藤椒油体外抗氧化活性研究

以冷榨藤椒油和溶剂萃取的藤椒油为原料,采用体外抗氧化实验研究其抗氧化能力。以BHT和VC为阳性对照,通过测定两种藤椒油还原力、对·OH、DPPH·、O-2·清除率,探讨藤椒油的抗氧化能力。结果表明,冷榨油和溶剂油的还原能力随其质量浓度的增加而增强,对·OH、DPPH·、O-2·清除率随质量浓度的增加而增大;溶剂油对·OH、DPPH·的清除率高于同质量浓度的冷榨油;冷榨油对·OH、DPPH·、O-2·的IC50值分别为4.0675、10.3052和0.5415mg/m L;溶剂油对·OH、DPPH·、O-2·的IC50值分别为1.9606、2.9465和1.6053mg/m L。当溶剂油质量浓度达到9mg/m L时,对·OH清除率达到89.79%,其清除效果高于1mg/m L VC对·OH(清除率71.82%)清除效果;当溶剂油质量浓度达到11mg/m L时,对DPPH·清除率达到86.87%,远高于1mg/m L BHT清除率(44.51%)。     

长白山核桃楸种仁抗氧化肽制备及其活性研究

以长白山核桃楸种仁分离蛋白为原料,采用Box-Benhnken响应面法对影响还原能力的主要因素p H、温度、加酶量和底物浓度进行研究。确定其最佳工艺参数为:p H7.6,酶解温度50℃,加酶量4 510 U/g,底物浓度4.6%,时间4 h,该条件下其还原能力为0.35,水解度为16.50%。抗氧化活性试验表明,随着分离蛋白酶解产物浓度的增加,对DPPH、ABTS、·OH的清除作用及还原能力逐渐增加。当酶解产物浓度达到0.8 mg/m L时,对ABTS的清除率为VC的100%,当浓度达到1.2 mg/m L时,对DPPH的清除率达到相同浓度VC的90.08%。浓度继续增加到15 mg/m L时,对·OH的清除作用为VC的94.56%;这说明优化后的核桃楸种仁分离蛋白酶解产物对DPPH和ABTS具有较强的清除作用,对·OH的清除作用比VC弱。     

黄鳍金枪鱼皮胶原肽酶解工艺及抗氧化活性研究

以金枪鱼皮为原料,以肽得率、水解度和感官评价为指标,确定金枪鱼皮胶原肽酶解的最优工艺条件是:中性蛋白酶,酶解时间4 h,酶添加量1 000 U/g,此时肽得率29.03%。体外抗氧化能力测定结果:金枪鱼皮胶原蛋白酶解物具有一定的抗氧化活性,总还原力是VC总还原力的60%;与VC相比,DPPH·清除率(IC50=0.43 mg/m L)、O22-清除率(IC50=3.67 mg/m L)、卵磷脂过氧化物清除率(IC50=14.67 mg/m L)较低,·OH清除率(IC50=0.39 mg/m L)、H2O2清除率(IC50=0.05 g/m L)较高。该酶解物能显著降低油脂的过氧化值,然而降低幅度略低于VC。     

豆渣蛋白肽的酶解工艺、抗氧化作用及其特性研究

以豆渣蛋白为原料、对DPPH·清除率为考察指标,从胰蛋白酶、中性蛋白酶、风味蛋白酶和碱性蛋白酶中筛出中性蛋白酶为最佳水解酶;利用单因素和正交试验探讨豆渣蛋白肽的最佳制备工艺;以抗坏血酸(VC)为对照,研究豆渣蛋白肽的总还原力、对·OH、O·-2的清除作用及对脂质过氧化的抑制作用;研究豆渣蛋白肽的部分特性。结果表明,豆渣蛋白肽的最佳制备工艺为:pH 7,温度70℃,豆渣蛋白浓度4 mg/mL及酶量100 U。VC和豆渣蛋白肽对·OH的半数抑制浓度(IC50)分别为0.274和0.046 mg/mL;对O·-2的IC50分别为0.026和0.084 mg/mL;VC和豆渣蛋白肽的总还原力与其浓度呈剂量依赖关系,且对脂质过氧化有一定抑制能力。豆渣蛋白肽等电点约为3.0,在pH 3~12范围内,其提取率逐渐增加。     

双酶水解玉米醇溶蛋白制备抗氧化肽的工艺优化

为了制备抗氧化活性肽,利用Alcalase碱性蛋白酶和中性蛋白酶分步酶解玉米醇溶蛋白。在单因素的基础上,以1.1-二苯基苦基苯肼(DPPH·)自由基清除率、羟基自由基清除率和水解度(DH)为响应值,采用响应面(RSM)中心组合实验,选取Alcalase碱性蛋白酶加酶量、中性蛋白酶与Alcalase碱性蛋白酶活力之比、底物浓度为自变量,探讨最佳酶解工艺条件。采用Design-Expert软件,通过响应面优化确定修正后各因素的最佳工艺条件为:Alcalase碱性蛋白酶加酶量12880 U/(g底物)、中性蛋白酶与Alcalase碱性蛋白酶活力之比为1∶4,底物浓度为3.4%。在此修正条件下,DPPH·自由基清除率为42.98%,水解度为32.18%,与预测值的相对误差为1.04%。浓度为20 mg/m L时,玉米醇溶蛋白的DPPH·自由基清除率和羟基自由基清除率分别为同浓度VC的85.8%和67.0%。     

碱性蛋白酶酶解魔芋飞粉制备抗氧化多肽

为优化碱性蛋白酶酶解魔芋飞粉蛋白制备抗氧化多肽的条件,采用响应面分析法,以·OH清除率为响应值,研究酶解温度、酶用量、酶解p H值对制备抗氧化肽的影响。此外,还研究了不同分子质量魔芋多肽的抗氧化活性,结果表明:最佳酶解工艺参数:底物质量分数2.25%、温度55℃、酶用量3 228 U/g底物、p H 7.84、水解时间270 min。该条件下抗氧化多肽(18.35 mg/m L)的·OH清除率为73.41%,多肽得率为75.37%。通过Sephadex G-25和Sephadex G-15串联柱分离得到5个多肽组分,其中分子质量为1 500 u和1 000 u的组分抗氧化活性较高,其清除DPPH·的IC50分别为2.82 mg/m L和3.65 mg/m L;清除·OH的IC50分别为9.03mg/m L和14.16 mg/m L;抑制大鼠肝脏自发性脂质过氧化的IC50分别为0.21 mg/m L和0.66 mg/m L;抑制大鼠红细胞H2O2诱导氧化溶血的IC50分别为0.11 mg/m L和0.22 mg/m L。     

中性蛋白酶水解螺旋藻制备抗氧化肽的工艺研究

试验研究了采用中性蛋白酶水解螺旋藻制备抗氧化性肽的最佳工艺。将螺旋藻破壁离心后,用中性蛋白酶水解,以·OH清除率、DPPH·清除率和总还原力为评价指标,在单因素试验基础上,进行了正交试验,确定了最佳酶解工艺条件。试验结果表明,中性蛋白酶水解螺旋藻制备抗氧化肽的最佳工艺条件为:酶解温度为60℃、[E]/[S]为3%、p H为7.3,时间为4 h。此条件下螺旋藻中性蛋白酶的水解物的·OH的清除率是92.790%、DPPH·的清除率为18.941%,代表总还原力大小的吸光度为1.507。     

萝果壳蛋白提取工艺的优化及其抗氧化活性研究

采用碱提酸沉法对萝藦果壳蛋白的提取条件进行研究,以蛋白提取率为指标,在单因素实验的基础上,进行正交实验。结果表明在料液比1∶20(g/m L)、提取液p H11.5、浸提温度60℃、提取时间1.0 h的条件下,蛋白提取率最高,为89.18%。并对最佳条件下提取的蛋白进行体外抗氧化实验。结果显示,提取蛋白对DPPH·、·OH的清除率分别为79.45%(8 mg/m L)、55.35%(8 mg/m L),且清除DPPH·、·OH的半抑制浓度(IC50)分别为4.19、3.30 mg/m L,并具有还原能力,但弱于VC。     

香菇肽提取优化及其体外抗氧化醒酒活性

为探索香菇肽的提取工艺及其体外醒酒活性,深入开发利用香菇的营养功能价值,通过比较香菇不同部位干粉的总抗氧化能力,同时分别采用木瓜蛋白酶、碱性蛋白酶、胰蛋白酶、复合蛋白酶等蛋白酶水解香菇伞粉、足粉、全粉,以水解度和DPPH自由基清除率为指标,选取效果最佳的酶与底物组合,用正交方法分析最佳水解条件。将水解后的多肽进行超滤,选择活性最高肽段,并对此肽段进行体外抗氧化试验,针对其乙醇脱氢酶(ADH)、乙醛脱氢酶(ALDH)的体外激活作用进行研究。结果表明,香菇足柄干粉的总抗氧化能力虽稍次于香菇全粉,但复合蛋白酶水解后的DPPH自由基清除率最高;选用复合蛋白酶水解香菇足柄蛋白的最佳条件为:酶量0.2%,水解温度50℃,水解时间3 h,初始p H 6.0,此酶解条件下氨基含量为29.23%;其中分子质量为5~10ku的肽段具有最高体外抗氧化活性与体外醒酒活性,此肽段清除DPPH自由基能力IC50为0.152 mg/m L,清除·OH能力的IC50为0.190 mg/m L;30 mg/m L香菇肽样品(5~10 ku)对ADH的激活率为(94.58±0.74)%,当其质量浓度为180 mg/m L时对ALDH激活率为(70.69±1.25)%。本研究结果表明香菇肽具有良好的醒酒应用前景。     

油莎豆粕抗氧化肽的制备及其稳定性研究

采用碱性蛋白酶和木瓜蛋白酶对油莎豆粕蛋白质进行复合酶解制备油莎豆粕抗氧化肽,以DPPH自由基清除率为指标,确定制备油莎豆粕抗氧化肽的最佳条件。此外,评价了油莎豆粕抗氧化肽的体外抗氧化活性和稳定性。结果表明,制备油莎豆粕抗氧化肽的最适条件为碱性蛋白酶：木瓜蛋白酶=1∶1,酶的质量分数5%、底物质量浓度46 mg/mL、酶解温度61.7℃、酶解pH 6.7、酶解时间2.5 h,在此条件下,DPPH自由基清除率为88.45%。油莎豆粕抗氧化肽的体外抗氧化活性优良,当油莎豆粕抗氧化肽为5 mg/mL时,DPPH·清除率达88.69%、·OH清除率为42.57%、O■清除率为39.17%、ABTS自由基清除率达87.98%,还原能力为0.2627。油莎豆粕抗氧化肽具有热稳定性及冻融稳定性,在酸性和中性条件下稳定,但不耐受碱性条件,经胃肠消化后,活性下降比较明显。     

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