叶黄素酯和叶黄素抗氧化作用比较

目的:研究叶黄素酯和叶黄素的抗氧化作用.方法:采用不同工艺制备叶黄素酯和叶黄素,通过体外还原能力试验及清除超氧阴离子自由基(O2·-)和羟基自由基(0H·)试验,测定并比较它们的抗氧化活性.结果:在还原能力试验中,叶黄素、叶黄素酯的还原能力远高于同浓度的VE,叶黄素的还原能力略高于叶黄素酯:在清除0H·和O2·-试验中,叶黄素酯和叶黄素的清除能力略高于BHT和VE,叶黄素酯清除0H·的能力略强于叶黄素,50%清除浓度EC50分别为0.88、1.36 mg/100 mL;叶黄素酯和叶黄素清除O2·-的EC50值基本相同,50%清除浓度EC50分别为1.11、1.07mg/100mL.结论:叶黄素和叶黄素酯都具有较强的清除自由基能力和抗氧化活性.叶黄素酯的光热稳定性强于叶黄素的.     

梅花鹿胎盘多肽体外抗氧自由基及抗油脂氧化性能的研究

研究了鹿胎盘多肽的抗氧化性.鹿胎盘多肽具有清除羟基自由基(·OH)、超氧自由基(O2-·)和H2O2的能力,同时时油脂有一定的抗氧化作用.随着多肽浓度的增大,抗氧化能力进一步增强.当鹿胎盘多肽浓度达到200μg/mL时,对·OH、O2,'->·、H2O2的抑制率分别为42.4%、73.7%、65.2%.在猪油贮藏的第7d,加入200、300μL浓度为200μg/mL的鹿胎盘多肽,其抗氧化作用比0.02%的BHT分别高28.83%、33.95%.     

菠菜色素蛋白复合物的抗氧化性研究

从菠菜叶中以硫酸铵沉降方式提取色素蛋白复合物,分析复合物中的主要功能成分,并以VC、BHT为对照,以总抗氧化能力和DPPH、·OH及O2-·等自由基的清除能力及亚油酸体系的抗氧化作用为指标,研究色素蛋白复合物的抗氧化能力及色素蛋白复合物与VC或BHT之间的相互作用.结果表明,在水相体系中复合物的总抗氧化能力为12.83 μ/mg复合物,与BHT相当,明显低于VC,当复合物浓度在10 μg/mL～500μg/mL时,对DPPH、·OH及O2-·等自由基的最大清除能力强于VC和BHT,分别为81.97％,88.14％和83.36％;以不同比例对复合物与VC或BHT进行复配,总浓度为100 μg/mL,与相同浓度色素蛋白复合物、VC或BHT单独作用时清除能力相比,发现VC与复合物之间存在协同增效作用,BHT无此效果.     

樱桃叶黄酮的体外抗氧化活性

考察樱桃叶黄酮的体外抗氧化活性,为樱桃叶黄酮在医药、食品方面的应用提供理论依据。从樱桃叶中提取黄酮,体外检测樱桃叶黄酮对羟自由基(·OH)和超氧阴离子自由基(O2-·)的清除作用,以及对H2O2诱发小鼠红细胞氧化溶血和肝脂质过氧化反应的抑制作用。结果显示,樱桃叶黄酮对·OH和O2-·具有清除作用,且呈现质量浓度依赖性,30μg/mL的黄酮溶液对·OH和O2-·的清除率分别达到85.67%和72.45%,并且对·OH的清除能力优于维生素C;樱桃叶黄酮对肝匀浆脂质过氧化反应和过氧化氢(H2O2)诱发红细胞氧化溶血具有抑制作用,当终质量浓度为30μg/mL时,抑制率分别为79.82%和75.54%。表明樱桃叶黄酮具有质量浓度依赖性的体外抗氧化活性。     

酸水解法提取酸浆果结合酚工艺及抗氧化活性

以酸浆果为试材,研究H2SO4体积浓度、液料比、水解时间、提取温度对酸浆果结合酚得率的影响及结合酚体外抗氧化能力。采用中心组合设计优化结合酚提取工艺,通过·OH、ABTS^+·及FRAP法评价结合酚体外抗氧化能力。结果表明,酸浆果结合酚最佳提取工艺为:H2SO4浓度5%,液料比55︰1 mL/g,水解时间16 h,提取温度45℃。此条件下提取得到的结合酚含量8.83±0.18 mg/g。酸浆果结合酚还原铁能力与BHT相当,比VC强,酸浆果游离酚原铁能力介于BHT与VC间(p<0.01);酸浆果结合酚、游离酚都有一定的ABTS^+·清除能力,都比VC、BHT清除能力弱(p<0.01),对·OH基团表现出一定还原能力,均比VC、BHT清除能力弱(p<0.01)。研究为酸浆果结合酚开发和利用提供依据,避免资源浪费。     

流动注射化学发光测定苹果多酚抗氧化活性

用流动注射化学发光法测定苹果多酚的体外抗氧化作用。将苹果多酚提取液加入3种化学发光体系,测量其发光强度,根据系统化学发光被抑制的程度评价苹果多酚对活性氧自由基的清除能力,并以抗坏血酸(VC)为阳性对照。结果表明,苹果多酚对三种活性氧自由基(O2-·、·OH、H2O2)的清除能力远强于VC;对H2O2和·OH的清除能力相当,强于对O2-·的清除能力。结果显示苹果多酚具有很好的抗氧化能力。     

襄荷乙醇提取物的体外抗氧化活性研究

目的:研究襄荷乙醇提取物(extract of Zingiber mioga Rose,EZR)的体外抗氧化作用.方法:用50%乙醇制备襄荷提取物,以V0作为阳性对照,测定EZR的总还原力及清除DPPH自由基的能力,并用荧光化学发光法测定了EZR对活性氧自由基(O2-·、·OH、H2O2)的清除能力.结果:EZR的总还原力为40.17±1.04mg Vc/g,在实验浓度范围内,对DPPH·、·OH、O2-·、H2O2的清除率分别达到了70%、64%、77%、71%.结论:EZR具有明显的体外抗氧化活性,但其抗氧化能力小于Vc.     

槐角黄酮的体外抗氧化活性研究

选用回流法提取槐角中黄酮类化合物,采用DPPH·法、邻苯三酚自氧化法和邻二氮菲法,测定了槐角黄酮对DPPH·、O2-·、·OH的清除率,并与维生素C(VC)比较,进行槐角黄酮的体外抗氧化活性研究.结果表明,槐角黄酮具有一定的抗氧化能力,在一定浓度范围内,清除自由基能力与其浓度呈正相关性.与阳性对照VC相比,槐角黄酮对DPPH·的清除作用较弱,IC50为0.0192mg/mL;而对O2-、、·OH的清除作用较强,IC50分别为0.0127、0.0160mg/mL.这表明槐角黄酮具有一定的抗氧化能力.     

水栒子果肉黄酮的体外抗氧化活性研究

以水栒子果肉总黄酮的粗提物为原料,测定其体外抗氧化能力。利用匀浆法提取水栒子果肉黄酮,比色法测定其含量。采用1,1-二苯基-2-三硝基苯肼（DPPH）自由基清除法、2,2-吖嗪双（3-乙基-7-苯并噻唑啉磺酸）二铵盐（ABTS）自由基清除法、超氧阴离子自由基清除法（SRSA）、还原能力测定法和铁离子还原/抗氧化能力法（FRAP）,对其进行体外抗氧化活性研究。结果表明,水栒子果肉总黄酮的自由基清除能力和还原能力随总黄酮浓度的升高而增强,DPPH自由基清除能力和超氧阴离子自由基（O-2·）清除能力与特丁基对苯二酚（TBHQ）相当,高于丁基羟基甲苯（BHT）、丁基羟基茴香醚（BHA）、VC、VE;ABTS清除能力高于BHT、VC、VE,略低于TBHQ和BHA;还原能力与TBHQ相当,高于BHT、VE,略低于BHA和VC;铁还原能力与TBHQ相当,高于BHT、VC、VE,低于BHA。水栒子果肉黄酮有较强的体外抗氧化能力,具有很好的开发潜力。     

紫薯花青素体外抗氧化及对H2O2诱导HepG2细胞氧化损伤的保护作用

目的：研究紫薯花青素的体外抗氧化作用,建立H2O2诱导HepG2细胞氧化损伤模型,初步评价紫薯花青素的抗氧化应激作用。方法：紫薯干粉经过提取、纯化制得紫薯花青素干粉,分别测定紫薯花青素的总还原力、对羟自由基（·OH）、超氧阴离子自由基（O2－•）的清除能力以及对大鼠红细胞溶血的保护作用。建立H2O2诱导HepG2细胞氧化损伤模型,采用四甲基偶氮唑蓝（methyl thiazolyl tetrazolium,MTT）法检测不同质量浓度紫薯花青素对HepG2细胞氧化损伤的保护作用。结果：紫薯花青素的还原力和VC基本相当;紫薯花青素对·OH有很好的清除效果,在实验浓度范围内有明显的剂量-效应关系;随紫薯花青素浓度的升高,对O2－•的清除作用增强,呈现良好的量-效关系,单位浓度的紫薯花青素对O2－•的清除作用比2,6-二叔丁基-4-甲基苯酚（butylated hydroxytoluene,BHT）效果好。不同质量浓度的紫薯花青素均可抑制H2O2诱导的大鼠红细胞溶血,且随着紫薯花青素质量浓度的升高,大鼠红细胞的溶血度降低,呈现良好的量-效关系。H2O2诱导的HepG2细胞氧化损伤模型中,50～1 600 μg/mL的紫薯花青素均能够抑制H2O2引起的HepG2细胞凋亡,当紫薯花青素质量浓度达到800 μg/mL时,HepG2细胞存活率为（88.03±7.48）%。结论：紫薯花青素具有良好的体外抗氧化作用,并对H2O2诱导HepG2细胞氧化损伤具有明显的保护作用,研究初步揭示了紫薯花青素具有体外抗氧化作用。     

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