通过商品化DHA藻油的脂肪酸组成推测其微藻属名

DHA是一种重要的功能性ω-3多不饱和脂肪酸.我国卫生部相继批准了寇氏隐甲藻、裂壶藻、吾肯氏壶藻DHA藻油为新资源食品.收集并分析了9个商品化DHA藻油的脂肪酸含量,结合文献数据,发现通过商品化DHA藻油的脂肪酸特征推测其微藻属名是可行的.其中寇氏隐甲藻DHA藻油中长链多不饱和脂肪酸只含DHA,几乎不合DPA.裂壶藻与吾肯氏藻DHA藻油中长链多不饱脂肪酸主要以DHA和DPA为主,DHA/DPA比例随藻种而恒定,几乎不随发酵条件而有明显变化;DHA/DPA比例在2～3的DHA藻油多半来自裂壶藻;DHA/DPA比例在4～6的DHA藻油既可能来自裂壶藻也可能来自吾肯氏壶藻.     

DHA藻油毒理学研究进展

DHA藻油是以裂壶藻(Schizochytrium sp.)或者吾肯氏壶藻(Ulkenia amoeboida)或者寇氏隐甲藻(Crypthecodinium cohnii)等藻种为原料,经生物发酵、提取、冬化、精制、脱色、除臭等过程制得富含DHA的油脂.DHA对人类智力和视力发育至关重要.由于人体不能直接合成,需要通...     

通过DHA藻粉的18S rDNA序列验证藻油脂肪酸组成推断DHA微藻属名

我国卫生部批准为新资源食品的DHA藻油包括产自裂壶藻(Schizochytrium sp.)、吾肯氏壶藻(Ulkenia ameoboida)和寇氏隐甲藻(Crypthecodinium cohnii)。通过对几种商品DHA藻粉的18S rDNA进行扩增、测序和比对,结合藻油的脂肪酸组成,对藻油的生产藻种进行了鉴定。结果表明,基于18S rDNA序列分析数据建立的系统进化树可进一步确定DHA微藻属名。     

60Co-γ射线辐射诱变寇式隐甲藻6号的技术研究

寇氏隐甲藻是产DHA的优良藻种,期望通过60Co-γ射线诱变提高其DHA的产率,实现商业化生产DHA。寇氏隐甲藻(Crypthecodium cohnii 6号)经不同剂量的60Co-γ射线分别辐照诱变,经分离培养获得了不同诱变剂量下藻体的致死率,并对它们的的生长时间、生长速率以及生物量进行了比较,以确定最佳诱变条件。实验结果表明诱变剂量3.0kGy~5.4kGy时,死亡率达到99.999%以上,诱变剂量为1.8kGy的寇氏隐甲藻经培养后生物量最高,并在开始培养后36h就达到最大生长速率,这为进一步研究提供了科学依据。     

寇氏隐甲藻发酵产DHA藻油的动力学模型研究

本文利用Logistic方程和Luedeking-Piret方程对寇氏隐甲藻发酵产DHA藻油动力学进行研究。通过测定寇氏隐甲藻在50 L发酵罐中生物量、油脂产量、DHA产量、葡萄糖浓度的变化,建立了菌体生长、产物形成和基质消耗的动力学模型,同时对试验值与模拟值进行了比较,平均相对误差大部分小于10%。通过对发酵过程的曲线拟合以及模型参数的计算,模型相关指数分别为:0.993、0.996和0.978,模型模拟计算结果与试验值能较好地吻合,说明所建立的发酵动力学模型能够较好地反映寇氏隐甲藻的发酵过程,为其工业化生产提供科学依据。     

寇氏隐甲藻不同破壁方法的研究

寇氏隐甲藻是海洋微藻的一种,在寇氏隐甲藻的细胞油脂中,二十二碳六烯酸的含量高达30%～50%。但长期以来,因为微藻的细胞壁很难破碎,导致油脂的提取率不高。运用超声波法、生物酶法,反复冻溶法等方法,对寇氏隐甲藻进行了破壁研究。结果表明,这些方法都对寇氏隐甲藻都具有一定的破壁作用,破壁后油脂的提取率也有了不同程度的提高,把酶法破壁和超声波法破壁结合起来,在酶解5 h后,再超声波1 h,破壁率可高达91.7%,油脂提取率提高了21.7%,破壁效果更为理想。     

寇氏隐甲藻突变株的糖、氮代谢对产油的影响

为了探索在寇氏隐甲藻(crypthecodinium cohnii)突变株的营养生长和油脂积累过程中对碳源和氮源的需求及其影响。通过对照组和5个不同的补糖试验组进行研究,各组经发酵7 d收获,并测定生物量、含油量、DHA含量和DHA产量。结果显示各组在发酵培养24 h时,碳消耗量约为22.5%,氮耗约为50%。随着不同时间的补糖,测定碳耗和氮耗虽有小幅度升降,但在144~168 h时碳耗、氮耗和碳/氮比基本稳定,各组间差异较小。研究表明,前72 h是寇氏隐甲藻生长的重要时期,当碳/氮比在15∶1左右时补糖最佳;当氮源耗尽时补糖不仅可以促进油脂的产生,而且对DHA的形成也是有利的。     

裂壶藻营养特性及其积累DHA的研究

为了研究裂壶藻营养代谢和无机盐对其生长及产DHA的影响。首先研究了3个批次的裂壶藻发酵产DHA过程中的生物量、油脂产量、DHA产量、糖耗、氮耗的变化;然后探索了无机盐离子对产脂过程的影响,并在以上最优条件的基础上在50 L发酵罐中进行验证,DHA产量达到最大值,为6.27 g/L,这为工业推广提供了理论依据,为降低生产DHA成本提供了可能。     

化学添加剂对裂壶藻突变株发酵产DHA的影响

为了研究外源化学添加剂对裂壶藻(Schizochytrium limacinum)突变株发酵合成脂肪酸(SFAs、PUFAs和DHA)的影响,采用基于气相色谱-质谱(GC-MS)联用技术分析裂壶藻突变株产油脂肪酸的组成。通过单因素和正交实验设计,优化了乙醇胺(ETA)、萘氧乙酸(BNOA)和水杨酸(SA)三种化学添加剂的最佳添加条件。结果表明,添加150 mg/L的乙醇胺(ETA)、10 mg/L萘氧乙酸(BNOA)和1 mg/L水杨酸(SA),裂壶藻突变株的DHA产量最高,达到6.18 g/L,比对照组提高了12.77%。综上所述,添加适量的化学添加剂可以提高裂壶藻突变株DHA的含量。     

裂壶藻补糖发酵及糖氮代谢对产油的影响

为了探索裂壶藻(Schizochytrium limacinum)突变株生长及产油过程中对碳源和氮源的需求,本文对发酵各阶段的碳源和氮源利用变化情况进行测定,并设定五个在不同时期的补糖实验组进行研究,分别观测各组各时期生物量、油脂产量。结果表明,前96 h是裂壶藻生长的重要时期,生物量大幅度增长,在发酵144~168 h时,油脂产量达到最大,各组经发酵7 d收获总的藻体,对生物量、油脂产量、DHA含量和DHA产量进行综合测定,结果表明,在发酵120 h时进行补糖为最佳时期,且油脂产量及DHA产量相比于对照组分别高出18.80%和22.44%。当氮源耗尽时补糖不仅可以促进油脂的产生,而且对DHA的形成也是有利的。     

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