紫外分光光度法测定栀子中西红花苷的含量

目的:利用紫外分光光度法测定栀子中西红花苷的含量。方法:西红花苷线性关系分析及该方法的精密度、重现性、稳定性和回收率考察。结果:栀子中西红花苷的平均含量为0.928%,RSD(%)0.816。结论:该方法具有较好的线性关系,精密度、重现性、稳定性和回收率都符合要求(RSD3%);此法可以作为栀子特征成分检验的依据,为其质量评价提供前期探索。     

桅子黄多酚含量与抗氧化活性的相关性研究

目的：揭示栀子黄抗氧化能力是否与多酚含量有关,为栀子黄中抗氧化能力成分的确定提供线索。方法：分别采用还原能力实验、DPPH自由基清除能力实验和亚铁离子螯合实验测定西红花苷、绿原酸、栀子粗提物和栀子黄的抗氧化活性,同时分别采用HPLC和UV来测定栀子粗提物和栀子黄中西红花苷和多酚的含量。结果：在还原能力和DPPH自由基清除活性模型中,栀子黄色素中起抗氧化作用的主要化学成分是多酚类,而不是西红花苷。另一方面．与前两个模型不同,西红花苷和多酚类成分都具有明显的亚铁离子螯合活性,栀子黄中具有螯合活性的主要化学成分同时包括西红花苷和多酚类。结论：结合前期研究结果推测,栀子黄抗氧化作用的主要化学成分是多酚类．而西红花苷具有明显的亚铁离子螯合活性。     

栀子黄A238nm/A440nm 值与西红花苷和栀子苷相关性研究

目的：采用TLC、HPLC 和紫外分光光度法(UV)研究栀子黄OD 值(栀子黄中栀子苷的最大吸光度A238nm 与西红花苷的最大吸光度A440nm 的比值)与栀子苷含量的关系。方法：采用硅胶柱层析从栀子中分离西红花苷纯品,然后分别采用TLC、HPLC 和UV 来定性和定量分析栀子乙醇提取部位和经大孔吸附树脂精制的栀子黄,并计算波长238nm 和440nm 处的百分比吸光系数及OD 值。结果：经过对以上数据的分析,发现西红花苷本身在波长238nm处有明显紫外吸收,采用OD 值来控制栀子黄中的栀子苷将高估栀子苷含量。结论：栀子黄中栀子苷的控制不宜采用OD 值作为评价指标,而应采用具有分离功能的高效液相色谱法来作为质量控制的手段。     

炒制温度和时间对栀子中栀子苷、绿原酸和鞣质含量的影响

目的考察炒制温度和时间对栀子中栀子苷、绿原酸和鞣质含量的影响。方法以CY640A型炒药机,在投药量一致的条件下,在多种温度下分别炒制栀子,制备不同受热条件的栀子供试品。用HPLC法分别测定各供试品栀子苷和绿原酸的含量,用皮粉法测定各供试品鞣质的含量。结果在180～240℃之间,随着炒制温度升高,时间延长,栀子苷、绿原酸含量呈逐渐降低的趋势,鞣质含量呈先升后降的趋势,220℃炒制21min的供试品鞣质含量最高。结论炒制温度和时间对栀子中栀子苷、绿原酸和鞣质含量有明显的影响;此方法为探讨栀子的炮制机理提供了实验依据。     

RP-HPLC测定小儿清热片中栀子苷和龙胆苦苷的含量

目的建立小儿清热片中栀子苷和龙胆苦苷的含量测定方法。方法采用反相高效液相色谱法(RPHPLC),Diamonsil C18柱,甲醇-0.1%磷酸水溶液(21:79)为流动相,流速1.0 m L/min,检测波长254 nm,柱温为室温。结果栀子苷在6.32~126.4μg/m L范围内线性关系良好(r=0.9998),平均回收率为100.9%,方法精密度(RSD)为0.76%(n=6);龙胆苦苷在2.04~40.8μg/m L范围内线性关系良好(r=0.9997),平均回收率为100.1%,RSD为0.84%(n=6)。结论该法可用于小儿清热片中栀子苷和龙胆苦苷的含量测定。     

响应曲面法优化栀子苷保健果冻的研究

在单因素试验的基础上,利用Box-Behnken试验设计模型和响应面分析方法,分别以栀子苷提取率、果冻感官评分作为指标,针对栀子苷的提取工艺和栀子苷保健果冻制备工艺进行双优化,以期制得一款色泽诱人、口感光滑细腻,且具有一定保健功效的果冻。结果表明,栀子苷最佳提取工艺的条件为：提取时间3.00 h,提取温度75.00℃,栀子粉末与乙酸乙酯的料液比1∶5.00（g/mL）,提取率为5.81%。综合感官评分得出栀子苷保健果冻的最优配方为：琼脂粉与水的料液比1∶52.00（g/mL）,栀子苷提取液添加量5.00%,木糖醇添加量8.00%。该条件下制得的栀子苷保健果冻呈半透明淡黄色、质地均匀、口感光滑细腻,具有栀子特有的香气。     

碱水解栀子苷大孔树脂分离纯化京尼平苷酸

目的:研究NaOH水解栀子苷,大孔树脂分离纯化京尼平苷酸的工艺。方法:用NaOH将栀子苷水解制备京尼平苷酸,并通过高效液相色谱法监测栀子苷的水解过程;比较7种大孔吸附树脂对京尼平苷酸的静态吸附和解析性能,筛选出一种吸附和解析性能较好的树脂,用动态柱层析法对京尼平苷酸进行分离纯化。结果:H103大孔树脂对京尼平苷酸的吸附和解析性能较好,动态吸附上样后用蒸馏水冲洗2 BV,再用30%乙醇洗脱2 BV,洗脱率达到95.2%,洗脱液真空干燥得到灰白色粉末,HPLC检测其纯度达96.1%。结论:采用碱水解栀子苷再用大孔树脂分离纯化京尼平苷酸,该工艺具有步骤少、收率高等优点,为京尼平苷酸的制备提供了一种新途径。     

反相HPLC法测定小儿退热口服液中栀子苷的含量

目的研究用HPLC法测定小儿退热口服液中栀子苷的含量。方法采用XTerraC18柱，以乙腈-水（12：88）为流动相，检测波长238nm，流速1．0mL·min^-1。结果栀子苷在63．12-631．2ng范围内线性关系良好，r=0．9999，平均加样回收率为98．7％。结论该方法操作简便可靠，结果准确、灵敏度高，重现性好，可作为控制该产品质量的方法。     

栀子油渣的有效成分分析

正本文对栀子果和经榨油工艺的栀子油渣进行分析,比较了京尼平苷酸、山栀子苷B、绿原酸、栀子苷、西红花苷I、西红花苷Ⅱ和西红花酸7种物质成分的含量变化。结果表明:与栀子果相比,栀子油渣中的西红花苷I、西红花苷Ⅱ有所降低,栀子苷有所增高。可以进行以栀子苷为主的综合开发利用,为进一步综合利用栀子的研究提供理论依据。随着人民生活水平的不断提高,对食用油的质量有了很高的要求,栀     

中等纯度栀子苷的纯化和制备工艺研究

以树脂法分离富集栀子黄色素后的栀子苷粗提液为研究对象,探讨两步吸附树脂法分离纯化栀子苷的制备工艺。考察栀子苷在12种大孔吸附树脂中的静态吸附和解吸性能,并采用吸附动力学模型和颗粒内扩散模型对吸附过程进行预测性拟合。在此基础上选择非极性树脂X-5研究栀子苷的动态纯化,探索不同pH和不同浓度洗脱剂对栀子苷纯化的影响。结果表明:一级吸附动力学Lagergren方程能很好地拟合栀子苷的吸附过程,颗粒扩散是影响栀子苷吸附效果的主要作用因素,饱和吸附量为8.2mg/g(栀子苷/X-5树脂),进一步精制的优化条件为pH 5.5,20%乙醇洗脱。经3次重复性扩大验证实验,洗脱产物中栀子苷纯度可达65.4%,回收率92.3%。大孔树脂分离纯化栀子苷的优化工艺对规模化制备中等纯度的栀子苷及重结晶单体生产提供了科学基础和实验依据。     

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.