荻自催化乙醇法制浆反应历程的研究

对获采用自催化乙醇法制装的反应历程进行了研究,研究结果表明：(1)木素的脱除分两十阶段：大量脱除阶段和残余脱除阶段;(2)木素脱除与碳水化台物的脱除和黑液的pH值关系很大;(3)成浆中保留了原料中的大部分灰分,而有机溶剂抽出物的古量则很低;(4)蒸煮至纤维分离点时浆中仍古有较高量的木素,应继续保温。     

麦草自催化乙醇制浆工艺及反应历程的研究

通过正交实验确定了麦草自催化乙醇制浆的工艺条件,并对其反应历程进行了研究。正交实验结果表明最佳工艺条件为：蒸煮温度195℃、液比1∶8、保温70min(升温120-130min)、乙醇和水的比例为55∶45。蒸煮脱木素历程分析表明麦草乙醇蒸煮可分为两个阶段：大量脱木素阶段和残余木素脱除阶段。     

皇竹草KP-AQ法蒸煮性能及反应机理的研究

利用正交实验法提出皇竹草KP-AQ适宜蒸煮条件，并在该条件下研究了其蒸煮反应历程，对蒸煮纤维分离点作了探索。研究结果表明，皇竹草KP-AQ较佳蒸煮工艺条件为：用碱量17％(Na2O计)，硫化度15％，液比1：4，AQ用量0．08％，最高温度160℃，保温30min，细浆得率51．26％，卡伯值10．7；KP-AQ蒸煮脱木素具有阶段性，大量脱木素阶段为升温至105℃，脱除木素约68．03％(对原料中总木素)，补充脱木素阶段为105℃至160℃，保温约10min，脱除木素27．35％，残余脱木素阶段为在160℃下保温10—70min，脱除木素为1．48％；蒸煮纤维分离点在总蒸煮时间120min、蒸煮温度约160℃左右，粗浆得率53．2％，细浆卡伯值15.8，浆中总木素2．80％，总木素脱除率93．5％；碳水化合物、灰分和碱耗等变化具有禾草类相似的规律。     

过氧化氢在芦苇乙醇法制浆中的催化作用

对比研究了芦苇自催化乙醇法与H2O2催化乙醇法制浆的木素脱除规律.研究结果表明:在芦苇乙醇法制浆过程中添加H2O2,蒸煮体系pH值低于自催化乙醇法;提高了木素脱除速率,而细浆得率下降较少,纤维分离点所对应的保温时间没有提前;脱木素的反应级数和阶段没有改变,但提高了反应速率常数.     

棉秆硫酸盐法和烧碱-蒽醌法蒸煮历程的研究

研究了棉秆全秆硫酸盐法蒸煮和烧碱-蒽醌法蒸煮历程,分析了木素含量、木素脱除率、纸浆得率和碳水化合物降解率的变化.结果表明,棉秆硫酸盐法蒸煮与烧碱-蒽醌法蒸煮具有相似的蒸煮历程,脱木素过程分3个阶段:第1阶段,升温到140℃,属于脱木素初期阶段,木素脱除率达到45%左右;第2阶段,温度由140℃升到160℃,保温30min,属于大量脱木素阶段,木素脱除率达到90%左右;第3阶段,160℃下保温30min至蒸煮终点,属于补充脱木素阶段,木素脱除率达到98%以上.烧碱-蒽醌法蒸煮升温初期和保温初期反应比硫酸盐法强烈;硫酸盐法脱木素的选择性好于烧碱-蒽醌法;保温时间对棉秆蒸煮是必需的;这表明棉秆脱木素反应历程与一般草类原料有很大区别.     

介绍几个工厂的较合理的草类原料碱法蒸煮曲线

蒸煮曲线的制订,应当根据蒸煮脱木素的历程来考虑。草类原料的蒸煮脱木素历程,基本上可以分为三个阶段:(1)大量脱木素阶段,即升温到100℃以前的阶段,脱除的木素大约为60—75％;(2)补充脱木素阶段,即从100℃升温到最高温度(145—160℃)的阶段,脱除的木素大约为15—30％;(3)残余木素脱除阶段,即最高温度下的保温阶段,脱除的木素大约在5％以下。其中大量脱木素阶段最为重要,在此阶段,应该保证药     

热置换自催化麦草乙醇法制浆蒸煮历程的研究

以麦草为研究对象,引入热置换洗涤工艺对自催化乙醇法制浆蒸煮历程进行研究,并在此基础上优化了洗涤工艺,对纤维分离点浆料性质进行了进一步研究。结果表明,热置换自催化麦草乙醇法制浆蒸煮保温40 min左右为纤维分离点,脱木素历程可分为两个阶段,从开始脱木素到保温40 min为大量脱木素阶段,保温40 min到60 min为残余木素脱除阶段;蒸煮保温时间应选择在60 min左右,继续延长保温时间,脱木素作用不强,而浆的得率明显降低。乙醇浆的高硬度和得率的矛盾与传统制浆方法相比显得更为突出。     

胡麻碱性亚硫酸钠—蒽醌法蒸煮机理的研究

本文研究了胡麻的原料组成,木素特性及胡麻碱性亚硫酸钠-蒽醌法蒸煮机理。 研究分析结果表明,胡麻中半纤维素主要由阿拉伯糖-葡萄糖醛酸-木糖组成。胡麻木素属GSH型,其中G>S>H;与麦草、竹子比较,胡麻木素中紫丁香基含量较高,而对羟苯基含量较少。胡麻的AS-AQ法蒸煮脱木素历程分为:(1)初始脱木素阶段,50℃升温到120℃;(2)大量脱木素阶段,120℃到165℃保温半小时;(3)补充脱木素阶段,165℃保温半小时到保温3小时。各微区木素的脱除也可分为三个阶段。碱在其中的作用,主要是使木素大分子发生某种程度的碎片化,木素的脱除主要是磺化溶出的结果。     

芦苇乙醇法制浆木素脱除规律研究

研究对比了芦苇自催化乙醇法制浆与H2O2辅助乙醇法制浆的木素脱除规律。结果表明,乙醇法制浆加入H2O2后可以加速乙醇水溶液的脱木素效率。采用扫描电子显微镜-X射线能谱仪（SEM-EDXA）测试不同蒸煮情况下纤维细胞壁中锰离子峰度发现,H2O2辅助乙醇法制浆的木素脱除速率较自催化乙醇法制浆快;自催化乙醇法制浆与H2O2辅助乙醇法制浆的细胞壁木素脱除速率规律一致：ML＋P〉S1〉S2〉S3;当保温时间大于30 min时,ML＋P层木素脱除速率远大于其他各层。     

杨木自催化乙醇法制浆及其反应历程的研究

研究了杨木自催化乙醇法制浆的保温温度、乙醇浓度、液比和保温时间等因素对成浆状况的影响规律,得出了制浆的最佳工艺条件:保温温度205℃,乙醇体积分数60%,液比1:10,保温时间2.5 h.同时研究了杨木自催化乙醇法制浆保温阶段的反应历程和反应动力学,研究结果表明:保温阶段脱木质素反应为一级反应,反应分为大量脱木质素和残余脱木质素两个阶段;在蒸煮最优条件下,大量脱木质素阶段反应速率常数为0.0128 min-1,反应活化能为47.9980 kJ/mol;残余脱木质素阶段反应速率常数为0.0038 min-1,反应活化能为78.7751 kJ/mol.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.