糖汁电絮凝脱色的研究

研究采用电絮凝法对糖汁进行脱色,考察了电絮凝时间、电流密度、温度、初始pH以及电极间距对糖汁脱色效果的影响。结果表明,用铝做电极材料,电絮凝法处理糖汁的最佳工艺条件为:电絮凝时间12 min、电流密度600 A/m2、温度50℃、电极间距15 mm和初始pH4～9,在此条件下糖汁的脱色率可以达到90%以上。     

电絮凝法用于处理废纸脱墨废水

采用电絮凝法处理废纸脱墨废水.探讨了电极材料、电流密度、极板间距、体系的pH值、电解时间等对废水处理的影响.结果表明,用铝为电极材料,在电流密度1.7A/dm3、极板间距10mm、体系pH5～6.5和电解时间20min的条件下,可获得良好的处理效果,废水的浊度去除率和COD去除率分别可达95%和60%.     

电絮凝法处理铬黑T染料废水的研究

采用电絮凝法处理铬黑T染料废水,通过正交试验,确定了各影响因素的顺序:电解时间>电极板间距>电解电压>初始pH>染料初始质量浓度.单因素试验结果表明,电絮凝法处理铬黑T染料废水的最佳条件:铬黑T初始质量浓度为200 mg/L、电解时间为30 min、电解电压为20 V、初始pH为5~7、电极板间距为2.5 cm,在此条件下脱色率可达94.52%.     

电絮凝法用于处理废纸脱墨废水

采用电絮凝法处理废纸脱墨废水.探讨了电极材料、电流密度、极板间距、体系的PH值、电解时间等对废水处理的影响.结果表明,用铝为电极材料,在电流密度1.7A/dm3、极板间距10mm、体系pH5-6.5和电解时间20min的条件下,可获得良好的处理效果,废水的浊度去除率和COD去除率分别可达95%和60%.     

电絮凝法处理采油污水试验研究

在自制的电解槽中,采用电絮凝法处理含聚合物的采油污水,讨论了极板间距、搅拌速度、电流密度、pH值、电解时间等因素对去除效果的影响,确定了最佳电絮凝条件,并将电絮凝同化学絮凝处理效果进行了对比。     

电化学参数对硫化黑染色废水絮凝效果的影响北大核心

为解决硫化染料染色废水的处理难题,选择六种不同金属作为阳极、石墨作为阴极,通过电絮凝技术对硫化黑染色废水进行处理,观察废水色度、电絮凝效果和电极表面腐蚀情况,确定适宜的阳极材料。在直流稳压电源体系中,以施加电压、电解时间、极板间距、初始pH为影响因子设计正交试验,探究絮凝物质量、上清液化学需氧量(COD)、色度及反应过程中电极损失率等影响因子的显著性,综合评价废水处理效果。结果表明:镁阳极可使处理后上清液色度降低,絮凝时间和极板间距对电絮凝效果影响较大。最佳电絮凝条件为:施加电压8 V,电解时间20 min,初始p H为9,极板间距为2 cm,此时废水的COD去除率为44%,色度降为90倍,电极损失率为12.23%,絮凝物质量达1.124 6 g。     

电絮凝法处理偶氮染料废水的脱色试验研究

采用电絮凝法对甲基橙模拟偶氮染料废水的处理进行研究,用正交试验确定各影响因素的主次关系为:电解时间>电解电压>初始pH>电极板间距>染料初始质量浓度,探究了各影响因素对电絮凝的影响.试验结果表明,在甲基橙初始质量浓度为40mg/L、电解时间为40 min、电解电压为25 V、初始pH为5~7、极板间距为2.5 cm的条件下,甲基橙染料废水的脱色率最高可达90.2%.     

电凝聚法处理印染废水

通过色度、CODCr去除率评估了电凝聚法对活性黑5溶液的处理效果,探讨通电时间、电流密度、电极间距、活性黑5染料溶液初始质量浓度、初始pH、电解质种类对色度、CODCr去除率的影响。结果表明:延长通电时间、提高电流密度有利于提高色度、CODCr去除率;染料溶液初始质量浓度越小,色度、CODCr去除率越高。考虑能耗因素,最适合的参数为:以氯化钠为电解质,在染料溶液初始质量浓度50 mg/L,通电时间60 min,电流密度12 mA/cm2,pH=6,电极间距20 mm时,活性黑5的色度、CODCr去除率分别为99%和65%。     

电絮凝技术应用于蔗汁脱色的初步研究

介绍了电絮凝技术用于甘蔗糖厂蔗汁脱色的试验和电絮凝技术机理。电絮凝技术作用主要体现在对蔗汁的脱色、杀菌、减少灰分残留等3个方面,在50～70℃范围研究了不同糖汁温度和电流密度下电絮凝后清汁的脱色率。结果表明:电絮凝法处理预灰汁的沉降清汁纯度提高了0.13AP,在亚硫酸法基础上脱色率提高了12.55%,电导灰分平均降低200μs/cm。电絮凝温度越高清汁脱色率越高,而电絮凝耗电量则越大。     

基于周期换向技术的靛蓝染色废水电絮凝处理

为降低极板腐蚀和电能消耗，实现对悬浮污染物的有效分离，以铁、铝金属为电极，探究周期换向技术条件下施加电压、时间、电解初始pH值等参数对电絮凝效果的影响，并检测极板腐蚀情况和溶解效率。结果表明：在周期换向电源下，施加电压25 V时，设定铁-铝电极极板间距为2 cm，废水初始pH值为5.00，经过25 min电絮凝后，废水上清液COD值为180.7 mg/L，脱色率达99.00%，絮凝率为86.10%，显示出优异的电絮凝效果。与直流电源相比，周期换向电化学体系中，电极腐蚀及钝化现象得到有效缓解，铁、铝电极的损失率仅为0.6%，溶解效率高于80.0%;COD去除比能耗为0.39，相当于直流电源的27.3%。     

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.