毛细管电泳-电化学方法检测黄酒中多酚物质

采用毛细管电泳-电化学检测法(CE-ED)同时分离测定了黄酒中表儿茶素、芦丁、金丝桃甙、山萘酚、绿原酸、槲皮素等多种生物活性成分的含量.考察了运行缓冲液酸度和浓度、分离电压、氧化电位和进样时间等实验参数对分离、检测的影响.在最优化条件下,以300 μm碳圆盘电极为检测电极,检测电位为 950mV(vs.SCE),-40mmol/L硼砂的运行缓冲液(pH9.0)中,上述各组分在15min内可基本实现基线分离.各组分浓度与峰电流在3个数量级范围内呈良好线性,检测下限(S/N=3)分别为3.90x10-5g/L、8.09x10-5 g/L、2.96x10-5g/L、3.98x10-5g/L、1.46x10-4g/L和8.59x10-5g/L.     

毛细管电泳检测苦荞芽中的黄酮类化合物

用毛细管电泳-电化学检测的方法分析了苦荞麦芽中黄酮类物质,测定了表儿茶素、芦丁、槲皮素的含量。以直径为300μm的碳圆盘电极为工作电极,50 mmol/L硼砂溶液(pH=8.5)为运行缓冲液,对上述3组分的分离检测条件进行优化研究。在优化条件下,3组分可在12 min内完全分离,检出限分别为1.83×10-7,2.9×10-8,1.00×10-7g/L。并运用此法对自助生产的两种苦荞麦芽样品中的黄酮类物质进行跟踪测定,研究了萌发时间对其中营养成分的影响。     

毛细管电泳安培检测法快速测定巧克力中的香兰素

运用毛细管电泳安培检测法研究了巧克力中香兰素的快速测定方法,研究了电极电位、缓冲液的浓度和pH、分离电压以及进样时间等因素对分离测定的影响。在30mmol/L的硼砂(pH9.24)运行缓冲液中,施加15kV的分离电压及 0.65V(vs.SCE)的电极电位条件下,铜电极对香兰素有很好的响应。香兰素在5.0×10-6～1.0×10-3g/mL范围内存在较好的线形关系,检测限为3.87×10-7g/mL(S/N=3)。对实际样品的测定,回收率为96.5%～102.8%,结果令人满意。     

花生衣多酚物质H PLC分析及表儿茶素、儿茶素含量测定

用高效液相色谱法(High Performance Liquid Chromatography,HPLC)法分析白、红两种花生衣中几种重要多酚物质并测定其中表儿茶素与儿茶素含量。色谱分析采用shim pack VP-ODS C-18反相色谱柱分离,流速为1.0 mL/min,柱温30℃。表儿茶素、儿茶素、绿原酸、鞣酸及没食子酸以乙腈-0.5%乙酸(10∶90,体积比)为流动相,分析波长为280 nm;槲皮素与芦丁以甲醇-0.5%乙酸(45∶55,体积比)为流动相,分析波长为360 nm。实验结果表明,白、红两种花生衣中均含有表儿茶素、绿原酸、槲皮素及芦丁。红花生衣中还含有少量儿茶素,其中表儿茶素含量比儿茶素高约7倍多。红花生衣中表儿茶素含量略低于白花生衣中含量。     

差示脉冲溶出伏安法测定皮蛋中铅含量

目的:建立一种快速、准确测定皮蛋中铅含量的方法。方法:采用LK98电化学微机分析系统,优化试验参数,如电解质浓度、pH值、电沉积电位以及脉冲间隔等。结果:线性范围为1×10-5￣7×10-5mg/mL,检出限为1×10-7mg/mL,RSD为3.5%。结论:该方法简便、快速、灵敏度高、重现性好、准确可靠。     

高效毛细管电泳法对5 个产地苦荞中黄酮类化合物的检测

采用高效毛细管电泳法,分别对5 个不同产地苦荞中黄酮类化合物进行检测。电泳条件：10 mmol/LNa2B4O7-H3BO3缓冲溶液,pH 9.3,检测波长218 nm,分离电压25 kV。在该条件下,表儿茶素、芦丁、山奈酚和槲皮素4 种黄酮类化合物在7 min内得到分离,线性范围分别为0.03～0.54、0.05～0.97、0.03～0.63、0.04～0.90 mg/mL,相关系数为0.992 3～0.998 7,最低检出限分别为5.33×10－6、1.80×10－5、2.51×10－5、1.24×10－5 mg/mL（RSN=3）,平均回收率在95.5%～104.7%之间,相对标准偏差不大于3.66%。结果表明：该方法准确可靠,可用于苦荞中黄酮类化合物的检测。     

HPLC法测定菊苣中芦丁、槲皮素和山柰酚含量

建立HPLC法同时测定维药菊苣茎、根、种子总黄酮提取液中芦丁、槲皮素和山柰酚含量的方法。用安捷伦HC-C_(18)柱(250 mm×4.6 mm, 5μm)色谱柱,流动相为0.1%乙腈(A)-磷酸(B)(50︰50, V/V),流速0.8 mL/min,检测波长365 nm,柱温30℃。结果表明,芦丁、槲皮素和山柰酚分别在2.0～20μg/mL (r~2=0.999 9), 0.5～40μg/m L (r~2=0.999 8)和0.5～60μg/m L (r~2=0.999 1)浓度范围内呈现良好线性关系,加标回收率(n=3)分别为97.7%(RSD=1.89%), 97.3%(RSD=1.01%)和102.6%(RSD=0.33%)。菊苣茎中芦丁含量为116.3×10~3μg/kg,槲皮素为122.4×10~3μg/kg,山柰酚为32.7×10~3μg/kg;菊苣根中存在芦丁,含量为82.0×10~3μg/kg;菊苣子中存在芦丁和槲皮素,芦丁含量为85.0×10~3μg/kg,槲皮素为45.3×10~3μg/kg。该方法简便、快速、有效、灵敏、准确,具有良好回收率,可作为该植物的定量分析方法,试验结果可为以后菊苣资源的开发利用提供依据。     

毛细管电泳电化学发光法检测银杏叶中的芦丁

建立了芦丁的毛细管电泳电化学发光(CE-ECL)快速分离检测方法。将芦丁与五种仲胺进行衍生反应得到叔胺类化合物,先进行紫外扫描筛选,再将进行CE-ECL检测。银杏叶样品采用70%乙醇水溶液超声波辅助提取。考察检测电位、检测池缓冲液和运行缓冲液的浓度和pH值、进样电压、分离电压和时间等因素对芦丁分离检测的影响。在最佳实验条件下,芦丁在5 min内实现分离。该方法的线性范围为0.002~2μg/mL,回归方程为y=1958.4x+7600.4,相关系数为0.994,检出限为0.0004μg/mL。对0.2μg/mL芦丁标准溶液衍生物进行7次检测,其迁移时间、峰高和峰面积的RSD分别为1.1%、1.2%和2.0%。此方法应用于银杏叶中芦丁的检测,加标回收率在92%~103%之间。     

反相高效液相色谱法测定苦荞中的芦丁和槲皮素

目的:建立一种苦荞黄酮中芦丁和槲皮素含量的测定方法。方法:分别以芦丁和槲皮素为标品,采用KromasilC18反相柱(4.6mm×300mm,5μm),分别测定水解和未水解苦荞黄酮样品中芦丁和槲皮素的含量。结果:在流动相为0.4%磷酸-甲醇(体积比为40∶60)、检验波长358nm、进样速度1.0mL/min、柱温20℃条件下,测定的芦丁含量的线性范围为0.025～0.125g/L(r=0.9993),槲皮素含量的线性范围为0.008～0.256g/L(r=0.9995)。槲皮素的加样回收率99.9%,变异系数为1.50%(x,n=5);芦丁的加样回收率98.5%,变异系数为1.16%(x,n=5)。水解样中槲皮素含量为(194.7±4.22)mg/g,未水解样中槲皮素含量为(8.96±0.26)mg/g,芦丁含量为(83.84±3.29)mg/g,变异系数(x,n=3)分别为:2.17%、2.90%和3.92%。结论:该方法简便、快速、准确,可用于苦荞黄酮中芦丁和槲皮素的含量测定。     

微乳液相色谱法对蓝莓叶黄酮类化合物的分离和测定

目的：利用微乳液相色谱分离并测定蓝莓叶中儿茶素、芦丁、山柰酚、槲皮素和杨梅酮5 种黄酮成分。方法：从表面活性剂、助表面活性剂、pH值、有机相4 个方面对微乳液相色谱分离蓝莓叶黄酮的条件进行优化。结果：分离蓝莓叶黄酮的最优条件为：使用2.5%聚氧乙烯（23）月桂醚作为表面活性剂,8%正丁醇为助表面活性剂,0.8%乙酸乙酯为有机相,0.5%乙酸调节体系pH值为3.2,在以上条件下蓝莓叶黄酮在20 min内能够得到有效分离。结论：蓝莓叶中提取的黄酮类化合物含有儿茶素9.76 mg/g、芦丁13.12 mg/g、山柰酚31.04 mg/g、槲皮素26.42 mg/g、杨梅酮20.30 mg/g。     

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.