特殊医学用途全营养配方食品中β-羟基-β-甲基丁酸钙的含量测定

目的 通过优化样品前处理和色谱条件,建立高效液相色谱-紫外检测法测定特殊医学用途配方食品中β-羟基-β-甲基丁酸钙含量的分析方法。方法 样品用0.1 mol/L的盐酸溶液提取,经离心、上清液过滤后,以0.05 mol/L磷酸二氢钾溶液(pH3.0)-乙腈(95:5)为流动相,采用Caprisil C18-P色谱柱(250 mm×4.6 mm,5 μm)分离,紫外检测器检测,外标法定量。结果 β-羟基-β-甲基丁酸钙在0.0947~0.9474 mg/L的浓度范围内与峰面积呈现良好的线性关系,相关系数R=0.9998,定量限为0.28 μg/g,检出限为0.09 μg/g。加标回收率在97.08%~101.22%之间,相对标准偏差为1.20%。结论 该方法操作简单,重复性好,结果可靠,可满足特殊医学用途配方食品中β-羟基-β-甲基丁酸钙的含量测定,为产品的质量控制提供有力的技术支撑,并填补国内特殊医学用途配方食品关于β-羟基-β-甲基丁酸钙质量检测的空白。     

特殊医学用途婴儿配方食品中生物素含量的测定

本研究建立了超高效液相色谱-串联质谱法测定特殊医学用途婴儿配方食品中生物素含量的分析方法。样品经0.2 mol/L磷酸121℃水解30 min提取,并通过生物素免疫亲和柱净化后,采用Acquity UPLC BEH C18(100 mm×2.1 mm,1.7μm)色谱柱进行分离,以乙腈-0.1%甲酸溶液为流动相进行梯度洗脱,经电喷雾电离串联质谱在多离子反应监测(MRM)模式下进行测定,内标法定量。在最优化条件下,生物素在0.50~50.00 ng/mL范围内线性关系良好(R²=0.9986),方法检出限为0.75μg/100 g。特殊医学用途婴儿配方食品中生物素相对标准偏差在0.42%~4.77%之间,不同添加浓度回收率为97.27%~102.06%。该方法具有样品处理操作简单,灵敏度高,分析周期短等优点,可以满足特殊医学用途婴儿配方食品中生物素含量的测定,可为企业质量控制和政府监管提供有力的技术支撑。     

液相色谱-质谱联用法检测特殊医学配方食品中泛酸的含量

目的 建立一种快速准确高效的方法检测特殊医学配方食品中泛酸的含量。 方法 试样中的泛酸, 用酸碱沉淀杂质, 水超声提取, 经Agilent Eclipse XDB-phenyl柱分离, 以甲醇和0.1%甲酸溶液为流动相, 梯度洗脱, 流速为0.4 mL/min, 柱温40 ℃, 采用液相色谱-质谱法检测。结果 泛酸在0.4~7.6 ?g/mL的浓度范围内, 线性关系良好, 相关系数r均大于0.99。平均回收率在90.79%~106.93%之间, 相对标准偏差(relative standard deviation, RSD)为6.3%, 且在6 h内含量保持稳定, 精密度的相对标准偏差(RSD)为1.5%。结论 液质联用法能准确快速高效检测特殊医学配方食品中的泛酸含量, 能对特殊医学用途配方食品中泛酸的含量起到质量控制的目的。     

超高效液相色谱-同位素稀释质谱法测定食品中的泛酸

目的 建立一种快速准确测定食品中泛酸含量的方法。方法 样品中的泛酸用水提取,经乙酸锌溶液和亚铁氰化钾溶液除杂后,以乙腈和0.1%甲酸溶液为流动相,通过Waters HSS T3 C18柱(2.1 mm×100 mm,1.7 μm)梯度洗脱分离,流速0.3 mL/min,进样量2 μL,柱温35 ℃,用串联质谱检测,同位素内标法定量。结果 泛酸在10-600 μg/L浓度范围内具有良好的线性关系,相关系数为0.9999,方法检出限为0.025 mg/100 g,定量限为0.075 mg/100 g,精密度的相对标准偏差为1.6%~1.8%,3个加标水平的回收率在92.6%~105%之间,相对标准偏差为1.9%~3.8%。该方法与微生物法相比结果无明显差异,且测定时间短,与高效液相色谱法相比抗干扰能力强。结论 超高效液相色谱-同位素稀释质谱法操作简单,快速准确,适用于多种食品中泛酸的测定。     

高效液相色谱法测定强化食品中维生素B6的含量

目的 建立了一种高效液相色谱法检测强化食品(婴幼儿配方食品、婴幼儿谷类辅助食品和功能饮料)中维生素B6方法。方法 利用Eclipse Plus C18(5 μm, 4.6 mm×250 mm)色谱柱, 流速1 mL/min, 流动相: 甲醇-(0.2 g/L辛烷磺酸钠, 体积分数为0.25%的三乙胺溶液, 利用乙酸调节pH=3.2±0.1)(V:V=21:79), 进样量 10 μL, 柱温30 ℃实现了对吡哆醛、吡哆醇和吡哆胺3种组分的分离; 在激发波长293 nm, 发射波长395 nm的条件下实现了对这3种组分的检测。结果 吡哆醛、吡哆醇和吡哆胺在0.1~1.0 μg/mL范围内均表现出良好的线性关系, 3种组分的相关系数均大于0.999, 检出限为0.01~0.02 mg/100 g, 定量限为0.03~0.05 mg/100 g, 均满足现行国标要求。3种维生素B6在添加水平为0.05、0.20和0.60 mg/100 g时的加标回收率为89.6%~107.1%, 相对标准偏差(n=6)为1.3%~7.0%。结论 该方法操作简便, 准确度和精密度高, 能够用于对多种常见强化食品中3种维生素B6的检测     

伏安极谱法测定兔毛皮中可萃取甲醛含量的研究

优化了伏安极谱仪测定甲醛含量的参数,测定了方法的线性范围和精密度,优选了萃取兔毛皮中甲醛的溶液和萃取温度,并对测定结果的精密度和回收率进行了评估,将测定结果与国标法测定结果进行了对比。实验结果表明:伏安极谱仪的测定甲醛的最适条件为:动态滴汞方式,高纯氮气通气时间600 s,富集时间60 s;甲醛浓度在400μg/L~200 mg/L时有良好的线性关系;精密度实验的相对标准偏差(n=10)为1.38%;用0.05 mol/L的氢氧化锂溶液在35℃萃取兔毛皮样品20 min,兔毛皮样品中甲醛含量为46.2 mg/kg,样品的重复性实验结果相对标准偏差(n=8)为2.15%;加标回收率在95.4%~103%之间;测定结果与国标法测定结果相比,相对偏差为1.44%;说明采用伏安极谱法测定兔毛皮中的甲醛含量结果准确、检测限低、重现性好。     

原子吸收光谱法测定特殊医学配方食品中钾元素分析条件的优化

目的 建立一种测定特殊医学配方食品中钾元素含量的原子吸收光谱法。方法 该方法采用钾钠混标, 研究工作电流、燃烧器高度、光谱通带、燃气流量等操作条件对测定特殊医学用途配方食品中钾含量的影响, 确定最佳测试条件。结果 优化后测试条件为: 采用钾钠混标, 不加入铯盐, 燃烧头偏转30?, 燃烧器高度为3 mm, 燃气流量为0.9 L/min, 空心阴极灯电流为8 mA, 光谱通带为0.6 nm, 样品测定结果为586.22 mg/100 g, 检出限为0.019 mg/L, 回收率为96.8%~98.1%, 相对标准偏差为0.47%。结论 本方法操作简单、准确度、精密度、灵敏度高, 能较好的满足特殊医学配方食品中钾元素测定要求。     

HPLC法测定特殊医学用途婴配食品中视黄醇棕榈酸酯和视黄醇醋酸酯

采用正相高效液相色谱法测定特殊医学用途婴配食品中视黄醇棕榈酸酯和视黄醇醋酸酯的含量。采用氨基柱(150mm×4.6mm,5.0μm)为色谱柱,流动相:正己烷-25%叔丁基甲醚正己烷(体积比955),等梯度洗脱;流速:1.0mL/min,柱温:30℃;进样量:50μL;紫外检测器波长:325nm。结果表明:视黄醇棕榈酸酯保留时间为3.5min,视黄醇醋酸酯保留时间为6.0min,在0.05~10.0μg/mL呈线性相关(R2=0.999 9),检出限分别为2.0,2.5μg/100g。特殊医学用途婴儿配方食品中视黄醇棕榈酸酯含量为0.0~817.0μg/100g,精密度为0.9%~9.4%,视黄醇醋酸酯含量为0.0~8 683.0μg/100g,精密度为3.3%~6.3%,不同添加浓度回收率为81.0%~90.0%。该方法简单、快速、准确、精密度高,分离度好。     

酶水解-液相色谱法测定婴幼儿食品中的色氨酸

利用酶解水解法,建立了婴幼儿配方乳粉(以下简称乳粉)和特殊医学用途婴儿配方食品(以下简称为医学食品)中游离和总色氨酸的高效液相色谱检测方法。样品经蛋白酶水解后,经C18色谱柱(150 mm×4.6 mm, 3.5μm)分离,以甲醇-0.1%乙酸溶液作为流动相等度洗脱,紫外检测器串联荧光检测器检测,外标法定量。结果表明:在质量浓度为0.2～100μg/mL范围内线性关系良好(r2=0.9999)。添加质量分数在100,500,1000 mg/100 g时,色氨酸的回收率介于99.0%～105.3%之间。色氨酸的检出限为1.5 mg/100g,定量限为5 mg/100 g。本方法操作简便,重现性好,可应用于市售乳粉和医学食品中色氨酸含量的测定,填补了检测标准缺失的空白。     

运动营养食品中β-羟基-β-甲基丁酸钙的含量测定

文章旨在建立高效液相色谱法测定运动营养食品中β-羟基-β-甲基丁酸钙(Calcium-β-hydroxy-β-methylbutyrate,HMB-Ca)含量的方法。取样品于50 mL容量瓶中，加入0.1 mol/L盐酸溶液约40mL，超声处理30 min，用0.1 mol/L盐酸溶液定容至50 mL，用0.45μm滤膜过滤，经Phenomenex Gemini C₁₈色谱柱(250 mm×4.6 mm,5μm)分离，以0.01 mol/L庚烷磺酸钠溶液:甲醇(95:5,V:V)为流动相等度洗脱，流速0.8 mL/min，柱温30℃，进样量10μL，二极管阵列检测器214 nm波长采集数据，外标法定量。HMB-Ca在5～1000 mg/L浓度范围内线性良好，相关系数R2为0.99999。3个浓度水平的平均加标回收率在96.9%～98.1%，相对标准偏差(n=6)为0.87%～1.84%，精密度的相对标准偏差(n=6)为0.32%，方法检出限为0.020 g/100 g，定量限为0.050 g/100 g。该方法操作简便、灵敏度高，具有良好的准确度和精密度，适用于运...     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

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.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.