MLM型结构脂的酶法合成及其理化性质分析

以醇解反应制得单甘酯和辛酸为底物,1,3-特异性固定化脂肪酶为催化用酶,在单因素试验的基础上,通过正交试验获得酯化反应制备MLM型结构脂质的最适条件：Lipozyme RM IM酶加入量9%(以底物质量计)、反应时间14h、反应温度40℃、单甘酯与辛酸(底物)物质的量比1:6;该条件下辛酸插入率达60.48%,其中92.84%的辛酸分布在甘油结构的1,3位上。经二级分子蒸馏纯化后得到的MLM型结构脂质,辛酸插入率达到73.34%;对其进行理化指标检测分析表明,该产品最低可达国家四级菜籽油的标准。     

两步酶法合成MLM型结构脂质中醇解反应研究

为获得纯度较高的2-单甘酯来制备MLM型结构脂质,以菜籽油和无水乙醇为底物,用来自Thermomyceslanuginosa固定化脂肪酶TL IM作为催化酶来制备2-单甘酯。在单因素试验的基础上,采用正交试验设计,获得醇解反应的最佳工艺条件:菜籽油/无水乙醇(底物)物质的量比1:5,Lipozyme TL IM酶加入量为7%(以底物质量计)、反应温度35℃、反应时间18h,总单甘酯含量为38.82%。经三级分子蒸馏纯化后,总单甘酯的纯度可以达到90.76%。     

酶催化菜籽油酸解制备结构脂质工艺

以菜籽油和辛酸为原料,用来自Thermomyces lanuginosa固定化脂肪酶TL IM作为催化剂,采用单因素试验结合响应曲面(Box-Behnken设计)优化得到酶法制备结构脂质的工艺条件,最佳制备条件为底物(菜籽油:辛酸)物质的量比1:3.57、加酶量10.57%(以底物质量计)、加水量5.2%(以酶质量计)、反应温度48.6℃、反应时间12h。该条件下辛酸插入率可达23.19%。对提高油菜籽油附加值、延长油菜加工产业链具有重要意义。     

脂肪酶催化玉米胚芽油与辛酸制备MLM型结构脂质

为研究无溶剂系统脂肪酶催化玉米胚芽油与辛酸酸解制备功能性脂质的可能性及反应条件,以玉米胚芽油为原料,比较6种脂肪酶(Lipozyme RM IM、Lipozyme TL IM、Novozym 435、Lipase AK、Lipase AY和Newlase F)对无溶剂体系中固定化脂肪酶催化玉米胚芽油与辛酸酸解制备MLM结构脂质的影响。研究结果表明:所选6种脂肪酶中,来自米黑根毛霉的固定化脂肪酶Lipozyme RM IM的催化效果最好。当玉米胚芽油与辛酸的比率为1∶4(物质的量比)、脂肪酶量为12%(底物质量分数)、反应时间16 h、反应温度50℃时,玉米胚芽油中辛酸插入率最高。在无溶剂系统,利用Lipozyme RM IM脂肪酶催化玉米胚芽油与辛酸进行酸解反应,可制备高品质的MLM型功能性脂质。     

酶法改良大豆油制备质构脂质的研究

研究了固定化脂肪酶催化大豆油与辛酸酸解制备质构脂质的工艺.脂肪酶筛选实验表明,在所选用的三种脂肪酶中,来自Rhizomucor miehei的固定化脂肪酶RM IM催化效果最好.以RM IM为催化剂,进一步考察了酶用量、底物摩尔比、水分添加量、反应温度、反应时间等因素对辛酸插入率的影响.结果表明:当大豆油500mg时,最佳的反应条件为:反应温度40℃,底物摩尔比6∶1(辛酸∶大豆油),固定化酶10%(底物重量百分比),水分添加量10%(酶的重量百分比),反应24h,辛酸的插入率为43%,质构脂质的脂肪酸分布最合理.     

Lipozyme RM IM脂肪酶催化酸解制备MLM型结构脂质

采用脂肪酶Lipozyme RM IM催化辛酸、癸酸与大豆油进行酸解反应以制备MLM型结构脂质。通过单因素实验研究底物摩尔比、辛癸酸摩尔比、酶添加量、反应时间、反应温度和初始水分含量对酸解反应的影响。得到适合的反应条件为:底物摩尔比3∶1(总脂肪酸/大豆油),辛酸与癸酸摩尔比(辛酸/癸酸)2.5∶1,酶添加量7.5 wt%(基于底物总重),反应时间5 h,反应温度65℃,加水量1.0 wt%(基于底物总重),得到MLM结构脂脂肪酸组成中辛酸含量为20.0 wt%,癸酸含量为10.5 wt%,两者质量比为1.92。     

大豆油和月桂酸制备MLM型结构脂质工艺优化及其性质分析

以大豆油和月桂酸作为反应底物,采用Lipozyme RM IM催化合成中长碳链（middle-long-middle,MLM）型结构脂质。通过响应面试验优化方法研究不同底物（月桂酸∶大豆油）物质的量比、反应温度、反应时间、脂肪酶添加量对合成结构脂质中月桂酸插入率的影响,并研究在最佳反应条件下MLM型结构脂质的理化性质。结果表明,最佳合成工艺条件下所得结构脂质的月桂酸插入率为29.26%,该条件为底物物质的量比6∶1、反应温度45?℃、反应时间24?h、脂肪酶添加量为底物质量的13%。理化性质研究表明,与原大豆油相比,MLM型结构脂质碘值（97.38?g/100?g）、黏度（70.39?cP）均降低,皂化值（以KOH计）（229.58?mg/g）、结晶开始温度（4.89?℃）和熔融开始温度（－19.87?℃）均显著提高（P＜0.05）,而烟点（231.24?℃）无显著差异（P＞0.05）。本研究合成的MLM型结构脂质,提高了原大豆油的营养价值,为开发抗肥胖、降血脂的优质油脂提供理论依据。     

MLM型结构脂质特性及氧化稳定性研究

比较研究了菜籽油、菜籽油为底物酶改性制备的含辛酸MLM(中碳链-长碳链-中碳链)型结构脂质的质量指标及其氧化稳定性.含38.1％辛酸的MLM型结构脂质中辛酸96.3％位于甘油sn-1,3位,其游离脂肪酸、皂化值高于菜籽油,氧化稳定性指数(OSI值)、过氧化值(PV)低于原料油脂.添加6种不同抗氧化剂后,结构脂质OSI值有不同幅度的改进,以叔丁基对苯二酚(TBHQ)效果最为显著.添加200 mg/kgTBHQ后MLM型结构脂质的OSI值由5.05 h上升到20.1 h,PV、共轭二烯与硫代巴比妥酸随氧化时间延长而增幅减小.     

菜籽油酶催化改性反应参数及产物性质研究

在非水相酶催化改性菜籽油制备富含辛酸与油酸的结构脂质工艺中,采用Box-behnken设计研究了酶添加量、反应底物比、反应时间、反应温度及其交互作用对辛酸合成率的影响,并分析了产物物化性质.经过回归分析建立了辛酸合成率对反应参数的二次回归模型,回归方程的决定系数为0.994.改性后产物中Sn-1,3位辛酸质量分数为60...     

无溶剂体系中酶催化合成结构脂质条件初探

以菜籽油和辛酸为原料,在无溶剂体系中用脂肪酶催化酸解合成结构脂质。对6种不同来源的脂肪酶进行筛选,结果表明Lipozyme RMIM催化活性高、Sn-1,3位特异性强。以Lipozyme RMIM为催化用酶,考察了反应时间、反应温度、底物比(菜籽油与辛酸摩尔比)、加酶量、体系水分含量对酸解反应的影响。结果表明,在反应时间15 h,反应温度50℃,底物比1∶4,加酶量10%条件下,辛酸合成率达40%。     

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