核桃花抗氧化活性研究

采用DPPH.清除法对民间食用蔬菜--新鲜核桃花提取物的体外自由基清除作用进行研究.结果表明,核桃花食用部位具有一定的抗氧化活性, 以乙酸乙酯提取物活性最好,活性强于BHA,IC50值达到30.7 μg.     

野生树头菜抗氧化活性

采用DPPH自由基清除法分别对云南民间食用植物树头菜乙醇、石油醚、乙酸乙酯、正丁醇和水提取物的体外自由基清除作用进行了研究,并应用TLC方法对它们的化学成分组成进行了比较。结果表明树头菜不同提取物对DPPH自由基清除作用差别较大,树头菜抗氧化活性主要集中在正丁醇和乙酸乙酯提取物部分I,C50值分别为43.7,42.2μg/mL,活性十分接近,主要是中等极性和皂苷类化合物,但远较BHA和VC弱,自由基清除作用比较弱。     

荞麦新芽蔬菜提取物的抗氧化作用研究

以荞麦新芽蔬菜为研究对象,利用比色法和发光化学法测定了荞麦新芽蔬菜提取物对DPPH自由基、羟基自由基及超氧自由基的清除效果.结果表明,荞麦新芽蔬菜提取物对DPPH自由基、羟基自由基具有很强清除作用,而对超氧自由基的清除能力较弱.其清除DpPH的IC50值为0.064mg/mL,当荞麦新芽蔬菜乙醇提取物浓度为0.15mg/mL时,羟自由基清除率达57.65%.     

秦岭山脉野生蒲公英提取物的抗氧化活性及其对胡麻油氧化稳定性的影响

以秦岭山脉野生蒲公英全草为原料,采用超声波纤维素酶同步法提取总活性成分。对蒲公英提取物的DPPH自由基清除能力、超氧阴离子自由基清除能力、羟自由基清除能力和总还原能力进行了测定,并与人工合成VC进行了比较,同时采用加速氧化的方法评价蒲公英提取物对胡麻油氧化稳定性的影响,并与BHT、迷迭香提取物进行比较。结果表明:蒲公英提取物比人工合成VC有更高的抗氧化活性; 3种抗氧化剂抗氧化能力大小为迷迭香提取物(700 mg/kg)蒲公英提取物(700 mg/kg) BHT(200 mg/kg),并且蒲公英提取物添加量与胡麻油的氧化稳定性呈正相关。因此,秦岭山脉野生蒲公英全草总活性成分提取物可作为天然抗氧化剂用于延缓食用油氧化。     

麻疯树籽仁/壳乙醇提取物的体外抗氧化活性北大核心CSCD

为了提高麻疯树种子的开发利用价值,采用体外抗氧化实验对麻疯树籽仁/壳乙醇提取物抗氧化活性进行了研究。分别以麻疯树种子中的籽仁和籽壳为原料,经75%乙醇提取,在对提取物主要成分进行分析的基础上,以V为阳性对照,测定两种提取物对自由基(DPPH自由基、ABTS~+自由基、羟自由基和超氧自由基)的清除能力、还原能力以及抑制亚油酸自氧化能力。结果表明:麻疯树籽仁/壳乙醇提取物中多糖类物质总含量分别为47.67%和52.21%,酮类物质总含量分别为0.774%和4.22%,麻疯树籽壳乙醇提取物中还含有0.30%的多酚类物质;麻疯树籽仁/壳乙醇提取物均具有一定的抗氧化活性,其中籽壳乙醇提取物对DPPH自由基、ABTS~+自由基、羟自由基、超氧自由基的清除效果较好;麻疯树籽仁/壳乙醇提取物的还原能力和对亚油酸自氧化的抑制能力相对较弱。麻疯树籽壳乙醇提取物的抗氧化活性优于籽仁乙醇提取物,可能与籽壳乙醇提取物中含有较多的黄酮类和多酚类物质有关。     

野生蔬菜苦凉菜抗氧化活性

采用DPPH自由基清除法对民间食用植物苦凉菜提取物的体外自由基清除作用进行研究.结果表明:苦凉菜不同提取物对DPPH自由基清除作用差别较大,乙醇提取物和乙酸乙酯提取物活性较好,但较BHA和Vc非常弱,没有抗氧化价值.     

粗壮女贞苦丁茶提取物的抗氧化活性研究

研究粗壮女贞苦丁茶提取物在不同试验体系及细胞和食品层面的抗氧化活性,为其在食品工业的高附加值开发利用提供理论基础。通过体外化学分析法系统测定提取物的自由基清除作用、脂质过氧化抑制效应及还原能力;分别以PC12细胞、花生油和猪油为模型,评价提取物对细胞氧化损伤及食用油脂氧化酸败的抑制效果。结果表明:粗壮女贞苦丁茶提取物具有较强的还原能力,可有效清除受试自由基,并抑制脂质过氧化反应的发生,具有优良的抗氧化活性;试验条件下,提取物可显著抑制并修复PC12细胞的氧化损伤,亦能有效延缓食用油脂的氧化酸败。     

7种食用真菌抗氧化活性研究

采用DPPH法、Fenton法和邻苯三酚自氧化法对7种食用真菌不同部位提取物的抗氧化活性进行研究。各种提取物对DPPH都具有一定的清除能力,其中姬菇菌柄、茶树菇菌盖和香菇菌盖的提取物较其他样品的清除效果强;对羟基自由基除茶树菇菌盖提取物有一定的清除能力,其余提取物的清除能力较弱;对超氧阴离子除茶树菇菌盖较强,茶树菇菌柄和香菇菌盖有一定的清除能力外,其余提取物的清除效果较弱。食用真菌不同部位提取物均具有一定的抗氧化活性,其中茶树菇菌盖综合抗氧活性最佳。     

甜菜树多糖的提取工艺优化及其体外抗氧化性评价

研究优化甜菜树多糖的提取工艺,并测定其多糖的抗氧化性。采用苯酚-浓硫酸法测定甜菜树多糖的含量,通过正交试验优化了多糖的提取工艺,以羟基自由基(·OH)、1,1-苯基-2-苦基肼自由基(DPPH·)和超氧阴离子自由基(O2-·)清除能力为指标,探究了甜菜树多糖的体外抗氧化活性。结果表明:多糖的最佳提取工艺参数为料液比1:50 g/m L、超声时间30 min、超声温度40℃,在此条件下多糖的平均提取率为2.70%。体外抗氧化活性结果表明,多糖对羟基自由基、DPPH自由基和超氧阴离子自由基的清除率可分别达到78.99%、75.65%和87.40%,说明多糖对·OH、DPPH·和O_2~-·有较强的清除能力。     

8种水生蔬菜清除水溶性ABTS+自由基活性研究

为评价水生蔬菜的抗氧化活性,采用超声破碎提取制备8种水生蔬菜的水提取物,研究提取物与ABTS~+自由基反应的紫外可见吸收光谱特征。结果表明,8种水生蔬菜提取物对ABTS~+自由基734 nm处吸收峰值随水生蔬菜用量增加呈剂量效应关系,相对于DPPH自由基清除试验基于517 nm处的吸收峰测量,ABTS~+自由基734 nm处吸收峰测量避免了水生蔬菜色素的光谱干扰,且ABTS~+自由基水溶性特点更适于日常饮食的抗氧剂摄入评价。8种水生蔬菜提取物的半数抑制浓度依次为:茭瓜(4.111 mg/mL)慈姑(2.932 mg/mL)荸荠(2.517 mg/mL)海菜(2.413 mg/mL)水芹菜(1.795 mg/mL)水芋(1.594 mg/mL)莲藕(0.974 mg/mL)水蕨菜(0.140 mg/mL),水蕨菜具有最强的自由基清除活性。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press