溶剂法精制磷脂酰胆碱的研究

为了提高磷脂产品中磷脂酰胆碱(PC)的含量,研究了以浓缩大豆磷脂为原料,采用丙酮和乙醇作溶剂,制备高含量磷脂酰胆碱.用丙酮脱油时,在料溶比为15:200、提取时间15 min、提取温度40℃的最佳脱油工艺条件下,得到丙酮不溶物含量为97.6%的中间产物--粉末磷脂.用乙醇提取富集其中的磷脂酰胆碱,通过单因子试验,研究了粉末磷脂与溶剂的比例、乙醇浓度、提取温度、时间和次数对PC含量和提取率的影响.试验结果表明,在乙醇浓度95%,固液比1:20,提取时间30 min,温度35℃,抽提次数2次的条件下,PC含量和提取率均较优.在最佳试验条件下,PC含量可提高到45.1%,提取率为62.0%.     

己烷体系中磷脂酶A1催化卵磷脂乙醇解制备溶血卵磷脂的研究

在己烷体系中,采用磷脂酶A1催化卵磷脂乙醇解制备溶血卵磷脂。首先通过单因素试验分别考察了加酶量、加水量、底物比、温度和溶剂比对卵磷脂乙醇解制备溶血卵磷脂的影响,并在此基础上利用响应面法对反应工艺进行了优化。最终确定最佳工艺条件为:卵磷脂1.5 g,加酶量40μL/g(磷脂酶A1/卵磷脂),加水量25μL/g(水/卵磷脂(PC)),底物比:1∶3(PC/无水乙醇,mol/mol),温度30℃,溶剂比:1∶2(PC/正己烷,W/V),反应时间3.55 h,溶血磷脂转化率达98.3%。结果表明,磷脂酶A1可以催化磷脂酰胆碱乙醇解反应制备溶血磷脂酰胆碱。     

鲢鱼头磷脂的提取工艺优化及乳化性能研究

用乙醇溶液提取鲢鱼头中的磷脂并分析其乳化性能。通过单因素试验和正交试验优化鲢鱼头磷脂的提取条件;利用薄层层析分析鲢鱼头磷脂的组成,气相色谱-质谱联用仪分析鲢鱼头磷脂脂肪酸组成并与大豆卵磷脂比较;分别探究了磷脂质量浓度、离子强度、p H和温度对磷脂乳化特性的影响。结果表明:鲢鱼头磷脂的最优提取条件为乙醇体积分数80%、料液比1∶10、提取温度35℃、提取时间3 h,在此条件下磷脂纯度为74. 45%,磷脂产物提取率为3. 35%。鲢鱼头磷脂PC和PE的含量高于大豆卵磷脂;两者脂肪酸都以多不饱和脂肪酸为主,但鲢鱼头磷脂以C22∶6n-3为主,大豆卵磷脂以C18∶2n-6为主。在试验范围内,磷脂的乳化能力随着其质量浓度的增加而增强,且鲢鱼头磷脂的乳化能力略低于大豆卵磷脂的;无离子环境中两种磷脂的乳化能力较好;鲢鱼头磷脂和大豆卵磷脂皆在pH为7时乳化效果最佳;低温条件下两种磷脂乳化能力较好。总体来看,鲢鱼头磷脂的乳化特性与大豆卵磷脂的接近。     

大豆磷脂酰乙醇胺的分离及纯化

以提取卵磷脂(PC)后的大豆粉末磷脂为原料,以碱性乙醇为溶剂提取磷脂酰乙醇胺(PE),并进行冷冻纯化。在单因素实验的基础上,以PE得率为指标,响应面优化实验确定了PE的最佳提取条件为:提取温度45℃,料液比1∶20,乙醇碱浓度V(无水乙醇)∶V(25%氨水)=100∶2,提取时间50 min,提取次数2次。在最佳条件下,PE得率为79.53%,含量为48.42%;当冷冻温度为-15℃,冷冻时间为8 h时,PE含量提升到72.73%,得率为66.71%。     

浸出芝麻油中芝麻木酚素提取工艺的研究

以浸出芝麻毛油为原料,乙醇为提取剂,进行芝麻木酚素的提取。通过单因素试验和正交试验确定了最佳的芝麻素提取工艺条件,并利用高相液相色谱仪对得到的芝麻木酚素粗品进行芝麻素和芝麻林素含量测定。结果表明:芝麻素提取工艺的最佳条件为浸提次数3次、料液比1∶4、提取温度60℃、乙醇体积分数95%、搅拌时间0.5 h、静置时间2 h、搅拌速度400 r/min,在此条件下芝麻素提取率为86.99%;得到的芝麻木酚素粗品中芝麻素含量为48.73%,芝麻林素含量为5.71%。     

芝麻油渣中磷脂的超临界提取及分析研究

以芝麻油渣为原料提取芝麻磷脂,参照GB/T 5537-2008《粮油检验磷脂含量的测定》,采用优化的钼蓝比色法建立了磷脂的分析方法,并对芝麻油渣中磷脂含量进行测定,研究超临界CO_2提取芝麻磷脂过程中萃取压力、萃取温度、萃取时间对出油率的影响,确定最佳提取工艺条件。试验结果表明,采用优化的钼蓝比色法测定分析芝麻油渣中磷脂含量,测定快速,准确度较高,试验范围内得到的最佳提取工艺条件为CO_2流量10 L/h,原料粒径范围20目~40目,萃取压力18 MPa,萃取温度45℃和萃取时间120 min,在此条件下油脂萃取率达到12.5%。将超临界萃取得到的油脂进行水化脱胶,离心分离得到磷脂富集层,用正己烷溶解并用丙酮沉淀,得到芝麻磷脂,磷脂的提取率为35.58%,所得磷脂的纯度为65.90%。     

脱糖大豆粉末磷脂中磷脂酸的分离

以低磷脂酰胆碱(PC)含量的脱糖大豆粉末磷脂为原料,建立了使用酸性乙醇为溶剂分离高纯度磷脂酸的方法。探讨了提取温度、料液比、提取时间、提取次数、酸醇比和pH等因素对磷脂酸提取效果的影响,并在单因素实验的基础上通过响应曲面优化实验进行分析,得到分离磷脂酸的最佳工艺条件为:提取温度42℃,料液比1∶37(m/m),酸醇比1.2∶100(V_(25%HCl)∶V_(无水乙醇)),提取时间70min,沉淀pH为8。在最佳条件下,产物的HPLC分析表明,产品中PA含量为80.96%,回收率为70.53%。     

生物柴油副产物甘油中磷脂酰胆碱的提限纯化研究

以生物柴油副产物甘油中分离得到的粗磷脂为原料,采用乙醇提取、减压蒸馏浓缩制备较高纯度磷脂酰胆碱(PC).通过响应曲面设计考察了料液比、提取温度、提取时间、搅拌速度对提取率的影响.优化的最佳提取条件为:液料比42:1(mL/g),提取温度46℃,提取时间38min,搅拌速度328r/min,提取一次.经实验验证,提取率达到78.2%,Pc含量由原来的46%提高到77%.     

新疆胡麻卵磷脂提取工艺及含量测定的研究

本研究建立了以新疆本地胡麻油脚为原料的卵磷脂提取工艺及双波长薄层扫描法测定胡麻卵磷脂中磷脂酰胆碱含量的分析方法。提取工艺为水化油脚真空浓缩脱水,丙酮脱油得粗磷脂;粗磷脂用超临界流体二氧化碳萃取纯化得磷脂;乙醇提取后最终得到以磷脂酰胆碱为主的卵磷脂。含量测定结果表明胡麻卵磷脂中磷脂酰胆碱的含量为62.4%,平均回收率为99.6%,RSD=3.42%。方法经济实用、结果可靠。     

鸭蛋黄卵磷脂的提取与精制

以鸭蛋黄为原料,采用乙醇提取法提取鸭蛋中的卵磷脂,设计了四因素正交试验。结果表明,在分离剂(酶)添加量0.05%,乙醇体积分数为90%,提取温度40℃,提取时间60 min条件下,提取粗卵磷脂效果最佳,可制得卵磷脂含量约为80%的粗卵磷脂,得率为10%。进一步用ZnCl2沉淀纯化卵磷脂,对不同浓度ZnCl2进行对比试验,结果表明,40%ZnCl2纯化粗卵磷脂的回收率可达90.8%,薄层层析结果表明只有卵磷脂一个斑点。     

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.     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

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.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.