大麻纤维高温闪爆联合脱胶技术

研究大麻纤维高温闪爆联合脱胶工艺,讨论高温闪爆联合处理条件对大麻纤维性能及组分分离效果的影响。用FTIR、SEM对联合脱胶后大麻的表面形态结构和化学成分进行分析。研究发现:半纤维素和木质素的含量分别下降了81152 %和86168 % ,纤维素比率明显提高,达到大麻纤维脱胶的目的;工艺中高温蒸煮温度、用碱量、闪爆前处理、闪爆压力及温度,保压时间及闪爆次数等是影响纤维分离的重要因素;高温蒸煮及预浸处理对纤维的溶胀作用有利于闪爆条件的降低     

等离子体酸对大麻脱胶效果的初步研究

为优化大麻脱胶工艺,降低碱用量,减少环境污染,研究了等离子体酸-碱联合脱胶工艺。通过对等离子体酸预处理条件进行单因子实验,得出较好的脱胶工艺条件为浴比1∶20,温度60℃,时间1 h。在此条件下采用低碱浓度工艺进行二次处理,即碱浓度8%,浴比1∶10,温度90℃,时间1 h。处理后大麻纤维素含量为78.63%,果胶、半纤维素、木质素分别降低了87.3%,40.7%和64.5%,果胶的去除效果较好,纤维手感柔软,提高了大麻纤维的可纺性能。     

蒸煮温度与碱用量对大麻纤维晶体结构与热性能的影响

研究了大麻纤维高温脱胶技术,讨论了不同蒸煮温度和碱量处理对大麻纤维晶体结构及热稳定性能的影响.用XRD和TG技术对高温脱胶后的大麻纤维晶体结构和热稳定性能进行了表征.试验结果表明:高温蒸煮处理提高了大麻纤维的结晶度、结晶指数和热稳定性,其结晶度、结晶指数和热稳定性与NaOH的用量及反应温度有关;大麻纤维的热稳定性与纤维的晶体结构有关;其最大速率分解温度的升高可能是受纤维素晶体中更高次序的纤维素结构、晶粒尺寸变大和分子链堆砌紧密程度提高所致.     

桑皮纤维的脱胶工艺研究

参考大麻纤维的脱胶工艺,研究了酸温度、酸浓度、碱浓度、煮练时间等对桑皮纤维脱胶效果的影响。结果表明:酸处理温度60℃、酸浓度2.5 g/L、碱浓度1.5 g/L、煮练时间为2 h时,脱胶的效果最佳。     

黄麻纤维高温脱胶工艺初探

借鉴硫酸盐蒸煮法,对黄麻纤维的精细化工艺进行了初步探讨.研究了高温碱煮练结合预氧处理工艺对黄麻纤维脱胶的方法,并运用正交分析方法,着重分析了煮练温度、NaOH浓度和硫化度3个因子对黄麻纤维脱胶效果的影响.通过比较黄麻纤维脱胶后的细度、断裂强度等指标,得出了高温碱煮练精细化工艺处理黄麻纤维的优化工艺参数.结果表明采用硫酸盐蒸煮原理对黄麻纤维进行高温碱煮练是一种有效的脱胶途径.     

高温脱胶对大麻纤维成分与结构的影响

研究了大麻纤维高温脱胶技术,讨论了脱胶温度和碱量对大麻纤维成分与结构的影响。用SEM、FT-IR、XRD对大麻纤维高温脱胶前后的表面形态结构、聚集态结构进行了表征。实验结果表明:高温脱胶后大麻纤维中的半纤维素和木质素含量分别下降了79.1%和83.5%,纤维素含量提高;大麻纤维的结晶度上升,其结晶度与NaOH的质量分数及反应温度有关。     

大麻纤维超临界CO2脱胶工艺

为解决大麻纤维脱胶效果差和水资源短缺等问题,采用超临界CO2代替水对大麻纤维进行脱胶,并探讨了脱胶温度、脱胶压力、脱胶时间和CO2流量对大麻纤维残胶率和果胶含量的影响.采用扫描电镜(SEM)对脱胶前后纤维的表面形貌进行分析.大麻纤维较优的脱胶工艺条件为:脱胶温度100℃、脱胶压力24 MPa、脱胶时间90 min、CO...     

棉秆皮的生物脱胶工艺因素分析

针对传统化学蒸煮为主的棉秆皮脱胶方法提取棉秆皮纤维时易产生碱废水污染环境的缺点,采用生物脱胶工艺提取棉秆皮纤维。运用正交试验对棉秆皮的果胶酶脱胶工艺进行了优化,分析了果胶酶制剂的浓度、处理时间、温度、处理的pH值四个因素对生物脱胶的影响。对正交实验的结果进行分析后得出棉秆皮纤维脱胶优化工艺条件是酶制剂浓度12%(owf),温度40℃,时间30h,pH值4.4,浴比1∶30。在优化工艺条件下对棉秆皮纤维的性能进行了测试,结果表明其性能优良。     

荨麻高温高压化学脱胶工艺

为了探究荨麻纤维高温高压脱胶技术,设计了高温高压化学脱胶碱煮工艺的NaOH用量、温度和时间3个影响因素的单因素试验。通过残胶率以及单纤维强力的测试来评价脱胶后得到的精干麻的脱胶效果。最终通过正交试验,得出最佳脱胶工艺。结果表明,高温化学脱胶方法可以用于荨麻的脱胶。最佳的碱煮方案是:NaOH浓度5 g/L,碱煮时间55 min,碱煮温度135℃。     

脱胶工艺对棉型化大麻纤维主体长度的影响

大麻纤维长度是影响其纺纱性能的重要指标之一,直接关系到与棉纤维混纺时的加工性能和使用价值,应用合理的脱胶方法与工艺可以得到理想的棉型化大麻纤维长度.因此,文章使用化学法对大麻纤维进行脱胶,针对主要工艺参数脱胶温度、煮练时间以及碱液质量浓度对纤维主体长度的影响进行重点讨论.采用手排分组称量法,将脱胶后的纤维由长至短进行整理、分组、称量,求出纤维长度特征数(主体长度)、短绒率.通过理想主体长度与较低短绒率得出最佳脱胶工艺参数为:煮练时间150min,脱胶温度110℃,碱液质量浓度7g/L.     

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