磷钼酸催化法制备某些缩醛(酮)的研究

缩醛（酮）合成反应的传统催化剂为无机强酸,但由于副反应多、腐蚀性强和易污染环境等缺点,其使用受到限制．用磷钼酸为催化剂,通过醛（酮）与乙二醇直接反应得到了三种缩合产物．对影响反应的诸因素进行研究,结果表明,用磷钼酸作催化剂,用量小,活性高,产品收率较高,且重复使用性能较好．     

蔗糖发酵过程中无机磷含量的变化研究

无机磷与钼酸能形成磷钼酸络合物，该络合物能被还原剂α-1，2，4-氨基萘酚磺酸钠还原成钼蓝，用分光光度计确定蔗糖发酵前后无机磷的含量，观察发酵过程中无机磷的消耗。发现高浓度的磷酸盐会对微生物合成具有抑制和阻遏作用，无机磷含量的减少使葡萄糖磷酸化减慢，进而也影响糖酵解速度。研究表明在pH为6、温度为37℃、无机磷浓度为5g/L左右，发酵最佳。     

氧化亚铜还原杂多酸-磷钼酸钼蓝比色法测定食品还原糖的探讨

用氧化亚铜还原杂多酸—磷钼酸钼蓝比色法测定食品中的还原糖,设备简单操作快速,回收试验及重现性测定结果满意,其色泽稳定1小时不变。证明此法的引用是成功的。     

淀粉磷酸酯结合磷分析

本文提出了用碳酸钙干灰化和磷钼酸奎啉容量法分析淀粉磷酸酯结合磷方法。实验表明，提出的方法在分析结果上与国际标准ＩＳＯ３９４６－１９８２的方法是一致的。氧化锌代替碳酸钙干灰化分解淀粉磷酸酯同样可行。     

钼酸铋的研究进展

钼酸铋是近年来催化剂领域中新发现的一种新型的光催化剂,随着环境污染越来越严重,具备较高光催化活性的钼酸铋引起了科研人员的重视。本文综述了钼酸铋光催化剂的结构、光催化机理、结构与设计、应用及其改性研究。     

食品添加剂植酸钠中无机磷含量测定研究

建立了一种食品添加剂植酸钠中无机磷含量的测定方法。本文对经典钼黄法进行改进,采用"三氯化铁去除基质效应"再用钼黄法测定无机磷含量,首先向植酸钠样品溶液中加入三氯化铁溶液,使其形成沉淀,高速离心弃去沉淀后再加入钒钼酸铵溶液,生成黄色的磷钒钼酸配合物,用分光光度计在420nm处测其吸光值,再根据标准曲线计算样品中无机磷含量。结果表明,当无机磷添加浓度为0.02%～0.08%时,回收率范围在99.0%～102.48%之间,相对标准偏差在1.03%～1.16%之间,方法学指标满足《GB/T 27404-2008实验室质量控制规范食品理化检测》的要求。     

钼酸银抗菌纸的制备及其抗菌性能

制备钼酸银抗菌纸,并对其抗菌性能进行研究。抗菌剂采用表面喷涂和浆内填加两种方式与纸浆纤维结合;选择大肠杆菌、黑曲霉菌、金黄色葡萄球菌三种代表性菌种检测其抗菌性能。研究结果表明:钼酸银抗菌纸对以上三种菌种均具有一定的抑制效果,对金黄色葡萄球菌的抗菌效果最为明显;随钼酸银浓度升高,抗菌效果增强;随时间延长,对霉菌抗菌效果减弱,但对大肠杆菌、金黄色葡萄球菌抗菌效果下降不明显。     

肉制品的分析方法(二)

<正> 八、磷酸盐测定磷酸盐时,先将不完全干燥的样品灰化,然后使磷酸盐水解为正盐,再以磷钼酸喹啉形式离析出来.1.原理:首先,将磷酸盐生成磷钼酸(有柠檬酸盐存在时),然后磷钼酸再与碱、喹啉形成磷钼酸喹啉.柠檬酸能与铵离子络合,阻止磷钼酸铵沉淀的出现.最初,测定时需要制备种两溶液,以生成磷钼酸喹啉沉淀;即柠檬酸—钼酸溶液和喹啉溶液.后来使用了丙酮,使这两种溶液合二为一,即可用一种试剂作为沉淀剂.我们把该沉淀剂称为喹钼柠酮试剂,它是由混合物中的喹啉、钼酸盐、柠檬酸盐和丙酮的英文名称的字头命名的.     

BiPMo12O40的水热合成、表征及其对甲基橙光催化性能的研究

以磷钼酸和硝酸铋为原料,采用水热合成法制备磷钼酸铋(样品1);此外,在相同的合成过程中分别加入十六烷基三甲基溴化铵(CTAB,样品2)和加入十二烷基硫酸钠(SDS,样品3)。红外光谱仪和X射线粉末衍射表征说明3种样品都保持了磷钼酸的Keggin型结构,样品2和样品3分别还有CTAB和SDS的特征峰。因此推测3种催化剂的分子式分别为BiPMo_(12)O_(40)、BiPMo_(12)O_(40)·nCTAB和BiPMo_(12)O_(40)·nSDS。分别在无光、紫外光和可见光的条件下,将磷钼酸铋作为光催化剂对1mg/L的甲基橙溶液进行光催化性能研究,结果表明样品2在可见光条件下具有良好的光催化活性。     

磷酸酯表面活性剂中微量无机磷的实时测定

利用磷钼酸蓝离心分光光度法,对磷酸酯表面活性剂中的微量无机磷进行直接测定,该方法在大量有机磷酸酯存在时对无机磷的测定无干扰,样品无需预处理,回收率为95%～103%.可监测反应釜中的磷化剂含量,适用于对生产过程的实时监控.     

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.