为原料,HClO4-Si O2为催化剂,经过回流脱水酯化法直接合成对羟基苯甲酸丙酯。催化剂循环使用6次,酯化率可高达90.1%。该反应产率高、反应时间短、操作简单等优点。     

木薯醋酸酯淀粉的制备与表征

用醋酸酐为酯化剂、甲苯-4-磺酸为催化剂在水溶剂体系中,对木薯淀粉进行酯化变性,制得木薯醋酸酯淀粉。通过单因素试验得到制备木薯醋酸酯淀粉的较佳工艺条件为:醋酸酐质量分数15%、催化剂质量分数1.5%、反应时间3h、反应温度45℃、浴比1∶3。傅里叶红外光谱分析证实淀粉酯化变性的发生;扫描电镜显示酯化反应不仅发生在淀粉表面,还发生在淀粉颗粒内部;X射线衍射表明酯化反应破坏淀粉的部分结晶结构,结晶度从37.79%下降到29.76%;差示扫描量热法表明淀粉酯化变性改善其熔融性能,熔融温度较原淀粉下降了22.3℃。     

对甲苯磺酸催化合成季戊四醇异硬脂酸酯工艺优化及其表征分析

为改善现有季戊四醇异硬脂酸酯生产工艺存在的反应时间长、反应温度高、效率低等问题,研究采用对甲苯磺酸催化季戊四醇与异硬脂酸酯化合成季戊四醇异硬脂酸酯。以异硬脂酸酯化率为考察指标,利用单因素实验和正交实验对酯化工艺条件进行优化,对酯化粗产物进行除酸提纯处理,并对粗产物进行红外光谱分析,对除酸提纯产物进行质谱分析、热重分析及性能指标测定。结果表明：最优的酯化反应工艺条件为反应时间5 h、反应温度140℃、催化剂用量1%(基于反应总投料质量)、异硬脂酸与季戊四醇物质的量比值4.3,在此条件下酯化率为99.27%,粗产物酸值(KOH)为13.26 mg/g。红外光谱结果表明此酯化反应合成了季戊四醇异硬脂酸酯,质谱鉴定结果显示主要合成产物为季戊四醇四异硬脂酸酯。经脱酸处理,产物的酸值(KOH)降为3.23 mg/g,与市售产品接近,热重分析及性能指标测定结果显示提纯产物具有优异的热稳定性,良好的黏温性能、优异的低温流动性及良好的安全性。优化的对甲苯磺酸催化合成季戊四醇异硬脂酸酯工艺具有能耗低、产物品质高的优点。     

响应面法优化月桂酸单甘油酯的催化合成工艺

以月桂酸和甘油为原料,采用直接酯化法合成月桂酸单甘油酯,单因素试验考察了催化剂种类与用量、反应时间、反应温度和物料摩尔比对合成产物中月桂酸单甘油酯含量的影响。在此基础上,利用响应面法对合成工艺进行优化,获得响应面优化工艺为:以氧化钙为催化剂,其用量0.21%,反应时间5.4 h,反应温度166℃,甘油与月桂酸的摩尔比1.5︰1,此条件下产物中月桂酸单甘油酯的含量为61.81%。以正己烷为溶剂,在低温下经三次结晶后获得含量为93.64%的纯化产物,红外光谱分析表明,溶剂结晶纯化效果明显。     

大豆多糖固体碱催化剂脱酯效果影响因素

为了研究固体碱催化剂对大豆多糖(SSPS)脱酯效果的影响,以商业高甲氧基大豆多糖(SSPS)为原料,利用固体碱MgO为催化剂,制备低酯化度的SSPS.研究反应温度、时间和催化剂投料质量比对SSPS脱酯效果的影响.脱酯效果通过产物相对分子质量、酯化度(DE)以及产物单糖组成等指标检验.结果显示,随着反应温度升高,产物SS...     

微波辅助植物甾醇油酸酯的酶促催化合成

以candida rugosa脂肪酶为催化剂,采用微波辅助酶法合成植物甾醇油酸酯的研究。通过单因素和正交试验考察反应时间、微波功率、催化剂用量、料液摩尔比4个因素对植物甾醇油酸酯酯化率的影响,优化得出植物甾醇油酸酯的最佳合成工艺条件:反应时间36 min,微波功率550 W,催化剂用量9%,料液摩尔比4∶1。在此工艺条件下合成产物的酯化率为75.26%,经分离纯化后的产物纯度可达到91.19%。气相色谱-质谱及红外光谱检测分析结果表明微波辅助酶法合成产物为甾醇油酸酯。     

Novozym435酶促催化合成共轭亚油酸植物甾醇酯

以脂肪酶Novozym435为催化剂,在有机溶剂中催化合成共轭亚油酸植物甾醇酯.筛选出的最佳溶剂为正丁醇.采用单因素结合正交试验的方法,以甾醇酯化率为考察指标,对反应温度、反应时间、醇油摩尔比以及酶添加量进行了参数优选.结果显示,醇油摩尔比及酶添加量对酯化率影响不显著,反应时间对酯化率有一定影响,反应温度对酯化率的影响极显著.最优条件为:反应温度55℃,醇油摩尔比1:1,酶添加量8%,反应时间48 h.在此条件下,进行了共轭亚油酸植物甾醇酯酶促催化制备,并以气相色谱及红外光谱法对纯化后产物进行了分析确证.     

苯乙酸癸酯的合成及其在卷烟中的应用

以一水合硫酸氢钠作催化剂,苯乙酸和正癸醇为原料合成了苯乙酸癸酯,考察了浓硫酸、对甲苯磺酸、硫酸氢钠作催化剂对酯化率的影响,采用GC/MS、1H NMR、FTIR、折光率和相对密度对合成产物进行了结构表征,并用合成产物进行卷烟加香试验.结果显示:①以硫酸氢钠作催化剂时,反应的酯化率最高;②合成产物为目标物,纯度95.34%;③合成产物可明显提高卷烟烟气的香气质、透发性和劲头.     

食用香料丙酸甘油酯合成研究

运用沉淀—浸渍法制得稀土改性固体超强酸SO2-4/CeO2-Fe3O4-SiO2。以丙酸与甘油合成丙酸甘油酯为探针反应。探讨了酸醇物质的量比、催化剂的用量、反应时间、带水剂的种类及用量等因素对酯化率的影响,并对催化剂的重复使用情况进行了考察。得到最佳反应条件:酸醇摩尔比为3:1,催化剂的用量为反应物料用量的3%,带水剂二甲苯用量为反应物用量的50%,反应时间为3.5 h,此时的酯化率达到97.28%,催化剂重复使用第4次酯化率仍达到80.00%,产品经折光率、FTIR及GC-MS分析知确为目标产物,其纯度为96.83%。     

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