加碘盐中碘酸钾的稳定性讨论

目前国内生产的加碘盐所添加的碘剂主要是碘酸钾和碘化钾，由于碘化钾的稳定性差，易受食盐中水份、杂质，外界温度、空气、阳光和气象条件的影响而分解，无法保证加碘盐的质量，因此碘酸钾被选为加碘盐指定碘剂。本文论述了碘酸钾的稳定性，讨论了以四川省蓬莱黄由为原料生产的加碘盐的稳定性。本文还论及了加碘盐变色的问题。     

运用碘酸钾生产线生产碘化钾的工艺研究

通过对碘酸钾、传统碘化钾生产工艺的分析、研究,成功运用碘酸钾生产线产出了高纯度的碘化钾,为企业创造了效益.     

溴甲酚绿吸光光度法测定食盐中碘含量的研究

研究了在盐酸介质中,碘酸钾、碘化钾与溴甲酚绿的显色反应。结果表明,反应产物的最大吸收波长在364nm。在实验条件下,碘量在0～1.0×10-4mol/L内服从郎伯-比尔定律,线性相关系数R2为0.9991,摩尔吸光系数为:5.01×104L/mol.cm。该法用于加碘食盐中微量碘酸钾的测定,其RSD为1.95%～2.10%(n=6),由此建立了一个简单、方便、快速测定食盐中微量碘酸钾的新方法。     

气相色谱法快速检测粮食中10种农药多残留的研究

建立了一种粮食中农药多残留的快速检测方法.采用丙酮作为萃取剂,经过手摇振荡2 min后过滤,直接用气相色谱检测.以稻谷、小麦、玉米为基质进行添加回收试验,稻谷的添加回收率为100.8％～113.5％,RSD≤8.7％;小麦的添加回收率为97.4％～112.6％,RSD≤10.1％.玉米的添加回收率为92.6％～112.8％,RSD≤9.8％.稻谷中农药的检出限(LOD)为2.0～18.0 μg/kg;小麦中的为3.0～22.0 μg/kg;玉米中的为3.0～24.0 μg/kg.该方法简便快捷,定量准确可靠,可以满足粮食中农药多残留分析的要求.     

气相色谱法测定蛋和蛋制品中的六六六、滴滴涕

建立了蛋和蛋制品中六六六、滴滴涕残留量的气相色谱检测方法.样品经正己烷提取、浓硫酸净化,气相色谱分离后,电子捕获检测器检测,外标法定量.在5 μg/kg～20 μg/kg添加水平,回收率在75.4%～90.3%之间,变异系数在2.5%～9.1%之间.以S/N=3计算,方法最低检出限为5.0 μg/kg.结果表明,该法简便、灵敏、准确,适用于鸡蛋中的六六六、滴滴涕残留量的分析.     

浅议用碘酸钾制加碘盐

浅议用碘酸钾制加碘盐河北省黄骅盐场精制盐厂张国君关键词加碘盐，湿法加碘，干法加碘我国碘缺乏病区甚广，多年来用碘化钾作为加碘盐的加碘剂，收到了很好的社会效益。但是，由于碘化钾易挥发、不稳定、降低了碘盐的使用效果。所以，国家有关部门决定用碘酸钾代替碘化钾...     

酸奶中违禁性激素多残留同时测定方法

在多反应监测模式下采用正离子采集模式建立了酸奶中7种激素的超高效液相色谱一质谱/质谱(UPLC-MS/MS)检测方法.样品以甲醇为提取剂超声提取,经LC-C18净化,经BEH-C18(1.7 μm,2.1mm×100mm)柱分离后进行UPLC/MS/MS多反应监测模式下的定性及定量分析.7种激素方法检出限为0.011～0.05 μg/kg,定量限为0.037～0.36 μg/kg,添加水平为0.5 μg/kg时,平均回收率为72%～124%,相对标准偏差为8.0%～24%.     

液相色谱-串联质谱法检测牛奶中10种β-兴奋剂

建立了液相色谱-串联质谱同时检测牛奶中10种β-兴奋剂残留量的方法.样品经沉淀蛋白质,酸性水溶液提取, 提取液经Oasis MCX 固相萃取柱净化,LC/MS/MS方法测定.采用了Thermo Hypersil Gold (150×2.1 mm,5 μm) 色谱柱;5 mmol 乙酸铵水溶液-甲醇流动相,梯度洗脱.方法线性相关系数r均大于0.999.克伦特罗检出限为1.68 μg/kg,其余9种β-兴奋剂的检出限在0.146～0.203 μg/kg之间;克伦特罗定量限为3.37 μg/kg,其余9种β-兴奋剂的定量限在0.290～0.407 μg/kg之间.3个添加水平下,10种β-兴奋剂平均回收率在91% ～127%之间.     

面团配方及工艺条件对烧饼中丙烯酰胺形成的影响

研究了面团配方和工艺条件对烧饼中丙烯酰胺含量的影响.面团发酵的前0.5 h,丙烯酰胺含量随发酵时间的延长而增加,即从60.2μg/kg增至95.4μg/kg;但随着时间的延长,丙烯酰胺含量呈缓慢下降趋势,发酵1 h时丙烯酰胺含量降至88.5μg/kg;在面团中添加0～5%的蔗糖,烧饼中丙烯酰胺含量随蔗糖添加量的增加而增加,即从98.0 μg/kg增至139.6 μg/kg;在面团添加0～2%的食盐,烧饼中丙烯酰胺含量随食盐添加量的增加而减少,即从100.8μg/kg降至67.7μg/kg.烘烤温度-时间模式与烧饼中丙烯酰胺含量密切相关,210℃烘烤12min时丙烯酰胺含量为134.2μg/kg,而180℃烘烤20 min时丙烯酰胺含量为90.8μg/kg.在面团中减少蔗糖添加量、增加食盐添加量.并在较低温度下适当延长烘烤时间,可以将烧饼中丙烯酰胺含量控制在较低的水平.     

固相萃取-高效液相色谱法测定食品中痕量花粉红染料

本实验建立了测定食品中痕量花粉红色素的高效液相色谱方法.样品经正己烷等溶液提取,经过中性氧化铝柱净化,以甲醇和水溶液为流动相进行色谱分离,在激发波长550 nm,发射波长580 nm的荧光条件下检测.花粉红的浓度在0.5～10.0 μg/ L 范围内与其色谱峰面积的线性关系良好( r=0.999),在1、5、10 μg/kg添加水平时的回收率为56.3 %～80.1%,RSD为2.8 %～5.7%.方法的定量检出限为1.0 μg/kg.     

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