油酰肌氨酸钠与HAC和AEO-9的复配物的表面活性和乳化力

通过滴体积法测量溶液的表面张力，研究油酰肌氨酸钠与阳离子聚合物HAC和非离子表面活性剂AEO-9的复配效果，并比较它们对石蜡和甘油酯的乳化效果。试验结果表明，复配HAC和AEO-9都可以提高油酰肌氨酸钠的表面活性，包括降低CMC和γcrnc，但AEO-9的复配效果更优。复配后，油酰肌氨酸钠对石蜡的乳化效果明显提高，其中，又以油酰肌氨酸钠-HAC体系更好。这与阳离子聚合物自身对乳液稳定性的提升有关。但复配后的油酰肌氨酸钠对甘油酯的乳化性能不及OP-10和AEO-9。     

10种脂肪酰乙醇胺制备工艺优化及其结构表征北大核心CSCD

为了优化脂肪酰乙醇胺的制备工艺,以油酸甲酯和乙醇胺为原料,采用无溶剂法制备油酰乙醇胺,采用单因素实验优化了反应条件。然后以10种脂肪酸甲酯为原料,考察了该反应方法的普适性,并对制备得到的10种脂肪酰乙醇胺的结构进行了表征。结果表明:制备油酰乙醇胺的最佳工艺条件为无溶剂、油酸甲酯与乙醇胺物质的量比1∶5、反应温度100℃、反应时间15 h,在此条件下油酰乙醇胺产率为76.52%;在最佳工艺条件下考察了反应底物的普适性,得到10种脂肪酰乙醇胺目标化合物,其产率在53%~87%之间,并通过核磁氢谱、碳谱以及高分辨质谱确证了目标化合物的结构。该方法反应条件绿色无污染,分离纯化成本低,操作简易,且可以获得克级以上的高纯度脂肪酰乙醇胺,可为以后开展脂肪酰乙醇胺生物活性研究提供足够的样品。     

棉籽油催化裂化制取轻质燃料油的研究

以棉籽油为原料，采用催化裂化工艺制取轻质燃料油，考察了反应温度、剂油比、反应时间对棉籽油催化裂化制取轻质燃料油的影响。以燃料油产率最大值为目标函数，利用响应面法优化操作变量，并建立了棉籽油催化裂化制取燃料油的数学模型，其计算结果与试验数据吻合良好；试验结果表明适宜的反应条件为：反应温度426℃，反应时间50S，剂油比7．8：1（m／m）；在此条件下有机馏分（≤〈360℃）产率65．6％，汽油馏分（≤205℃）产率33．7％，气体产率11．6％；制备的燃料油馏分可以作为石化汽油、柴油的调和组分。     

高效液相色谱法测定鸡精中呈昧核苷酸含量

建立了高效液相色谱法测定鸡精中呈味核苷酸含量方法。样品经水超声提取。采用液相色谱仪进行检测,色谱柱为C18色谱柱,流动相为V（甲醇）：V（乙酸铵溶液）=5：95,检测波长为254nm。结果表明,鸟苷酸二钠和肌苷酸二钠分离效果良好（R=2．O）,可分别准确定量。在1μg／ml-100μg／ml范围内鸟苷酸二钠和肌苷酸二钠回归方程分别为：Y=10．6825X＋1．5953,r=0．99995;Y=8．9096X＋0．13404,r=0．99997。方法回收率为99．1％、98．7％。     

醇洗豆粕对大豆分离蛋白功能性质的影响(Ⅲ)--起泡性能

探讨了醇洗豆粕对大豆分离蛋白起泡性能的影响。与未经处理的大豆分离蛋白相比，由于醇洗豆粕去除了抑制泡沫稳定的一些醇溶物质如磷脂酰胆碱等，使分离蛋白表面电荷改变，从而减少了膜中蛋白组分之间的静电斥力，增强了泡沫的稳定。通过正交实验优化，生产起泡型大豆分离蛋白的最佳工艺条件为：乙醇浓度75％(V／V)、浸提温度50℃、浸提时间45min、固液比1：6。所得产品的蛋白含量(干基)为97．86％，蛋白质分散指数为95．67％，起泡度为140％，泡沫稳定性(失水率)为37．50％。     

桑白皮壳聚糖的制备研究

以桑白皮为原材料制备了壳聚糖，并采用正交试验法研究了氢氧化钠处理质量分数、处理时间、温度及桑白皮与氢氧化钠溶液配比等因素对桑白皮壳聚糖产率的影响。结果表明，处理温度是影响桑白皮壳聚糖产率的最主要的因素，氢氧化钠的质量分数次之，处理时间和桑白皮与氢氧化钠溶液配比对壳聚糖的产率没有影响。通过极差、方差分析，得到桑白皮壳聚糖的最佳制备条件：V（氢氧化钠）：V（乙醇）：4：1；m（桑白皮）：m（氢氧化钠溶液）=1：10；氢氧化钠溶液的质量分数为30％；氢氧化钠处理时间为4h；温度为120℃。所制备的桑白皮壳聚糖的脱乙酰度为30％，产率为1．5％，并用紫外、红外表征了产品。     

高效液相色谱法测定蛋白核小球藻中的叶黄素

采用反相高效液相色谱法(RP-HPLC)分离测定了蛋白核小球藻中的叶黄素。样品制备采用甲醇-二氯甲烷(体积比为2：1)混合溶剂为叶黄素提取剂，所用色谱柱为Nova-Pak~(?)C_(18)不锈钢柱，以甲醇-乙腈-水(体积比为80：10：10)和甲醇-乙腈(体积比为40：60)为流动相，线性梯度洗脱，流速0.8mL／min，在447nm下用光电二极管阵列检测器(DAD)检测。测定结果显示，在0～60mg／L范围内，标准曲线呈良好的线性关系(r=0.9999)，叶黄素的保留时间为11.25min，浓度的相对标准偏差为0.49％(n=6)，平均加样回收率为99.7％。该法简单、快速、准确。     

漆脂酰肌氨酸表面活性剂的合成与性能研究

以漆脂为原料,经过硫酸催化水解,生成漆脂脂肪酸,再与氯化亚砜反应生成漆脂脂肪酰氯,然后采用肖顿-鲍曼(Schotten-Baumann)缩合法,在弱碱性条件下,漆脂脂肪酰氯与肌氨酸钠盐进行缩合反应,再经过酸化、萃取等过程,制得漆脂酰肌氨酸。采用红外光谱和核磁共振碳氢谱对其结构进行表征,并对产物钠盐的表面性能进行分析。结果表明,合成产物为漆脂酰肌氨酸,漆脂酰肌氨酸钠盐的临界胶束浓度为6. 733×10~(-4)mol/L,表面张力为22. 845 m N/m,具有较好的表面活性。当漆脂酰肌氨酸钠盐浓度为0. 01 mol/L时,从乳化的液体石蜡中分出10 m L水的时间为90 s,对低极性溶剂的乳化效果较差,但漆脂酰肌氨酸钠盐的起泡和稳泡性能较好,起泡高度为130 mm,5 min后降至115 mm。     

尿素包合法分离欧李仁油中油酸的研究

以我国特有的天然固沙植物欧李的种子油为原料，采用正交试验设计分析方法，用尿素包合分离法纯化、制备高纯油酸，对欧李仁油油酸的分离工艺条件进行了优化，得到的最佳工艺条件为：结晶温度T1为10℃，结晶温度T2为-10℃，尿素：脂肪酸(W／W)为1．5：1，甲醇浓度90％，在优化工艺条件下，油酸提取率：87．3％，纯度：97．6％；油酸样品硅胶柱层析处理后，总提取率为76．9％，油酸含量为99．3％。     

HPSEC法测定食用棕榈油中氧化甘油三酯聚合物

试验采用制备型快速柱层析-高效体积排阻色谱(HPSEC),先通过制备型快速柱层析技术,将食用棕榈油中的极性组分提取出来。再采用高效体积排阻凝胶色谱对极性组分进行色谱分离分析,以甘油三酯为标准,凡是在甘油三酯之前分离的物质为油脂的氧化甘油三酯聚合物,最后采用峰面积归一化法计算出氧化甘油三酯聚合物在极性组分中的含量,再根据极性组分在全油中的含量,计算出全油中氧化甘油三酯聚合物的含量。结果表明:该方法检出限为0.000 1%,标准品易购得,检测数据稳定、准确,RSD10%。该方法能满足食用棕榈油的检测要求。     

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.     

Detection of adulteration of locust bean gum with guar gum by capillary electrophoresis and polarized light microscopy

Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH₃CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH₂PO₄-20.6 mM Na₂B₄O₇ buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.