石榴皮多酚提取物对亚硝酸盐的体外清除作用研究

以清除率为指标,研究了石榴皮多酚提取物的浓度、反应温度、反应时间和pH对该提取物体外消除亚硝酸盐作用的影响.结果显示,石榴皮多酚提取物对亚硝酸盐具有较强的清除作用.在浓度为4.0 mg/mL时,其对亚硝酸盐的清除率达到83.17%,并且该清除作用随多酚提取物的浓度和反应时间的增加而增大,随反应介质pH的增大而减少,随反应温度的增加呈现先增加后降低的趋势.石榴皮多酚是一种有效的亚硝酸盐清除剂,可用于发酵蔬菜和添加亚硝酸盐作为发色剂肉制品的加工.     

桑叶黄酮对亚硝酸盐的体外清除作用研究

研究了桑叶黄酮在不同反应pH、温度、时间及浓度下对亚硝酸盐的清除作用及其体外抗氧化作用。结果显示:桑叶黄酮具有较强的清除亚硝酸盐能力,在浓度为0.2mg/mL时,其对亚硝酸盐的清除率最大可达到75.69%,该清除作用随着反应时间、温度及浓度的增加而增大,随pH增大而减小。桑叶黄酮对亚硝酸盐的清除作用与其抗氧化活性有一定相关性。     

响应面法分析优化大蒜对腌肉中亚硝酸盐清除工艺的研究

实验采用盐酸萘乙二胺分光光度法测定了大蒜对亚硝酸盐的清除率,并用Box-Benhnken中心组合设计和响应面分析对大蒜清除率的主要影响因素即浸提温度、浸提液用量、反应液pH值、反应时间、浸提时间进行多项式回归模型建立和最优化.结果表明大蒜清除率的最佳工艺条件为:浸提温度78℃、浸提时间14 min、反应液pH值4.2;浸提液用量3.81 mL、反应时间21 min.将研究结果用于腌肉中亚硝酸盐的清除,作用效果显著.     

荔枝皮色素体外清除亚硝酸盐作用研究

采用分光光度法,测定荔枝皮色素体外清除亚硝酸盐能力,并与茶叶提取液和VC 对亚硝酸盐的体外清除作用进行比较。结果表明,荔枝皮色素同亚硝酸盐反应10min,对亚硝酸盐的清除基本完全,亚硝酸盐的清除率随荔枝皮色素添加量的增加先增大而后趋于稳定。加热处理、反应体系酸性pH 值能有效增强荔枝皮色素对亚硝酸盐的清除效果。100℃加热10min 条件下,1mg/mL 和10mg/mL 的VC 对亚硝酸盐清除率均最高,荔枝皮色素在低质量浓度(1mg/mL)时对亚硝酸盐清除率为(42.76±0.98)%,高于同质量浓度的茶叶提取液对亚硝酸盐的清除率((37.92±0.79)%)(P ＜ 0.05),但在高质量浓度(10mg/mL)下对亚硝酸盐的清除率则低同质量浓度的茶叶提取液(P ＜ 0.05)。体外模拟胃酸和体温条件下,荔枝皮色素保持较高的亚硝酸盐清除效果,1mg/mL 和10mg/mL 时的清除率分别为(23.55 ± 0.45)% 和(51.62 ± 0.91)%。     

反应条件对沙棘果提取物降解亚硝酸盐效果的影响

以沙棘果为原料,采用溶剂提取法制取沙棘果提取物,研究添加量、反应温度、反应时间和反应pH值对沙棘果提取物降解亚硝酸盐效果的影响,优化了沙棘果提取物降解亚硝酸盐的反应条件。结果表明:影响沙棘果提取物亚硝酸盐降解率的主要因素是反应p H值,其次是反应温度和添加量,反应温度和pH值之间的交互作用对亚硝酸盐降解率影响显著。在提取物添加量6 mL,反应温度50℃,反应时间20 min,pH 2的反应条件下,沙棘果提取物亚硝酸盐降解率达到96.10%。     

绿原酸、异绿原酸A抑制亚硝化反应研究

研究绿原酸、异绿原酸A抑制亚硝化反应的能力及最适作用条件。结果表明,绿原酸类物质清除亚硝酸盐及阻断亚硝胺合成的效果随浓度、反应时间和温度的升高逐渐增强,随pH值的升高而降低。清除亚硝酸盐的最适质量浓度5μg/μL,pH3.4,反应时间40 min,反应温度47℃;阻断亚硝胺合成的最适质量浓度3μg/μL,pH2.8,反应时间20 min和反应温度47℃;抑制亚硝化反应最适条件为样液质量浓度5μg/μL,pH 2.8,反应时间40 min,温度47℃。在抑制亚硝化反应方面,绿原酸与VC效果相当,均弱于异绿原酸A,三者均弱于芦丁。绿原酸和异绿原酸A都有较好的抑制亚硝化反应的能力,且随反应体系环境的变化而存在差异。     

香辛蔬菜苦藠粗提液对亚硝酸盐的清除作用

研究苦藠在不同实验条件下对亚硝酸盐的清除能力。选择苦藠粗提液不同的预热温度、pH 值、用量及反应时间进行单因素试验,并在此基础上进行正交试验,以探明清除效果随反应条件所发生的变化。结果表明：高温预热很必要,在苦藠自然pH 值下清除率可达50% 以上;pH 值对清除率影响极显著,pH2.0、11.0mL 的粗提液,反应10min,清除率达到82.7%。以芥菜为对象,设置①预煮后浸于苦藠粗提液中(模拟烹饪),7℃冷藏,以去离子水浸泡为对照,观察芥菜中亚硝酸盐的积累;②鲜叶去污染后PE 包装置于40℃条件下(模拟高温贮运环境),检测叶片亚硝酸盐的变化。贮存达13d 时,两种浸泡液中芥菜亚硝酸盐的积累都较缓慢,苦藠液中芥菜亚硝酸盐含量始终低于对照,提示煮沸、低温、添加苦藠均有抑制亚硝酸盐形成的能力;40℃条件下,前4d 中,亚硝酸盐含量虽略增但均很低,其后亚硝酸盐含量跃增,第6 天时达到356.4mg/kg,2.0mL 苦藠粗提液在第1、6天的清除率分别为21.1% 和5.9%。     

苦瓜多糖对胰脂肪酶抑制作用的研究

研究测定苦瓜多糖在不同的反应条件下对胰脂肪酶的抑制率,探讨了浓度、pH、反应时间、反应温度等条件下苦瓜多糖对胰脂肪酶活性的影响。结果表明,苦瓜多糖浓度为30mg/mL,pH为7.5,反应时间为15min,反应温度为37℃时,对胰脂肪酶的抑制效果最佳。在此条件下,苦瓜多糖对胰脂肪酶半抑制浓度IC50为29.86mg/mL,抑制率为51.24%。抑制类型为非竞争性抑制作用,抑制常数Ki=21.62mg/mL。苦瓜多糖对脂肪酶具有明显的抑制作用,为新型减肥药物的开发提供了新的思路。     

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%。     

谷氨酰胺转氨酶改性菜籽蛋白凝胶特性的研究

为改善菜籽蛋白质的凝胶特性,采用谷氨酰胺转氨酶(TG)以单因素试验和正交试验研究影响菜籽分离蛋白(RPI)凝胶特性的主要因素-- TG 质量浓度、pH 值、反应温度和反应时间。结果表明：反应温度和 pH 值对菜籽分离蛋白凝胶性的影响显著,同时得到谷氨酰胺转氨酶改性菜籽蛋白凝胶特性的最佳工艺条件,RPI 质量浓度1.5g/10mL、加酶量50U/g RPI、pH9.0、反应温度40℃、反应时间20min。     

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