超声波辅助法提取锦灯笼宿萼中的木犀草素

以锦灯笼宿萼为原料,优化其木犀草素的超声提取工艺。在单因素试验的基础上,采用正交试验法,考察乙醇浓度、料液比、超声次数、超声时间对锦灯笼宿萼干浸膏中木犀草素含量的影响。结果表明,锦灯笼宿萼中木犀草素的最佳超声提取工艺条件为乙醇浓度75%、料液比1∶20(m∶V)、超声3次、超声时间每次30min,在该条件下干浸膏中木犀草素含量为2.175mg/g。该提取方法具有操作简单、提取时间短等优点,适用于锦灯笼宿萼中木犀草素的提取。     

微波-超声辅助提取玉米须木犀草素的工艺优化

目的探究微波-超声辅助提取玉米须中木犀草素的工艺条件。方法以木犀草素得率为评价指标,考察液料比、乙醇浓度、超声温度、微波时间对木犀草素得率的影响,在单因素试验的基础上,采用Box-Benhnken试验设计优化玉米须木犀草素的提取工艺,并建立相应的回归模型。结果玉米须中木犀草素的最佳提取条件如下:液料比为28 m L/g,乙醇浓度为74%,超声温度为58℃,微波时间为49 s;各因素对木犀草素得率的影响大小顺序为乙醇浓度超声温度液料比微波时间。通过3次验证试验,玉米须中木犀草素的得率为(0.101±0.001)%,实际测定值与理论预测值的相对误差为?1.94%。结论该研究获得了玉米须中木犀草素的最佳提取工艺,为玉米须中木犀草素的开发提供参考。     

连续萃取法从花生壳中提取木犀草素的研究

天然黄酮类化合物木犀草素具有抗氧化、抗菌、抗炎、抗癌、心血管保护及神经保护等多种生物活性。以花生壳为原料,采用连续萃取法从花生壳中提取木犀草素,进行工艺优化,并采用高效液相色谱法进行含量测定。结果显示,花生壳中木犀草素的最佳提取工艺条件为：采用石油醚对花生壳进行脱脂预处理,萃取剂为75%乙醇溶液,料液比为1∶20（g/mL）,萃取温度80℃,萃取时间2.0 h,此时木犀草素的提取率可达到0.32 mg/g,纯度为67.86%。连续萃取法从花生壳中提取木犀草素,节省溶剂,操作简单,提取率高。     

花生壳中木犀草素的微波辅助提取工艺研究

研究微波辅助提取花生壳中木犀草素的最佳工艺条件.采用HPLC法测定木犀草素含量,以提取率为指标,应用单因素和正交试验,分别考察微波辅助提取时间、料液比、提取时间等3个因素影响,并将筛选工艺与目前文献的乙醇提工艺进行对比分析.结果表明,微波辅助提取木犀草素的最佳工艺条件:微波时间为2.0min,料液比为1∶6,提取时间为4h.与传统乙醇提取工艺相比,微波辅助提取工艺提取花生壳中木犀草素的提取率提高了4.53倍.     

乌蔹莓中木犀草素的提取工艺研究

确定乌蔹莓中木犀草素的最佳提取工艺.对影响木犀草素提取率的主要因素(乙醇的浓度、提取温度、料液比、提取时间等)进行试验,并通过单因素和正交试验确定最佳提取工艺.最终的提取工艺为最佳的提取工艺条件为:70%乙醇(体积比),料液比为1:14(g/L),提取温度为75℃,提取2次每次提取3h.该提取工艺高效稳定,可用于乌蔹莓中木犀草素的提取.     

花生壳中木犀草素的超临界CO2萃取工艺研究

目的:研究超临界CO2萃取花生壳中木犀草素的最佳工艺条件。方法:采用HPLC法测定木犀草素含量,以提取率为指标,应用单因素和正交实验,分别考察萃取温度、萃取压力、分离温度、分离压力以及CO2流量等5个因素影响,并将筛选工艺与目前文献的乙醇提工艺进行对比分析。结果:超临界CO2萃取木犀草素的最佳工艺条件:萃取温度为50℃,萃取压力为35MPa,分离温度为30℃,分离压力为10MPa,CO2流量为7L/h。结论:与传统乙醇提取工艺相比,超临界CO2萃取工艺提取花生壳中木犀草素的提取率提高了2.63倍。     

祁菊有效成分微波辅助水提工艺研究

祁菊微波水提工艺的优化,采取L9(34)正交优化试验,以祁菊总黄酮及木犀草苷提取率为指标,水为溶剂,考察料液比、提取时间和提取温度等因素对提取率的影响,并与水回流法进行比较。结果表明,最佳提取工艺条件为提取时间3min、料液比1:25、提取温度85℃、提取2次,此条件下总黄酮和木犀草苷提取率分别为65.02%、85.77%;水回流法总黄酮、木犀草苷提取率分别为66.12%、85.37%。微波水提法可以在较短时间和较低温度下达到水回流下的提取率,从而获得一条高效率、经济安全的提取工艺路线。     

纸上荧光数码成像法快速测定花生壳中的木犀草素含量

本文利用木犀草素在乙二胺四乙酸二钠(EDTA)协同配合下可增强铽离子(Tb~(3+))荧光强度的特征,建立了一种快速测定木犀草素含量的纸上荧光数码成像法。将木犀草素溶液及EDTA、Tb~(3+)、Na OH等检测试剂点样于纸芯片的检测区,用智能手机在紫外灯下采集并读取荧光图片的红(R)、绿(G)、蓝(B)颜色数值,研究了该检测体系的显色条件、干扰物质、木犀草素浓度计算模型等。结果表明:优化后的显色条件为依次在纸芯片检测区加入0.4μL 1.0 mol/L NaOH溶液、1.0μL 1.0×10-2 mol/L EDTA溶液、6μL木犀草素标准溶液、0.75μL 1.5 mmol/L Tb~(3+)溶液,室温下反应5 min。在此条件下,木犀草素的浓度在0.05～4.0 mmol/L时与B/(R+G+B)成良好的线性关系,R2=0.9954;用该法测定花生壳中木犀草素含量时,回收率为96.5%～106.3%,相对标准偏差为3.9%。该法快速、简便、成本低廉,能用于复杂样品中木犀草素含量的现场测定。     

Ca2+螯合法纯化花生壳黄酮工艺研究

基于黄酮化合物与金属离子的螯合作用,以花生壳黄酮及木犀草素的含量为指标,研究了花生壳黄酮的纯化方法。结果表明,用Ca2+纯化花生壳黄酮的最优条件为黄酮粗提物溶液pH为9.0,CaCl2:黄酮粗提物质量比为1:10,黄酮粗提物初始浓度为10.0mg/mL。最佳条件下黄酮的含量从初始的11.0%提高到27.84%。经高效液相色谱分析,结果表明纯化前黄酮粗提物中木犀草素的含量为0.87%,经Ca2+螯合纯化后,木犀草素的含量提高到1.97%。     

酶法辅助提取花生壳中木犀草素的工艺研究

目的：研究纤维素酶法辅助提取花生壳中木犀草素的最佳工艺条件。方法：采用HPLC法测定木犀草素含量,以提取率为指标,分别考察料液比、加酶量、pH值、温度、时间对纤维素酶酶解反应的影响,并将筛选工艺与目前文献的乙醇直接提工艺进行对比分析。结果：纤维素酶酶解花生壳的最佳工艺条件：料液比为1∶8（w/v）、酶用量为25U/g药材的量、酶解pH值为4.8、酶解温度50℃、酶解时间为6h。结论：与传统乙醇直接提取工艺相比,酶法辅助提取工艺提取花生壳中木犀草素的提取率提高了2.15倍。     

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.