二氧化硫脲漂白废纸脱墨浆的工艺优化

用二氧化硫脲(FAS)漂白混合废纸脱墨浆,探讨FAS用量、NaOH与FAS的碱比、浆浓、漂白温度和漂白时间对漂后纸浆白度的影响。结果表明,浆浓8%,FAS用量0.6%,温度80℃,时间60min时,NaOH与FAS的碱比0.5∶1最佳,浆的白度可达82.8%ISO,白度增值为5.4%ISO;延长漂白时间到65min,碱比调整为0.4:1或0.45:1,浆白度可达82.4%ISO,白度增值为5.0%ISO。     

马尾松硫酸盐浆高压高温H2O2漂白

研究了马尾松低卡伯值硫酸盐浆高压高温H2O2漂白,探讨了漂白过程中压力、温度、时间、H2O2用量、Na2SiO3用量以及NaOH用量对漂后纸浆白度的影响.实验结果表明,在压力1.2MPa左右,温度125～130℃,时间1h左右,H2O2用量为4%～5%,Na2SiO3用量为3%,NaOH用量为1%,浆浓为10%的条件下,漂后纸浆白度可达80%ISO以上.     

四羟甲基磷酸膦用于马尾松热磨机械浆漂白

采用四羟甲基磷酸膦(THPS)漂白马尾松热磨机械浆,探讨THPS用量、初始pH值、漂白时间和漂白温度对漂后纸浆白度的影响。研究结果表明,THPS漂白马尾松热磨机械浆的适宜条件是:浆浓10%,THPS用量2.0%,初始pH5.0,漂白时间2h,温度90℃时,漂后纸浆白度达到63.07%ISO,白度增值为7.07%ISO。通过比较连二亚硫酸盐(Y)漂白和THPS漂白的效果,当THPS用量为0.1%,Y用量为1.0%时,漂后纸浆的白度达到61.12%SO,比未漂浆的白度提高了5.12%ISO。     

马尾松低卡伯值硫酸盐浆高效H2O2漂白

研究了马尾松低卡伯值硫酸盐浆高压高温H2O2漂白,探讨了漂白过程中压力、温度、时间、H2O2用量、Na2SiO3用量以及NaOH用量对漂后纸浆白度的影响.实验结果表明,H2O2漂白在压力1.2MPa左右,温度125～130℃,时间1h左右,H2O2用量为4%～5%,Na2SiO3用量为3%,NaOH用量为1%,浆浓为10%的条件下,漂后纸浆白度可达80%ISO以上.     

光催化漂白硫酸盐浆的研究

利用自制光催化漂白反应器,以TiO2为光催化剂,在紫外光照射下,对针叶材硫酸盐木浆光催化漂白过程的主要影响因素进行了探索.以纸浆白度为评价指标,系统考察了紫外光催化降解时间、光照模式、初始PH值、浆浓等指标的影响.结果表明:随着光催化漂白时间的增加,漂后浆的白度上升;当光催化剂用量为1.0g/L、初始pH=4.0、浆浓为0.5%、紫外光照射条件下,光催化漂白6h后漂后浆白度此未漂浆白度可提高11.06%ISO.SEM与FIIR分析表明:TiO2光催化漂白主要是以保留木素为主,浆料经光催化漂白后浆中残余木素与未漂浆残余木素的结构变化不大,纤维结构在漂白过程中未受影响.     

马尾松CTMP的H_2O_2漂白影响因素分析

化学预热机械浆(CTMP)在我国得到了迅速发展,H2O2漂白是化学机械浆漂白的主要方法之一,本论文主要研究了在马尾松CTM的H2O2漂白中各个工艺条件,即H2O2、NaOH、Na2SiO3和MgSO4的用量及温度、浆浓和反应时间,对漂后纸浆白度和返黄值(PC值)的影响.实验结果表明,H2O2和NaOH用量是影响纸浆白度和PC值的主要因素;Na2SiO3可以提高纸浆的白度和降低纸浆PC值;MgSO4会降低纸浆白度,但对纸浆PC值的影响较小;而浆浓、温度及反应时间对纸浆白度和PC值的影响较小.马尾松CTMP的最佳工艺条件为H2O2 4%,NaOH 3%,Na2SiO3 2%,浆浓12%,温度70℃,时间2h.在此条件下,纸浆白度达到67.0%ISO,PC值为2.23.     

四乙酰乙二胺(TAED)对稻草高得率浆双氧水漂白的影响

研究了四乙酰乙二胺(TAED)作为活化剂对稻草高得率浆双氧水漂白的活化效果,并在TAED的作用下以漂后白度为指标考察不同条件对活化效果的影响,以此确定最佳漂白条件。结果表明:最佳漂白工艺为浆浓10%,时间30min,温度70℃,TAED与H2O2摩尔比0.5,NaOH用量4%,H2O2用量6%,Na2SiO3用量3%,MgSO4用量0.05%;在该条件下,漂后浆的白度值为52.4%ISO,比原浆白度增加值可达38.6%ISO,比单纯的H2O2漂白提高了7.8%ISO。     

杨木化学浆甲脒亚磺酸-过氧化氢的漂白工艺

甲脒亚磺酸(FAS)是一种新型漂剂,在工业上也称二氧化硫脲。以杨木为原料,研究在CEHP漂白流程中的过氧化氢(P)漂段添加漂白助剂甲脒亚磺酸后的最佳漂白工艺及结果。结果表明,当FAS用量0.4%、H2O2用量1.8%、温度70℃、时间100min、NaOH用量1.7%时,纸浆漂白后得率97.61%,白度85.12%ISO,抗张指数17.65N.m.g-1。相比于CEH三段漂后78.45%ISO以及未添加FAS时CEHP漂后82.22%ISO的纸浆白度,白度增值分别为6.67%ISO、2.90%ISO。FAS-H2O2漂白工艺节省了漂白时间,节约了漂剂,同时提高了纸浆白度。     

烧碱-蒽醌法麦草浆OHP漂白

对Soda-AQ麦草浆少污染OHP漂白进行了研究.实验结果表明,使用少污染OHP三段漂白,氧漂时NaOH用量3%,未漂浆的脱木素率达44.03%,随后的次氯酸盐漂白只需3%有效氯用量即可将浆料漂至75.05%ISO,再用2%H2O2进行漂白,纸浆最终白度可达80.55%ISO,纸浆黏度为464.9mL/g.     

二氰二胺用于马尾松硫酸盐浆的漂白

通过正交试验研究二氰二胺在马尾松硫酸盐浆漂白中的应用。结果表明:在过氧化氢漂白段影响纸浆白度的主要因素是二氰二胺用量,其次是漂白时间和氢氧化钠用量,而温度对漂白的效果影响最小。过氧化氢漂白段的适宜工艺条件为:过氧化氢用量3%,浆浓10%,二氰二胺用量1.6%,漂白时间60min,氢氧化钠用量3%,漂白温度70℃,硫酸镁用量0.5%,硅酸钠用量3%。在上述适宜条件下,漂后纸浆白度可达90.57%ISO,较未添加二氰二胺的漂后纸浆白度提高5.57%ISO。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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