不同分子量红花籽抗氧化肽稳定性研究

目的:研究不同分子量红花籽蛋白抗氧化肽活性的稳定性。方法:以脱壳红花籽粕为实验材料,经复合酶酶解分离制备抗氧化肽,以1,1-二苯基-2-三硝基苯肼（1-diphenyl-2-trinitrophenylhydrazine,DPPH）自由基、超氧阴离子自由基（superoxide anion radical,O₂?·）及羟自由基（hydroxyl free radicals,·OH）清除能力为指标,探讨温度、pH、食品原辅料、金属离子及模拟胃肠消化等环境因素对不同分子量红花籽抗氧化肽活性的影响。结果:红花籽蛋白酶解物<3 kDa（SSPH-Ⅰ）、3~5 kDa（SSPH-Ⅱ）较分离前活性显著增加（P<0.05）,SSPH-Ⅲ（5~10 kDa）和SSPH-Ⅳ（>10 kDa）较分离前活性显著降低（P<0.05）,选取活性显著增加组分研究发现SSPH-Ⅰ抗氧化活性更加稳定,能在60~121 ℃高温、pH6~8弱酸弱碱条件下保持活性,各自由基清除率维持率达到90%以上,10 g/100 mL NaCl和葡萄糖、0.2 g/100 mL柠檬酸对SSPH-Ⅰ抗氧化活性有增强协同作用,各自由基清除率维持率增加至105%左右,10 g/100 mL的蔗糖和0.2 g/100 mL的防腐剂对活性影响不大,添加Cu2+、Zn2+和K+金属离子对SSPH-Ⅰ抗氧化稳定性显著下降（P<0.05）,其影响顺序为:Cu2+>Zn2+>K+>Mg2+>Ca2+,经模拟胃肠消化后活性较稳定,维持率为80%。结论:筛选得到<3 kDa红花籽蛋白抗氧化肽组分活性较高且稳定,为其工业化生产及应用提供理论依据。     

长白山榛子抗氧化肽制备及其活性研究

以长白山榛子分离蛋白为原料,采用碱性蛋白酶制备抗氧化肽,通过Box-Behnken中心组合试验确定最佳水解工艺条件为:酶解温度50℃、加酶量8 000 U/g、底物浓度5.0%、pH9.5。对该条件制备的抗氧化肽进行活性研究,结果显示随着浓度的升高,榛子抗氧化肽在4 mg/mL时对ABTS自由基和DPPH清除率均达到100%,8 mg/mL时对·OH清除率和总还原能力分别达到85.46%和0.859,12 mg/mL时,对Fe~(2+)螯合率达到99.3%。     

添加物和体外模拟胃肠道消化对鸢乌贼抗氧化肽稳定性的影响

以鸢乌贼抗氧化肽为研究对象,以DPPH自由基、羟自由基(·OH)清除能力和还原力为评价指标,探究了蔗糖、海藻糖、柠檬酸、NaCl、防腐剂、金属离子以及人工模拟胃肠道消化对其抗氧化活性的影响。结果表明:蔗糖和海藻糖对鸢乌贼抗氧化肽的抗氧化活性无显著性改变;柠檬酸和NaCl在一定的浓度范围内能起到增效作用,使鸢乌贼抗氧化肽的抗氧化活性增加;防腐剂(山梨酸钾和苯甲酸钠)对鸢乌贼抗氧化肽的抗氧化稳定性影响不明显;Cu~(2+)、Zn~(2+)使鸢乌贼抗氧化肽的抗氧化活性随着浓度增加显著性降低,Mg~(2+)、Ca~(2+)和K~+对鸢乌贼抗氧化肽的抗氧化活性影响较小;而人工模拟胃肠道消化表明,胃肠道消化不利于保持鸢乌贼抗氧化肽的抗氧化稳定性。     

长白山松子抗氧化肽制备及活性研究

以长白山松子分离蛋白为原料,采用碱性蛋白酶制备抗氧化肽,通过Box-Behnken中心组合试验确定最佳水解工艺条件为:酶解温度56.5℃、加酶量7822U/g、底物质量浓度0.021g/mL、pH9.0、酶解时间240min。对该条件制备的抗氧化肽进行活性研究,结果显示随着浓度的升高,松子抗氧化肽在4mg/mL时对ABTS自由基的清除率和Fe2+螯合率达到100%,16mg/mL时对DPPH自由基清除率达到80.95%,24mg/mL时,对羟基自由基清除率达到100%。     

菜籽抗氧化肽WDHHAPQLR的环境稳定性研究

本实验以DPPH·自由基清除活性、Fe~(2+)-螯合金属离子能力为指标来考察温度、酸碱度、食品配料成分、金属离子、防腐剂和人工胃肠液等环境因素对菜籽抗氧化肽(WDHHAPQLR)稳定性的影响。结果表明:随着温度的升高,抗氧化肽的活性逐渐降低,但还是保持在较高水平,但是当温度高于60℃时,菜籽抗氧化肽的活性显著降低,温度为100℃时,Fe~(2+)-螯合金属离子能力活性保持率仅在30%左右。强酸和强碱环境对抗氧化肽的稳定性影响较大,当溶液的pH值在6.0～8.0范围内时,活性较为稳定。抗氧化肽溶液的活性随着食盐浓度的增大而有所降低,当食盐的浓度达到8%时,抗氧化肽的活性保持率为86.33%。蔗糖质量分数在2%～8%范围内时,菜籽抗氧化肽的活性随蔗糖含量的增加而显著下降,在蔗糖质量分数达到8%,活性保持率在80%以上。在0.02%～0.16%质量分数范围内,柠檬酸对菜籽抗氧化肽的活性影响不大,其活性保持率均在90%以上。常见的金属离子对菜籽抗氧化肽的稳定性影响不一,Cu~(2+)和Zn~+对菜籽抗氧化肽的DPPH·自由基清除活性和亚铁离子螯合能力的影响最为显著。苯甲酸钠和山梨酸钾对抗氧化肽的稳定性影响不明显,可以在多肽产品中作为防腐剂使用;菜籽抗氧化肽溶液经过胃蛋白酶消化后抗氧化活性显著增加,再经过胰蛋白酶消化后活性大幅度下降。     

酶解缫丝蚕蛹蛋白抗氧化肽的分离与稳定性研究

目的：研究酶解缫丝蚕蛹蛋白抗氧化肽的分离和稳定性,为其开发应用提供基础数据。方法：超滤分离酶解缫丝蚕蛹蛋白抗氧化肽,比色法测定其抗氧化能力。结果：超滤分级后得到分子质量为200～3 000 D的酶解缫丝蚕蛹蛋白抗氧化肽对O2－•、•OH、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基的IC50分别为18.85 mg/mL、3.13 mg/mL、35.23 μg/mL。该抗氧化肽经过4 h胃蛋白酶+胰蛋白酶处理前后对DPPH自由基清除率分别为81.05%、82.26%;在pH 4、8条件下处理1 h,对DPPH自由基清除率分别为98.02%、11.80%（100 μg/mL）;在温度95 ℃条件下处理1 h,对DPPH自由基清除率为87.11%（100 μg/mL）;用浓度为1.0 mol/L的NaCl处理6 h,相比对照组,对DPPH自由基清除率由51.58%下降到22.68%（60 μg/mL）。结论：超滤后得到的分子质量为200～3 000 D的酶解缫丝蚕蛹蛋白抗氧化肽的抗氧化能力比酶解原液有一定提高;且在酸性、高温、脱盐处理后对DPPH自由基的清除能力保持较好;胃肠道消化酶对其DPPH自由基清除能力的影响不显著（P＞0.05）。     

芝麻蛋白制备金属螯合肽的酶解工艺研究

分别采用木瓜蛋白酶、胰蛋白酶和碱性蛋白酶Alcalase对芝麻蛋白进行水解,结果表明胰蛋白酶为制备金属螯合肽的最佳酶。通过优化胰蛋白酶酶解工艺条件发现最佳条件为:底物质量浓度5%(g/100mL),酶添加浓度20u/g(底物),水解时间5h,得到的酶解产物金属螯合率最强,与Fe2+的螯合率为90.9%,与Zn2+的螯合率为93.5%。通过考察水解度对酶解产物金属螯合率及抗氧化能力的影响,结果显示水解度在18.9%到22.4%之间的酶解产物金属螯合率强,且水解度在一定范围内金属螯合率和抗氧化能力均与水解度呈正相关性。     

基于偏最小二乘回归模型的鱼露理化成分与抗氧化活性关系研究

为探究影响鱼露抗氧化活性的关键成分，研究不同发酵时期鱼露的抗氧化活性与理化成分（可溶性肽、游离氨基酸和有机酸），进行相关性分析，构建偏最小二乘回归模型。结果表明，发酵6个月鱼露DPPH清除活性、还原力、总酚含量最高，分别为85.4%,0.499和38.4μg GAE/mL；发酵12个月鱼露理化物质最丰富，富含丰富的TCA可溶性肽（5.81 g/100 mL）、游离氨基酸、乳酸（9.87 mg/100 m L）、柠檬酸（0.56 mg/100 m L）、琥珀酸（9.20 mg/100 m L）。由PLSR模型可知，半胱氨酸、酪氨酸、脯氨酸、柠檬酸是影响鱼露抗氧化活性的关键成分，半胱氨酸、酪氨酸、脯氨酸对抗氧化活性有积极作用，而柠檬酸起到相反的作用。研究为数学模型在鱼露抗氧化活性分析中的应用提供依据。     

细点圆趾蟹含肉下脚料酶解物中抗氧化肽的分离与鉴定

目的：从细点圆趾蟹含肉下脚料的胰蛋白酶酶解产物中分离鉴定具有高ABTS+·清除率的抗氧化肽。方法：通过超滤系统、Sephadex G-15和半制备型RP-HPLC,从细点圆趾蟹含肉下脚料酶解产物中分离制备抗氧化肽,用超高效液相色谱-电喷雾飞行时间串联质谱（UPLC-ESI-TOF-MS/MS）对肽的结构进行表征,再通过合成肽对其结构与ABTS+·清除率进行验证。结果：获得2个ABTS+·清除能力较强的抗氧化肽,其氨基酸序列分别为Tyr-Glu-Gly（YEG）和Tyr-Glu（YE）。合成肽YEG和YE的分子质量分别为367.35 u和310.30 u,纯度分别为98.52%和98.04%,清除ABTS+·的IC50值分别为0.456 mg/mL和0.184 mg/mL,且YE的IC50值比L-还原型谷胱甘肽高30.30%。结论：细点圆趾蟹含肉下脚料的胰蛋白酶酶解产物含有抗氧化活性的肽类成分,为其抗氧化肽的开发提供理论依据。     

艾叶水提物和酸提物的抗氧化及抗菌活性比较

为比较研究艾叶水提物和酸提物抗氧化及抗菌的作用。分别采用去离子水和柠檬酸溶液提取艾叶,得到两种提取物,测各自的总黄酮、总多酚和多糖含量;通过DPPH自由基、羟自由基及ABTS自由基来评价提取物的抗氧化能力;利用牛津杯法测定提取物的抑菌活性,并探讨其抑菌机制。结果表明：艾叶水提物中总黄酮、总多酚及多糖含量分别为208.03、51.77和398.72 mg/g,艾叶酸提物分别为80.39、25.44和453.45 mg/g。在一定浓度范围内,艾叶水提物和艾叶酸提物均有较强抗氧化能力,对DPPH自由基清除率的半数抑制浓度（median inhibition concentration,IC50）分别为33.10和54.52 μg/mL;对羟自由基清除率的IC50值分别为2.92和1.63 mg/mL;对ABTS自由基清除率的IC50值分别为0.17和0.32 mg/mL。艾叶水提物无明显抑菌效果;但艾叶酸提物对金黄色葡萄球菌、志贺氏菌、沙门氏菌具有显著抑菌活性,最小抑菌浓度分别为0.10、0.10和0.20 g/mL。通过测定抑菌动力学、细胞膜通透性实验证实酸提物能有效抑制致病菌生长、改变细胞膜通透性;扫描电镜和聚丙烯酰胺凝胶电泳证实酸提物能破坏细菌细胞壁形态、抑制细菌的蛋白质合成。柠檬酸溶液提取法比水提法更适用于艾叶活性成分的提取,艾叶酸提物更具有食品防腐剂和抗氧化剂的潜力。     

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