葡萄皮提取物制备纳米银及其抗菌性能的研究

研究农业废料葡萄皮提取物制备纳米银的方法,分析硝酸银溶液浓度、反应溶液pH对合成纳米银可能存在的影响。采用紫外分光光度计、傅里叶变换红外光谱分析仪、X射线衍射仪、透射电子显微镜对纳米银颗粒进行紫外光谱、可能参与反应官能团、纳米银颗粒形态进行分析。结果表明,葡萄皮提取物中氨基、酰胺基、羧基起关键作用可将硝酸银溶液中的银离子还原为银纳米颗粒。在实验过程中硝酸银溶液在添加葡萄皮提取物后由无色变为棕色,合成的纳米银颗粒紫外特征峰在425 nm处,粒径5 nm左右,对大肠杆菌、金黄色葡萄球菌、假单胞菌具有良好的抗菌性能。     

仙人掌纳米银处理真丝织物的抗菌性能研究

利用纯天然仙人掌液还原制备了纳米银溶液,采用仙人掌纳米银溶液对真丝织物进行了功能性整理,并研究了织物的抗菌性能,讨论了仙人掌纳米银溶液在不同质量浓度、不同温度、不同时间条件下对真丝织物服用件能及抗菌性能的影响,得到了最佳的整理工艺.     

前驱体浓度对生物法制备葡萄籽纳米粒子及其催化性能的影响

葡萄籽提取物通过生物还原制备纳米银粒子,讨论前驱体(硝酸银)浓度对纳米银生物还原制备及其催化性能的影响.结果表明,提高前驱体浓度有利于提高葡萄籽纳米银溶液的产率;葡萄籽纳米银粒子的平均粒径约为40 nm,前驱体浓度变化对葡萄籽纳米银粒子粒径的影响有限.为了测定不同葡萄籽纳米银的催化性能,以硼氢化钠为还原剂,直接紫1和直...     

植物还原银纳米粒子研究进展

为减少环境污染及降低成本,更多研究者开始从事低碳、绿色、环保的纳米银制备工作。现综述了利用植物作为还原剂从银离子溶液中还原银纳米粒子的研究方法,重点阐述植物还原剂的种类及还原机理,并对此类制备纳米银粒子方法的未来进行展望。     

臭常山内生真菌绿色合成纳米银的优化、表征及催化活性研究

为探究臭常山内生真菌Diaporthe orixae sp.nov.用于生物合成纳米银及其催化活性的研究，利用臭常山内生真菌D.orixae菌丝裂解液合成纳米银，对其合成条件进行优化调控，将合成的纳米银进行表征，并进一步考察了合成的纳米银的催化活性。反应时间12 h、菌株生物量5 g、AgNO₃浓度2.0 mmol/L、pH 8、温度55℃为菌株D.orixae菌丝裂解液合成纳米银的最优条件；扫描电镜显示合成的纳米银为球状，分散性较好；X射线衍射图谱显示，合成的纳米银晶体结构为面心立方结构；通过傅里叶变换红外光谱FT-IR分析可得菌株D.orixae自身携带的羟基、羰基、酰胺键等官能团可能有助于纳米银的形成和稳定。此外，该实验合成的纳米银对4-硝基苯酚、甲基橙和亚甲基蓝都有较好的催化活性。臭常山内生真菌D.orixae菌丝裂解液可用于绿色合成纳米银，合成的纳米银在绿色催化降解4-硝基苯酚和有机染料领域具有潜在的研究价值。     

纳米银的抑菌机理及其在食品储藏方面的研究进展

纳米银因具有广谱抗菌、强效杀菌、制备简单、对坏境危害小、不易产生耐药性等优点,被广泛用作各种产品的抗微生物材料。本文重点对纳米银的抑菌性能、抑菌机理,及其在食品储藏保鲜方面的应用进行了综述,旨在为纳米银在食品储藏保鲜方面的进一步开发和利用提供参考。     

微生物合成共轭亚油酸机理的研究进展

相比于共轭亚油酸（CLA）的化学合成,微生物合成CLA与化学法具有培养灵活、对设备要求低、产物分离简单等优势。主要讨论了微生物合成CLA的研究进展,亚油酸（LA）能被微生物转化的原因,以及微生物合成CLA的机理。CLA的合成机理从微生物在动物瘤胃内混合发酵代谢LA和单一微生物在体外合成CLA两方面进行阐述。     

染料的杜仲纳米银粒子催化还原降解

针对合成染料污染环境、不易降解的问题,采用生物还原法制备的杜仲纳米银粒子作为催化剂,NaBH4为还原剂,对合成染料进行催化还原降解,探讨了杜仲纳米银粒子对各种结构染料的催化性能及催化还原降解机理。试验表明:对于双偶氮染料,NaBH4的还原降解能力非常有限,而在同时加入杜仲纳米银和NaBH4的条件下,双偶氮染料可发生有效的催化还原降解,18 min内在最大吸收波长处的吸光度分别下降了84.4%(直接紫1)和60.1%(直接红23);对于杂环类染料,单独使用NaBH4还原剂也可以实现染料特征峰的明显下降,而加入纳米银催化剂后下降的速度显著增加,推断纳米银和NaBH4破坏了杂环染料分子的共轭发色体系。     

采用天草柑果皮提取液制备纳米银

目的用天草柑果皮制备纳米银,并优化其合成工艺条件。方法以纳米银得率为指标,采用单因素和正交试验对反应时间、温度和AgNO_3浓度进行优化。进一步考察上述反应条件对提取液还原率、所得纳米银的平均粒径、粒径分布和zeta电位值的影响。结果各因素对纳米银得率的影响主次顺序为反应温度AgNO_3浓度反应时间。反应最佳条件为反应时间2 h、反应温度90℃、AgNO_3浓度10 mmol/L。在优化条件下,提取液对Ag~+的还原率为91.1%,所得纳米银的平均粒径为29.8 nm,且zeta电位为(-30.8±0.10)mV。结论所得纳米银具有较为均匀的粒径,且在水溶液中可稳定分散,可用做抗菌填料加入食品包装中。     

真丝织物的汽蒸法纳米银抗菌整理

为了实现真丝织物的抗菌性能,以一种含有多胺基化合物(RSD)和硝酸银的混合整理液对真丝织物进行处理,并采用汽蒸法在位还原得到纳米银抗菌真丝织物.对纳米银抗菌真丝织物表面纳米银的形成、纳米银的形态、纳米银的含量、纳米银抗菌真丝织物的白度、抗菌性能和耐久性能等进行了测试与分析.结果表明,当纳米银含量为81.65 mg/kg时,对金黄色葡萄球菌和大肠杆菌的抗菌率分别达99.49%和99.98%,洗涤50次后,对金黄色葡萄球菌和大肠杆菌的抗菌率仍保持在97.43%以上;纳米银抗菌真丝织物的白度影响较小.     

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