快速测定蒽醌含量的可见光谱法

华南理工大学制浆造纸工程国家重点实验室林能镖等人研究了一种快速测定蒽醌含量的可见光谱法。该方法是基于用连二亚硫酸钠(Na2S2O4)在碱性条件下将蒽醌(AQ)还原成蒽氢醌(AHQ),然后在505nm处检测AHQ的吸光度而建立的。结果表明,将AQ转化成AHQ的最佳还原条件为:温度80℃,时间10min,AQ、Na2S2O4和NaOH的摩尔比为1∶3∶50。     

快速测定蒽醌含量的可见光谱方法

华南理工大学制浆造纸工程国家重点实验室林能镖等人研究了一种快速测定蒽醌含量的可见光谱方法。该方法是基于用连二亚硫酸钠(Na2S2O4)在碱性条件下将蒽醌(AQ)还原成蒽氢醌(AHQ),然后在505nm处检测AHQ的吸光度而建立的。结果表明,将AQ转化成AHQ的最佳还原条件为:温度80℃,时间10min,AQ、Na2S2O4和NaOH的摩尔比为1:3:50。该方法的相对标准偏差为2.01%;定量检测极限为2.26mg/L;回收率在95.5%～100%。该方法完全满足商品蒸煮助剂中AQ含量检测的要求。     

粗皮桉AS-AQ法制浆特性的研究

桉木是造纸工业生产的重要原料,具有优良的制浆造纸性能,本研究首次采用粗皮桉为原料,研究其制浆性能,为造纸工业生产提供理论数据。实验的主要结果如下:家系123粗皮桉AS-AQ法蒸煮最佳工艺条件为总碱量(以Na2O计)25%,亚硫酸化度(以Na2O计)0.5,蒽醌0.08%,NP-10用量0.3%,保温时间160min,最高蒸煮温度170℃,液比1∶4.5,家系200的最佳工艺条件为总碱量(以Na2O计)23%,亚硫酸化度(以Na2O计)0.50,蒽醌0.08%,NP-10用量0.3%,保温时间150min,最高蒸煮温度170℃,液比1∶4.5。     

加拿大一枝黄花制浆研究(系列报道之三)碱-蒽醌法蒸煮性能的研究

对加拿大一枝黄花碱-蒽醌法蒸煮性能进行了研究。结果表明：适宜的AP（烧碱）＋AQ（蒽醌）法蒸煮工艺条件是：用碱量17％（以Na2O计），AQ用量0．1％，蒸煮最高温度160℃，保温90min。液比1：4。此蒸煮条件下浆料的得率47．16％，卡伯值25．1，残碱15．98g／L（以Na2O计）。适宜的KP（硫酸盐）＋AQ法蒸煮工艺是：用碱量17％（以Na2O计），硫化度20％，AQ用0．1％，液比1：4，蒸煮最高温度160℃，保温时间90min。此工艺条件下浆料的得率48．44％，卡伯值21．8，残碱8．74g／L（以Na2O计）。AP＋AQ法和KP＋AQ法能显著降低浆料硬度，是生产可漂浆适合的蒸煮工艺。在相似的蒸煮条件下，AP＋AQ法和KP＋AQ（硫化度20％）法浆料性能差异不大。     

麦草浆留硅制浆工艺

在烧碱-蒽醌法制浆工艺中加入氧化铝可以提高硅在未漂麦草浆中的留着,提高纸浆纤维的灰分及二氧化硅含量,解决或减轻黑液“硅干扰”问题。本课题主要研究最佳留着浆料中的灰分及二氧化硅的蒸煮工艺。实验结果证明:将NaOH、AQ以及Al2O3混合均匀后再与麦草原料混合,在用碱量为14%,Al2O3用量为3%,蒽醌用量为0.05%,液比1∶5的条件下,升温60min内到达155℃后保温30min卸锅,该工艺可以达到最好的留硅效果。     

光叶楮白皮碱性过氧化氢草酸盐法制浆工艺条件的优化

讨论了影响光叶楮白皮制浆的各种因素,筛选出APO(碱性过氧化氢草酸盐)法制浆的最佳工艺条件为:H2O2用量9%,Na2C2O4用量20%,NaOH用量9%,AQ用量0.10%,EDTA用量0.20%,液比1∶9,最高温度85℃,保温时间3 h。在此条件下制浆,所得浆料得率63.5%,高锰酸钾值7.6,白度69.7%ISO。     

盐对可食性大豆分离蛋白膜亲水性影响的研究

在大豆分离蛋白(SPI)膜中添加NaCl、Na2CO3、Na2S2O3、Na3PO4、Na4P2O7、ZnCl2和FeCl3,通过研究膜的水分含量(WC)、可溶性干物质(TSM)、水蒸气透过系数(WVP)及其动态接触角(DCA)系统考察盐对SPI膜亲水性的影响。结果表明:NaCl和FeCl3使得SPI膜的WC分别增加7.4%和15.5%,Na4P2O7、Na2S2O3、Na3PO4、Na2CO3和ZnCl2分别使WC减少18.8%、18.9%、3.8%、7.6%和16.1%;NaCl和Na2S2O3使SPI膜的TSM略有增加,但Na3PO4、Na2CO3、Na4P2O7、ZnCl2和FeCl3使TSM分别降低32.3%、13.7%、7.1%、12.7%和23.9%;Na3PO4、Na4P2O7、Na2CO3和Na2S2O3及ZnCl2分别使WVP增加88.9%、51.4%、36.5%、28.7%和21.0%,NaCl不改变膜的WVP,而FeCl3使膜的WVP值略有下降;NaCl、Na2CO3、Na2S2O3和FeCl3使SPI膜在极性和非极性溶剂中的DCA均降低,而Na3PO4、Na4P2O7和ZnCl2使得SPI膜在极性和非极性溶剂中的DCA均提高。     

蒽醌在硫酸盐制浆中的溶解特性及对蒸煮的影响

研究了蒽醌(AQ)在含木素的碱性溶液中表观"溶解"性--即AQ被分散成细微颗粒,并根据其质量传递机制研究了在硫酸盐蒽醌法蒸煮中蒽醌的作用效果.研究发现,AQ可明显"溶于"含木素的碱性溶液,当溶液中木素的含量达到40g/L,在温度90℃时,AQ的溶解度达到0.14g/L,但是溶解速度较慢.在碱性溶液中,蒽醌细微颗粒可被木片吸附,吸附在木片表面上的蒽醌细微颗粒可进一步被木片中的还原基团还原,形成高表面浓度的、完全溶解的蒽氢醌(AHQ),并渗入木片内部,从而加速蒸煮过程木素的溶出.     

蒽醌在不同制浆方法中的应用

蒽醌(Anthraquione,简写AQ)及其衍生物作为添加剂用于制浆,已广为世界各国所采用,其效能亦为大批制浆生产实践所证实。然而,在不同制浆方法中蒽醌作用的差异,仍有待于我们进一步认识。本文试就烧碱蒽醌法(NaOH—AQ)、硫酸盐蒽醌法(KP—AQ)、碱性亚硫酸盐蒽醌法(AS—AQ)、中性亚硫酸盐蒽醌法(NS—AQ)四种制浆方法分述如下: 一、NaOH—AQ制浆实验表明,NaOH法蒸煮与KP法蒸煮相比如果要求浆中木素含量同为2.23％。NaOH法蒸煮须比KP法蒸煮再延长3小时,此时粗浆收获率将比KP法低     

花竹碱法蒸煮中添加蒽醌的效果

蒽醌(AQ)法制浆是七十年代发展起来的一项新技术。AQ和它的衍生物对加快蒸煮速率的研究认为,在碱法蒸煮中,AQ作为一种氧化—还原催化剂,首先使纤维素、半纤维素上的还原性末端基氧化成糖醛酸末端基,从而抑制它们的碱性剥皮反应,提高纸浆得率,AQ本身还原成蒽氢醌(AHQ).还原了的蒽氢醌又使降解了的木素继续还原降解,从而加     

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