南极磷虾脂质的亚临界提取及磷脂分析

研究了南极磷虾脂质的亚临界丁烷提取工艺。测定了南极磷虾脂质的酸值、过氧化值、氟含量、生育酚含量、虾青素含量、磷脂含量及磷脂种类组成、脂肪酸组成。结果表明,通过单因素试验确定了亚临界丁烷提取南极磷虾脂质的较佳工艺条件为:动态提取时间120 min(单次提取时间30min、提取4次)、提取压力1.0 MPa、提取温度40℃;在较佳工艺条件下南极磷虾脂质提取率为21.39%;提取的南极磷虾脂质的酸值(KOH)10.6 mg/g,过氧化值3.01 meq/kg,虾青素含量248.4mg/kg,生育酚含量67.7 mg/kg,磷脂含量28.68%,其中磷脂中磷脂酰胆碱占71.20%;磷脂酰胆碱中脂肪酸组成与甘三酯的基本一致,但磷脂酰胆碱中EPA和DHA含量明显高于甘三酯的。     

不同提取方法对樱桃仁油品质的影响北大核心CSCD

分别采用压榨法、有机溶剂法、超声波辅助法和超临界CO2萃取法4种方法提取樱桃仁油,通过比较不同方法提取樱桃仁油的提取率、理化性质、DPPH·清除能力及脂肪酸组成,探讨不同提取方法对樱桃仁油品质的影响。结果表明:采用超临界CO2萃取法樱桃仁油提取率最高,达到(97.61±0.86)%;4种提取方法所得樱桃仁油的酸值、过氧化值、色泽、水分及挥发物含量、不溶性杂质有较大差异,而碘值、皂化值、折光指数、相对密度特征性指标差异不大,且均具有一定的清除DPPH·的能力;4种提取方法所得樱桃仁油的脂肪酸组成和含量差异不大,亚油酸和油酸是樱桃仁油中的主要脂肪酸,不饱和脂肪酸含量大于80%。     

不同提取方法对樱桃仁油品质的影响

分别采用压榨法、有机溶剂法、超声波辅助法和超临界CO2萃取法4种方法提取樱桃仁油,通过比较不同方法提取樱桃仁油的提取率、理化性质、DPPH·清除能力及脂肪酸组成,探讨不同提取方法对樱桃仁油品质的影响。结果表明:采用超临界CO2萃取法樱桃仁油提取率最高,达到(97.61±0.86)%;4种提取方法所得樱桃仁油的酸值、过氧化值、色泽、水分及挥发物含量、不溶性杂质有较大差异,而碘值、皂化值、折光指数、相对密度特征性指标差异不大,且均具有一定的清除DPPH·的能力;4种提取方法所得樱桃仁油的脂肪酸组成和含量差异不大,亚油酸和油酸是樱桃仁油中的主要脂肪酸,不饱和脂肪酸含量大于80%。     

草鱼头磷脂制备工艺优化及抗氧化性能分析

为了得到较高纯度的草鱼头磷脂并分析其抗氧化性能,采用乙醇溶液浸提冷冻干燥草鱼头粉末制备磷脂,正交试验确定其最优工艺后,利用薄层层析(TLC)分析比较草鱼头磷脂种类的组成及含量,利用气相色谱-质谱联用技术分析磷脂的脂肪酸组成,并进行体外抗氧化能力测定。结果表明:磷脂制备最优工艺方案为:乙醇浓度80%,料液比1:6 g/mL,提取温度65℃,提取时间3 h,在此条件下,得到草鱼头磷脂的纯度为84.20%±0.65%,提取率为3.03%±0.06%。草鱼头磷脂主要含有磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、鞘磷脂(SM)、溶血磷脂酰胆碱(LPC)四种磷脂,其中PC的含量最高(60.00%±0.26%),其次为PE(20.00%±0.17%)。草鱼头磷脂脂肪酸组成以多不饱和脂肪酸(PUFA)为主(52.09%±0.59%),其中,C20:5n-3(EPA)和C22:6n-3(DHA)含量较高。体外抗氧化测定试验结果表明,草鱼头磷脂的羟自由基(·OH)清除能力和还原力能力都显著(P<0.05)优于对照的商品大豆磷脂。     

养殖大黄鱼各部位磷脂组分及其脂肪酸组成分析

为明确大黄鱼各部位磷脂组分及其脂肪酸组成,本实验选取大黄鱼头部、背肌、腹肌、内脏、尾部以及鱼卵为研究对象,分别测定各部位的磷脂含量、组分及其脂肪酸组成。结果表明:鱼卵中磷脂含量最高,为5.50 g/100 g。头部、背肌和腹肌磷脂组分一致,为溶血磷脂酰胆碱(LPC)和磷脂酰胆碱(PC);头部磷脂中LPC和PC的含量分别为39.23%、45.12%,背部分别为62.74%、36.12%,腹部分别为66.69%、33.31%。内脏磷脂组分为溶血磷脂酰胆碱(LPC)、磷脂酰肌醇(PI)和鞘氨醇磷脂(SM),含量分别为59.37%、12.77%、29.83%。鱼尾磷脂为LPC、PC和磷脂酰乙醇胺(PE),含量分别为21.41%、59.37%、19.22%。鱼卵磷脂为LPC、PI、PE和PC,含量分别为12.30%、1.09%、9.12%、76.36%。脂肪酸组成分析表明大黄鱼各部位富含多不饱和脂肪酸,其中鱼卵磷脂中多不饱和脂肪酸占比43.1%,明显优于大黄鱼其他各部位。研究结果说明大黄鱼是一种富含磷脂功能因子的海洋鱼类。     

提取方法对大豆油脂体组成及氧化稳定性的影响

以大豆为原料,比较缓冲溶液法、水相法和酶法3种提取方法对大豆油脂体提取率、组成、脂肪酸组成、磷脂、生育酚、ζ-电势和粒径的影响,以及对大豆油脂体氧化稳定性的影响。试验结果表明,酶法提取大豆油脂体的提取率(19.74±0.14)%显著高于缓冲溶液法(12.76±0.14)%和水相法(6.67±0.32)%的提取率(P<0.05);不同方法提取的大豆油脂体组成、脂肪酸组成、磷脂和生育酚含量、ζ-电势和粒径均存在显著性差异(P<0.05)。控制贮藏温度60℃,贮藏第0天时,用缓冲溶液法、酶法和水相法提取的大豆油脂体的过氧化值分别为(1.67±0.14),(1.84±0.10),(1.64±0.00)μg/mL,无显著性差异(P>0.05);水相法提取的油脂体的硫代巴比妥酸值(TBARS)为(1.14±0.01)μg/mL,显著高于酶法(1.02±0.02)μg/mL和缓冲溶液法(1.09±0.02)μg/mL(P<0.05);缓冲溶液法大豆油脂体TBARS显著高于酶提取法(P<0.05);酶法提取的油脂体的酸价(0.71±0.02)μg/mL显著低于水相法(0.96±0.13)μg/mL和缓冲溶液法(0.93±0.09)μg/mL(P<0.05);水相法和缓冲溶液法无显著差异(P>0.05)。不同提取方法获得的大豆油脂体在组成和理化性质上均存在显著差异(P<0.05),由酶法提取的大豆油脂体提取率和脂肪含量最高且稳定性最好。     

人乳的磷脂组成与脂肪球结构

采用核磁共振磷谱(~(31)P-NMR)测定不同泌乳期、不同胎龄的人乳磷脂组成,结果显示足月儿和早产儿人乳中,磷脂的主要组成均为鞘磷脂(SM)、磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、磷脂酰乙醇胺缩醛磷脂(EPLAS)、磷脂酰肌醇(PI)和磷脂酰丝氨酸(PS),其中SM含量最高,其次为PC和PE,PS和PI含量最低。总磷脂含量在相同胎龄不同泌乳期以及相同泌乳期不同胎龄间均无显著性差异。在磷脂组成上,足月儿人乳中PI在初乳和过渡乳中的含量分别为(4.14±0.42)%和(3.66±0.66)%,显著高于成熟乳中的(2.79±0.09)%;早产儿人乳中PC在初乳和过渡乳中的含量分别为(30.74±2.03)%和(29.40±2.37)%,显著高于成熟乳的(27.55±2.42)%,此外EPLAS含量随泌乳期的延长逐渐降低,PE含量逐渐升高,PE+EPLAS在不同的泌乳期无显著性差异。另外,足月儿和早产儿的脂肪球结构无明显差异,磷脂构成的膜包裹体积平均粒径约为5μm的脂肪球。     

六种鱼鱼头磷脂的组成及脂质脂肪酸分析

为研究海水鱼和淡水鱼鱼头磷脂及脂质脂肪酸组成的差异,以海水鱼(马鲛鱼、巴浪鱼、金鲳鱼)和淡水鱼(罗非鱼、鲫鱼、鲢鱼)鱼头为研究对象,利用Floch法提取6种鱼鱼头总脂;硅胶柱层析法将总脂分离收集中性脂、糖脂和磷脂;薄层层析(thin layer chromatography,TLC)分析比较6种鱼鱼头磷脂种类的分布、组成;气相色谱(Gas chromatography,GC)分析6种鱼鱼头脂质的脂肪酸组成。结果表明,6种鱼鱼头中提取率最高的脂质类型为中性脂,占总脂的48.98%~77.84%,其次为磷脂,占总脂的5.93%~22.86%,糖脂提取率最低,占总脂的3.67%~15.91%。鱼头磷脂中共检出4种磷脂组分,分别为磷脂酰乙醇胺(Phosphatidylethanolamine,PE)、磷脂酰胆碱(Phosphatidylcholine,PC)、鞘磷脂(Sphingomyelin,SM)、溶血磷脂酰胆碱(Lysophosphatidylcholine,LPC),其中PC明显高于其他磷脂组分。脂质中均含有较高含量的多不饱和脂肪酸(Poly-unsaturated fatty acid,PUFA),其中以二十二碳六烯酸(docosahexaenoic acid,DHA)为主,且均含有二十碳五烯酸(eicosapntemacnioc acid,EPA),海水鱼和淡水鱼鱼头磷脂中DHA和EPA占总脂肪酸的比例最高,分别为18.39%~21.43%和5.61%~10.38%,且海水鱼鱼头中以DHA和EPA为主的PUFA含量高于淡水鱼鱼头。因此,海水鱼鱼头是提取n-3多不饱和脂肪酸的潜在资源,尤其是制备n-3多不饱和脂肪酸型磷脂的良好来源。     

脂肪酶Bakezyme LFP水解大豆粉末磷脂研究

以酸值为指标,通过单因素实验和正交实验确定了脂肪酶Bakezyme LFP在水相中水解大豆粉末磷脂的最佳工艺条件为:反应温度为50℃,反应时间为8h,p H为5.0,加酶量为8%,底物质量浓度为25mg/m L。在该工艺条件下,大豆磷脂水解产物酸值为65.2mg KOH/g。利用气相色谱-质谱联用仪分析了水解前后大豆磷脂的脂肪酸组成,结果表明水解后饱和脂肪酸含量明显下降,不饱和脂肪酸含量明显增加,说明脂肪酶Bakezyme LFP主要水解大豆磷脂1位上脂肪酸,具有磷脂酶A1的特性。利用高效液相色谱分析水解前后大豆磷脂的磷脂酰乙醇胺(PE)和磷脂酰胆碱(PC)含量,结果表明大豆磷脂中PE、PC发生水解,生成溶血磷脂。     

海参肠脂质的提取及组成研究

以海参肠为原料,采用有机溶剂提取海参肠中的脂质,考察海参肠自溶处理、p H、热变性处理对海参肠脂质提取率的影响,并分析海参肠脂质组成和脂肪酸组成。结果显示,自溶处理对脂质提取率无显著影响,而p H和热变性处理对脂质提取率影响显著。在p H3条件下提取海参肠脂质,提取率为(5.40±0.15)%,回收率达到索氏提取法的(70.40±1.92)%。海参肠脂质中不饱和脂肪酸含量达(84.62±0.82)%,多不饱和脂肪酸含量达(51.32±2.04)%。海参肠脂质中含有24种脂肪酸,包括9种饱和脂肪酸,9种单不饱和脂肪酸,6种多不饱和脂肪酸,其中二十碳五烯酸相对含量最高达(30.97±0.46)%。海参肠脂质以甘油三酯、游离脂肪酸、甘油二酯、胆固醇、甘油一酯和磷脂形式存在。     

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.     

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.     

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.     

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.     

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.