四种食品防腐剂对桔皮黄酮清除自由基影响

用90%的乙醇提取桔皮中的黄酮类化合物,通过DPPH法研究四种食品防腐剂在不同浓度和温度下对桔皮黄酮类化合物清除自由基能力的影响。结果表明,在温度40℃时,0.1%山梨酸、0.1%苯甲酸可以提高桔皮黄酮类化合物清除自由基的能力;0.1%丙酸钠、0.06%对羟基苯甲酸乙酯使桔皮黄酮类化合物清除自由基的能力下降。在温度60℃时,0.1%山梨酸、0.1%苯甲酸、0.06%对羟基苯甲酸乙酯使桔皮黄酮类化合物清除自由基的能力下降。0.1%丙酸钠对桔皮黄酮类化合物清除自由基能力的影响与温度没有关系。     

花椒黄酮类化合物提取液清除自由基作用研究

以花椒为原料,测定其黄酮类化合物对羟基自由基和超氧阴离子自由基清除能力。研究结果表明,花椒黄酮类化合物对自由基具有较强的清除能力,其清除羟基自由基和超氧阴离子自由基的有效半数浓度分别为0.39mg/mL和0.43mg/mL。     

金针菇黄酮类化合物的抗氧化性作用

通过邻苯三酚自氧化法,水杨酸法比色法分别测定金针菇的黄酮类化合物清除超氧阴离子自由基(.O2-)以及羟基自由基(.OH)的效果。结果表明,不同浓度的金针菇黄酮类化合物能显著地清除超氧阴离子自由基和羟基自由基,且随着金针菇黄酮类化合物浓度的升高其抗氧化性作用逐渐增强,并在一定浓度范围内黄酮化合物与抑制率呈正相关。     

杏仁皮中黄酮类化合物抗氧化性的研究

从清除超氧阴离子自由基、还原力、清除DPPH自由基、清除羟基自由基等方面,研究杏仁皮中黄酮类化合物的抗氧化性.结果表明,杏仁皮中黄酮类化合物的还原能力较强,对DPPH·自由基和羟基自由基有较强的清除能力,对Fe~(2+)的络合能力和脂质体过氧化反应的抑制作用也较强,但对超氧阴离子自由基的清除能力较弱.因此,杏仁皮中黄酮类化合物是一种抗氧化功效较强的活性物质,具有很好的保健功能.     

西瓜皮营养成分分析

以西瓜皮为试材,定量分析西瓜皮中的微量元素、VC和硝酸盐含量,并研究西瓜皮中黄酮类化合物对羟基自由基的清除作用.采用火焰原子吸收光谱法对西瓜皮中Ca、Na、Mg、Fe、Cu、Zn和Mn 7种微量元素进行分析测定;利用邻二氮菲-Fe2+氧化法对西瓜皮中提取物清除羟基自由基作用的效果进行科学研究,结果表明:西瓜皮中富含对人体有益的微量元素,且VC含量较高,硝酸盐含量符合国家卫生标准.西瓜皮提取物对羟基自由基有明显的清除作用,清除率与黄酮含量呈正相关.     

油菜蜂花粉中黄酮类物质清除羟基自由基的研究

自由基是人体过早衰老的主要原因之一,本文利用油菜蜂花粉提取液中的功能成分黄酮类化合物对羟基自由基的清除作用进行了研究,结果表明,油菜蜂花粉中的黄酮类化合物对羟基自由基有着较好的清除效率,在12.5～100μg/ml的范围内浓度与清除效率呈线性关系。     

襄荷中黄酮类化合物的抗氧化性研究

以襄荷为原料,利用超声波辅助乙醇法提取襄荷中的黄酮类化合物。通过测定DPPH自由基清除率、超氧阴离子清除率、羟基自由基清除率及其在菜籽油中的过氧化值(POV)评价襄荷花苞中黄酮类化合物的抗氧化活性。结果证明,襄荷花苞中黄酮类化合物有一定的清除DPPH·、O_2~—·和羟基自由基的能力,当襄荷花苞黄酮提取液浓度达到0.705 mg/mL时,其对DPPH·和超氧阴离子清除率分别达到98.7%和99.3%,与提取液质量浓度成正比。在菜籽油中与Vc具有协同作用,且抗氧化能力与襄荷花苞中黄酮类化合物含量呈正比。     

金莲花中黄酮类化合物抗氧化能力的研究

采用微波法提取金莲花中黄酮类化合物,并采用HPD-300大孔树脂对粗提液进行精制,精制物中黄酮含量比粗提物中黄酮含量明显提高.在自由基清除试验中,精制金莲花黄酮类化合物表现出较强的自由基清除能力,并且精制后的金莲花黄酮类化合物自由基清除能力高于未精制的产品,精制物对自由基的清除效果接近抗坏血酸的作用效果.     

黑花生衣中黄酮类物质的提取方法研究

研究超声波辅助提取黑花生衣中黄酮类化合物的工艺条件,探讨乙醇浓度、料液比、提取时间、提取温度、pH对提取效果的影响。确定影响黄酮提取效果的最主要因素是料液比,并得出黑花生衣中黄酮类化合物在超声波频率为50 kHz条件下提取的最佳工艺条件为:提取溶剂为60%乙醇,提取时间45 min,提取温度40℃,料液比1∶300(g/mL),pH2.5。在此基础上,通过测定黑花生衣提取液对活性自由基的清除作用,探讨其抗氧化活性。结果表明,黑花生衣中黄酮类化合物对羟基自由基(·OH)、和DPPH·自由基皆具有显著的清除作用,且其清除作用与浓度之间呈量效关系。     

马齿苋黄酮提取液抗氧化活性的初步研究

采用浓度为75%的乙醇提取马齿苋中的总黄酮物质,结合柱层析法和分光光度法,测其总黄酮的含量为7.64%.研究马齿苋中黄酮类化合物对超氧自由基、羟基自由基的清除作用.结果表明:马齿苋中黄酮类化合物对清除自由基有明显的作用,黄酮类化合物的加入量在试验范围内与其抗氧化性呈正相关关系.在相同奈件下,其抗氧化性优于抗坏血酸、芦丁和β-胡萝卜素,表明黄酮类物质是一种很有潜力的天然、安全、高效的抗氧化剂,研究结果可为利用马齿苋生产黄酮类药用成分提供科学依据.     

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.     

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