麦草生物化机浆过氧乙酸与过氧化氢漂白

研究了麦草生物化机浆CH3COOOH漂白条件以及CH3COOOH与H2O2的组合漂白.结果表明:麦草生物化机浆过氧乙酸适宜漂白条件为:3%CH3COOOH、90min、50℃、pH5.经PaP3P3a和PaP5P5a漂白,麦草生物化机浆的白度分别可达61.9%和72.1%(IS0).     

氧碱蒸煮麦草浆的活化H2O2漂白

研究了活化H2O2漂白过程中药品用量、漂白时间、温度、漂液pH值以及2种活化剂——TAED(四乙酰乙二胺)和乙酸酐协同作用等因素对浆料白度的影响，结果表明，采用三段漂P1P2A，当P1段H2O2用量6％、TAED用量3％、乙酸酐用量5％，TAED在pH值为9．5左右加入(本实验中时间约为50min左右)；P2段H2O2用量4％、TAED用量2％、乙酸酐用量4％；A段H2SO3用量2％时，可获得较高的浆料白度(75．2％ISO)。漂白浆所测强度指标均与普通烧碱-AQ浆的CEH漂白浆相似。     

麦草生物化机浆可漂性研究

研究了麦草生物化机浆的H2O2漂白条件;ClO2、CH3COOOH以及木聚糖酶对麦草生物化机浆H2O2漂白的影响。结果表明:ClO2活化、CH3COOOH漂白以及木聚糖酶预处理对麦草生物化机浆H2O2漂白都起到较好效果。麦草生物化机浆较佳的碱性H2O2漂白条件为:5%H2O2、2%NaOH、180min、85℃;经DP5P5a、P5PaP5a和XP5aP5a多段漂白,麦草生物化机浆的白度分别可达71.2%、72.1%和74.6%(ISO)。     

影响ClO2终段漂效率的因素

研究了D0EpD1D2漂白流程中终段漂（D2）的漂白效率,重点研究了浆料漂白过程中pH值的影响。样品浆为卡伯值为14．8的未漂硫酸盐蓝桉浆和氧脱木素至卡伯值为9．8～12．0的未漂硫酸盐蓝桉浆。采用D0EpD1漂序将样品浆漂至白度均为86％,然后在相同条件（如ClO2用量、反应时间和温度、终点pH值）下进行D2段漂,终漂浆的目标白度是90．5％。漂白过程中,监测浆料卡伯值、白度、黏度的变化及己烯糖醛酸、4-O-甲基葡萄糖醛酸和羧基的含量。当D2段的终点pH值由3．0提高至6．5时,终漂浆白度提高。当终点pH值为4．5～6．5时,D2段漂后的所有浆料都可达到90．5％的目标白度,但需控制终点DH值。浆料黏度在pH值为3～5时最佳。尽管D0EpD1工段的漂白条件不同,但经D1段漂后,样品浆具有相近的木素残余量（通过分析卡伯值得到）,但己烯糖醛酸含量变化较大（2～26mmol／kg）。电导滴定法表明,D1段漂后,各样品浆的羧基含量不同,其中己烯糖醛酸只占一小部分。D2段漂前的漂白条件不同导致纤维电荷量不同。纤维电荷量会影响D2段漂的碱需求量,而碱需求量的不同又影响初始pH值和相关的过程动力学。漂白终点pH值较高时,较低的纤维电荷量有助于提高终漂浆的白度和黏度。     

酸性亚硫酸盐法杨木浆全无氯漂白实验

用4种全无氯漂白程序对酸性亚硫酸盐法杨木浆分别进行漂白实验.结果表明,经酸性DTPA预处理后,用H2O2强化氧漂或者用尿素预浸的H2O2强化氧漂,漂浆白度分别为84.3%和85.1%ISO,浆料粘度分别为962和931 mL/g.对上述两种漂白浆再进行常规DTPA处理,然后分别进行H2O2强化氧漂和碱性H2O2漂白,漂浆白度分别为95.2和91.0%ISO,浆料粘度为904和955mL/g.     

FAS在杉木CTMP漂白中的应用研究

对杉木CTMP组合漂白中的FAS漂白进行了研究.结果表明,FAS漂白中m(NaOH):m(FAS)的最佳值为0.5,FAS适宜进行高温短时间漂白,90℃、30 min时漂白效果良好.FAS与H2O2结合的两段漂白可以将浆料漂白至更高的白度,其中FAS漂白置于H2O2漂白之后,可获得更好的漂白效果,与FAS漂白置于H2O2漂白之前相比,白度可提高1～2个百分点.以FAS漂白为结束段的三段漂白,浆料色相得到改善,白度达到82.8%,且其废水污染负荷和色度较低.FAS漂白对漂白浆料强度性能无不良影响,与未漂浆相比,含FAS的三段组合漂白浆的抗张指数(28.2 N·m/g)、撕裂指数(4.70 mN·m2/g)和耐破指数(1.62 kPa·m2/g)分别提高了100%、22%和70%.     

慈竹化机浆漂白性能研究

对慈竹单段漂白和多段组合漂白性能进行了系统研究,提出了慈竹化机浆漂白至71%以上白度的工艺。研究结果表明,H2O2总用量10%,慈竹化机浆经单段H2O2漂白,白度只能达到64.7%~65.0%;两段H2O2漂白具有较高的漂白效率,漂白浆白度达到66.6%~67.1%;总漂剂用量为12%的三段组合漂白,结束段分别使用H2O2、FAS和Na2S2O4不同漂白方式,FAS漂白效率最优,白度达到72.9%;其次是H2O2漂白,白度为71.9%;以FAS为结束段的漂白,与本色慈竹化机浆相比,抗张指数、耐破指数和撕裂指数分别提高200%~300%、250%~300%和250%~270%。采用碱性Na2SO3化学预浸渍,两段H2O2漂白加一段FAS漂白的三段组合漂白,慈竹化机浆可漂白至71%以上的白度。     

硬杂木硫酸盐浆的少氯漂白

对硬杂木硫酸盐浆的少氯漂白进行了研究。HHP三段漂与HP两段漂对比研究结果表明,HP两段漂浆料的黏度随H段有效氯用量的增大而降低,H段漂后浆料白度越高,经P段漂后浆料白度增值越低;在次氯酸盐段总有效氯用量相同时,HHP漂后浆料的白度均高于HP漂;HHP三段漂白的第1段有效氯用量3%、第2段有效氯用量2%、H2O2用量3%时,硬杂木KP可漂到78%~80%的白度。红外光谱分析结果表明,H2O2漂白主要使浆料中的共轭羰基减少或苯环结构的破坏与溶出。     

尾叶桉低卡伯值KP浆的高效H2O2漂白

研究了高压高温条件下尾叶桉低卡伯值KP浆的H2O2漂白,讨论了压力、温度、时间、化学药品用量等条件对漂白结果的影响.结果表明,在1.2MPa、120℃条件下漂白40min,H2O2用量2%时氧脱木素浆的漂后白度达88.2%ISO;H2O2用量6%时未经氧脱木素浆的漂后白度达88.6%ISO;高压高温漂白浆料白度提高的快速阶段在升温阶段,即反应开始的前30min内,浆料白度增值已达最大白度增值的96%以上.     

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.     

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