杜氏盐藻β-胡萝卜素提取皂化工艺参数优化

以甲醇-丙酮(20∶80,V/V)为流动相,建立杜氏盐藻β-胡萝卜素HPLC-DAD检测方法。采用外标法定量,对杜氏盐藻β-胡萝卜素的提取皂化工艺参数进行优化。研究结果表明,所选6种溶剂中,95%乙醇的提取效果最好。对选取的杜氏盐藻粉皂化,使胡萝卜素的得率从0.350%提高到0.425%,提高了21.43%。优化提取的最佳工艺参数是:提取温度25℃、时间0.7 h、液固比200 m L/g。此条件下杜氏盐藻β-胡萝卜素得率为0.395%。皂化的最佳工艺参数是:皂化温度25℃、皂化时间2 h、KOH甲醇溶液质量浓度0.1 g/m L。采用此提取皂化工艺,杜氏盐藻β-胡萝卜素的最终得率为0.428%。     

三种微藻油脂肪酸组成和理化性质分析

对3种海水微藻油含量、脂肪酸组成和油脂的理化性质进行分析。结果表明:盐藻油、螺旋藻油和小球藻油含量分别为17.69%、6.36%和11.64%,棕榈酸、油酸、亚油酸和亚麻酸是杜氏盐藻油和小球藻油的主要脂肪酸组分,而螺旋藻油主要含有棕榈酸、亚油酸和γ-亚麻酸;盐藻、螺旋藻和小球藻油均具有较高的C/H值,3种盐藻油的C/H值分别为7.35、7.32和7.58;3种微藻油酸值分别为盐藻油12.64mg KOH/g、螺旋藻油17.65mg KOH/g和小球藻油9.8mg KOH/g;热值分别为盐藻油36.07MJ/kg、螺旋藻油37.01MJ/kg和小球藻油35.00MJ/kg;3种微藻油酸值和黏度均较高,流动性较差。     

超声波辅助提取杜氏盐藻油脂工艺研究

对杜氏盐藻油脂的超声波提取工艺进行了研究,采用响应面分析法分析了液固比、超声时间和超声温度对盐藻油脂得率的影响,并建立了相应的预测模型。方差分析的结果表明,液固比、超声温度和超声时间对油脂得率都有显著影响(P<0.005),液固比的二次方项(P<0.005)和超声温度的二次方项(P<0.01)对油脂得率有显著影响,并且超声温度和时间存在交互作用(P<0.05),考虑到提取效率、成本和可行性,利用约束复合形法对结果进行优化,得到的最佳工艺参数为:在选用丙酮为提取溶剂的条件下,液固比29∶1 mL/g、超声时间47 min、超声温度48℃。在最佳工艺参数下,盐藻油脂得率为16.03%,与预测结果相符。     

秸秆，米糠发酵液对极端嗜盐绿色杜氏藻生长的影响

极端嗜盐绿色杜氏藻是迄今发现的最耐盐的真核光合生物，内含丰富的多种活性物质，受到了国内外学者的广泛关注。对极端嗜盐绿色杜氏藻的营养强化进行探讨，以秸秆和米糠的发酵液作为营养强化物质，用对比法研究发酵液含量及盐度对绿色杜氏藻生物量的影响。结果表明最适宜杜氏藻生长的含量是：秸秆和米糠的发酵液含量都为0．5mL／100mL；最适宜杜氏藻生长的盐度是：秸秆发酵液与米糠发酵液皆为150Be’，并且在同含量及同盐度下米糠发酵液更有利于极端嗜盐绿色杜氏藻的生长。     

碳源对盐生杜氏藻(Dunaliella salina)生长及其β-胡萝卜素积累的影响

研究了NaHCO(30,3,6,9,12,15mmol/L)对盐生杜氏藻生长和β-胡萝卜素积累的影响,结果表明,12mmol/L的NaHCO3对杜氏藻(D.salina),生长最合适,细胞最高密度为84.6×104cell/mL,对照组仅为36.7×104cell/mL;在实验范围内,β-胡萝卜素含量随NaHCO3浓度的升高而增加,15mmol/L组有最高的β-胡萝卜素含量104.6mg/g,对照组仅为60.8mg/g;叶绿素a最大含量135mg/g也出现在15mmol/L组,对照组为97mg/g;接种6d内藻液pH值急剧上升,后几天在波动中下降;接种前五天NaHCO3消耗很快,5d～10d消耗较慢,建立了NaHCO3吸收的动力学方程;较高的NaHCO3有利于细胞蛋白质的合成。     

铁、钙离子补料对杜氏盐藻生长的影响

通过原子吸收光谱测定了杜氏盐藻对钙、镁、钾、铁四种离子的消耗速率,构建金属离子含量限制型培养基,研究了补加金属离子对杜氏盐藻生长光合速率、色素含量的影响。结果表明,对数期杜氏盐藻细胞对铁离子与钙离子的消耗呈线性降低,每增殖106个细胞分别消耗0.042μg的铁离子与0.708μg的钙离子,而在稳定期后,钙、铁离子浓度继续下降。生长时期中钾离子与镁离子的含量变化不显著。铁、钙离子补料能恢复杜氏盐藻的生长,但光合活性与色素含量变化较补料前的对数期光合速率与色素含量要低,但总类胡萝卜素含量要高于补料前对数期的。培养到稳定期的培养基经过回收补加有限的铁、钙离子后,细胞生长延滞期消失,但稳定期细胞浓度降低。回流培养基对数期细胞的光合速率与叶绿素含量降低,但是总类胡萝卜素含量升高。     

基于统计学和营养学的三种藻粉蛋白质营养价值评价与方法分析

采用主成分分析法、模糊识别法、氨基酸含量比值法和氨基酸比值系数法,分析了丝路寒旱区的小球藻、螺旋藻和杜氏盐藻藻粉蛋白质的营养价值,并对4种分析方法进行了比较。结果表明:丝路寒旱区的小球藻、螺旋藻和杜氏盐藻藻粉蛋白含量差异显著(P<0.05),以小球藻藻粉蛋白含量最高为70.77 g/100 g·DW,且均含有17种氨基酸,包括除色氨酸外的7种人体必需氨基酸,必需氨基酸占总氨基酸的质量分数均接近FAO/WHO氨基酸模式谱。三种藻粉蛋白质的贴近度分别为0.879、0.982和0.906;第一限制氨基酸均为甲硫氨酸;氨基酸比值系数分由高到低为小球藻（82.89）>螺旋藻（81.78）>杜氏盐藻（74.46）。主成分分析提取出4个主成分,累计方差贡献率为98.305%,可较好反映藻粉蛋白质氨基酸综合品质。综合四种评价方法的特点,氨基酸比值系数法和模糊识别法均对蛋白质中必需氨基酸从生物吸收的角度开展分析,但就计算方法而言,氨基酸比值系数法更严谨。本研究中模糊识别法与主成分分析法的结果虽然是一致的,但采用主成分分析法分析蛋白质中代表性氨基酸种类可能更好些。FAO/WHO推荐的蛋白质E/N和E/T值分析法,仅关注的是必需氨基酸的量,没考虑生物吸收必需氨基酸的特点。综上,丝路寒旱区三种藻粉蛋白质的营养价值依次为小球藻>螺旋藻>杜氏盐藻。     

极端嗜盐绿色杜氏藻混合培养技术的研究

极端嗜盐绿色杜氏藻(D.viridis)是一种单细胞的海洋微藻,由于其富含多种营养物质、具有极端嗜盐性及对环境具有极强的适应性而引起国内外研究者的兴趣.本文试图通过试验的方法讨论三种营养物质葡萄糖、蛋白胨、卤虫干粉发酵液对杜氏藻生物量的影响.结果表明最适宜杜氏藻生长的三种营养物质的浓度范围是:葡萄糖为70g/L～90g/L,干粉发酵液为0.4g/L～0.8g/L,蛋白胨为4g/L～6g/L.     

Fe对两株盐生杜氏藻(Dunaliella salina)生长和β-胡萝卜素积累的影响

研究了柠檬酸铁对两株盐生杜氏藻Dunaliella salina OUN04和D.salina OUN09生长和色素积累的影响,结果表明,D.salina OUN04生长最适的Fe浓度为0.05mmol/L,细胞密度达111.5×104cell/mL,0.25mmol/LFe组最低(70×104cell/mL);最大β-胡萝卜素含量(83.2mg/g)出现在0.25mmol/LFe浓度组中;Fe浓度为0.25mmol/L时有最大的叶绿素a含量(98.4mg/g);建立了杜氏藻对Fe吸收的动力学方程。D.salina OUN09生长最适的Fe浓度为0.05mmol/L(密度131×104cell/mL),最大β-胡萝卜素含量为130.2mg/g(0.05mmol/LFe组),对照组仅为70.4mg/g。     

杜氏盐藻β-胡萝卜素超高压提取工艺优化

对杜氏盐藻β-胡萝卜素超高压辅助提取工艺参数进行优化研究,结果表明,6种溶剂中,无水乙醇的提取效果最好。在超高压辅助提取条件下,各溶剂的β-胡萝卜素得率排序为无水乙醇石油醚95%乙醇三氯甲烷乙腈乙酸乙酯;建立了超高压辅助提取杜氏盐藻β-胡萝卜素的数学模型,确定最佳工艺参数:液固比483m L/g,超高压压力346 MPa,保压时间13.7 min,结果β-胡萝卜素得率的预测值为1.07%。在优化条件下,β-胡萝卜素得率测定值为1.02%,说明提取模型的适应性良好。与常规的回流提取方法相比,超高压技术显著提高了杜氏盐藻β-胡萝卜素提取效率。     

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