绿原酸、异绿原酸A抑制亚硝化反应研究

研究绿原酸、异绿原酸A抑制亚硝化反应的能力及最适作用条件。结果表明,绿原酸类物质清除亚硝酸盐及阻断亚硝胺合成的效果随浓度、反应时间和温度的升高逐渐增强,随pH值的升高而降低。清除亚硝酸盐的最适质量浓度5μg/μL,pH3.4,反应时间40 min,反应温度47℃;阻断亚硝胺合成的最适质量浓度3μg/μL,pH2.8,反应时间20 min和反应温度47℃;抑制亚硝化反应最适条件为样液质量浓度5μg/μL,pH 2.8,反应时间40 min,温度47℃。在抑制亚硝化反应方面,绿原酸与VC效果相当,均弱于异绿原酸A,三者均弱于芦丁。绿原酸和异绿原酸A都有较好的抑制亚硝化反应的能力,且随反应体系环境的变化而存在差异。     

甲霜灵根施对土壤硝化作用的抑制效应

检测了甲霜灵在不同浓度、施入土壤后不同时间对亚硝化细菌和硝化细菌数量的影响及土壤pH值和硝化强度的变化.结果表明甲霜灵对土壤硝化作用有一定的抑制效应,在试验条件下,每千克土壤含25mg甲霜灵时,在用药后4～8周内都表现出对硝化作用的抑制效应.     

迷迭香酸对胰岛素硝化的抑制作用

目的：采用化学体系考察迷迭香酸（rosmarinic acid,RA）对胰岛素硝化的保护作用。方法：采用比色法和非变性聚丙烯酰胺凝胶电泳检测迷迭香酸对胰岛素和过量过氧亚硝基阴离子（ONOO－）反应的影响。结果：胰岛素可以和ONOO－反应生成硝化胰岛素,在396 nm波长处有最大吸收峰。RA可浓度依赖性地抑制ONOO－所致的胰岛素硝化作用,但对已经硝化的胰岛素没有影响。结论：RA通过清除ONOO－抑制胰岛素的硝化作用。     

不同类型污泥接种源培养的好氧颗粒污泥脱氮性能比较

分别以活性污泥和厌氧颗粒污泥培养的好氧颗粒污泥为对象，对成熟污泥颗粒的脱氮性能进行了比较研究。结果表明，颗粒污泥驯化成熟之后，对氨氮的去除效果维持在95％左右，与其污泥接种源没有明显的相关关系；对一个降解周期内氮的形态分析表明，在颗粒污泥存在的反应器内发生了同步硝化反硝化。     

贵长猕猴桃多酚抗氧化及抑制亚硝化作用研究

对贵长猕猴桃多酚的抗氧化活性及抑制亚硝化作用进行研究。采用超声辅助乙醇浸提的方法提取猕猴桃多酚,以没食子酸为标准物质来测定提取物的多酚含量。通过对DPPH、羟基自由基清除率及总还原力的测定,评价了贵长猕猴桃多酚的抗氧化性。采用紫外分光光度法,测定了贵长猕猴桃多酚的亚硝酸盐清除率和亚硝胺合成阻断率,以评价其对亚硝化反应的抑制能力。结果表明,贵长猕猴桃中多酚含量为(302.87±7.01)mg GAE/100 g FW。贵长猕猴桃多酚具有较强的抗氧化活性。随质量浓度的增大,其对DPPH自由基、羟基自由基的清除能力和还原能力均显著增加,呈现出明显的剂量依赖效应。其对DPPH自由基、羟基自由基清除活性的半数抑制浓度(IC_(50))分别为0.22、0.45 mg/mL。在模拟人体胃酸条件下(pH3.0、温度37℃),贵长猕猴桃多酚能有效清除亚硝酸盐及阻断亚硝胺合成。随着质量浓度增加,清除率和阻断率先增大最后趋于平稳。其IC_(50)分别为0.077、0.082 mg/mL,优于阳性对照Vc,展现出一定的癌症预防功效。贵长猕猴桃多酚具有良好的抗氧化活性及抑制亚硝化反应的作用。     

一体化生物流化床-生物滤池处理高氨氮印染废水

采用一体化生物流化床-生物滤池反应器对纺织印染企业实际生产废水进行处理,研究溶解氧和停留时间对废水处理效果的影响。结果表明,溶解氧过低会导致亚硝酸盐的累积,不利于氨氮的硝化和反硝化去除;当溶解氧质量浓度为1.5~2.0 mg/L时,出水的亚硝酸盐浓度高,氨氮和总氮的去除率低;当溶解氧质量浓度为2.5~3.8 mg/L时,氨氮和总氮的去除率提高。延长水力停留时间,有利于提高COD和氨氮的去除效果,但停留时间过长,水中有机物减少,反硝化作用会受到抑制,致使总氮去除率降低。     

氯化钠和铬鞣剂对厌氧微生物毒性的研究

用甲烷气体的产气速率来衡量厌氧颗粒污泥的产甲烷活性 ,以厌氧颗粒污泥处理含不同浓度氯化钠和铬鞣剂的废水 ,研究氯化钠和铬鞣剂对厌氧颗粒污泥的毒性。研究结果可为制革废水的厌氧处理提供参考依据。     

DT-F 609加脂剂生物降解性研究

DT-F 609加脂剂作为基质,采用COD30法、呼吸曲线法、BOD5/CODCr,法对其生物降解性进行了研究.结果表明,当基质质量浓度为0～1000 ms/L时,随着基质质量浓度的增大,基质的生物降解性逐渐变好,当pH为7.2,污泥质量浓度为1000 mg/L,不外加NaCl,基质质量浓度为750 mg/L和1000 mg/L时,基质的最终生物降解率分别为95.2%和96.5%.pH、盐度、污泥浓度对基质的生物降解性均有明显影响.经试验筛选,基质生物降解的最佳pH为11,盐度为0.5%,污泥质量浓度为1500～2000 mg/L.     

采用好氧颗粒污泥工艺处理亚铵法制浆中段废水

针对亚铵法制浆中段废水的特点和好氧颗粒污泥工艺,提出了采用好氧颗粒污泥工艺处理亚铵法制浆废水,并对其进行可行性分析.分析表明,好氧颗粒污泥工艺在降解CODCr、去除NH3-N方面具有明显优势.文中还分析了高浓度硫酸盐、亚硫酸盐对该工艺的抑制作用,并提出了消除抑制的方法.     

nZVI对好氧颗粒污泥短期冲击性影响研究

本研究采用批次试验,考察了不同nZVI浓度对好氧颗粒污泥性能的冲击影响。结果表明,nZVI投加量由0 mg/L增至25 mg/L时,好氧颗粒污泥对NH4+-N的去除率显著增强;nZVI浓度为5 mg/L时,好氧颗粒污泥对出水NH4+-N及TN的去除率最高,分别较对照组提高22.75%和51.77%。污泥氨氧化速率的测定结果表明:当nZVI的投加量为5 mg/L时,好氧颗粒污泥氨氧化速率最高,促进作用最明显;当nZVI投加浓度为25 mg/L时,好氧颗粒污泥分泌的LB-EPS含量最高,而TB-EPS含量最低;当nZVI的投加量从0 mg/L提高至50 mg/L时,好氧颗粒污泥对nZVI的吸附比例逐渐升高。扫描电镜(SEM)结果表明:好氧颗粒污泥表面吸附了大量nZVI,造成微生物菌群中丝状细菌大量减少,影响了污泥表面的微生物生态。     

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.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status