尼龙餐厨具在酸性食品模拟物中蒸发残渣迁移 行为的研究

考察了在不同使用条件下,尼龙餐厨具在酸性食品模拟物中的蒸发残渣量,并得出迁移规律：在酸性食品模拟物中,蒸发残渣随温度的升高和接触时间的延长而增加,随使用次数的增加而减少。     

尼龙餐厨具在酸性食品模拟物中蒸发残渣迁移行为的研究

目的研究尼龙餐厨具在酸性食品模拟物中蒸发残渣的迁移行为。方法在一定的时间和温度条件下,采用全浸没法将样品于4%乙酸模拟物中浸泡提取,浸泡结束后将4%乙酸浸泡液蒸干恒重后称重,计算蒸发残渣量。结果浸泡温度越高,4%乙酸蒸发残渣量越大,浸泡时间越长,4%乙酸蒸发残渣量也越大。结论在酸性食品模拟物中,蒸发残渣随温度的升高和接触时间的延长而增加,从而对于消费者的健康造成潜在的危害。     

基于差示扫描量热法的大豆原油掺伪 鉴别方法的建立

目的应用差示扫描量热仪(DSC)和油脂氧化稳定性测试仪(OSI)测试掺伪大豆原油的氧化稳定性(以诱导氧化时间表示),从而建立大豆原油掺伪的分析鉴别方法。方法设定OSI仪的氧化温度为110℃,氧气流量为20 L/h,DSC的氧化温度为110、120、130℃,氧气流量为50 m L/min,选择最佳氧化温度。记录各方法的诱导氧化时间。结果 DSC的诱导氧化时间随氧化温度提高不断缩短,确定130℃为DSC方法最佳氧化温度,不同比例掺伪大豆原油的OSI法的诱导氧化时间为320~495 min,DSC法诱导氧化时间为40~80 min。随着掺伪浓度增大,诱导氧化时间不断缩短。OSI法的掺伪检出限为掺伪浓度5%,DSC法的掺伪检出限为掺伪浓度10%。两种方法具有显著的正相关性:To(OSI110)=5.2480To(DSC130)+77.6799,r=0.9951。结论两种方法均可用于大豆原油掺伪鉴别,但DSC方法用量小,检测时间短,更适用快速鉴别。     

硼酸锌/氢氧化铝对聚氯乙烯纺织结构材料阻燃及稳定性的影响

为改善聚氯乙烯（PVC）纺织结构材料的阻燃、抑烟、防熔滴等性能,采用无机阻燃剂硼酸锌和氢氧化铝协同作用制备阻燃PVC纺织结构材料。利用极限氧指数仪、烟密度仪、热重分析仪、扫描电子显微镜分析了硼酸锌和氢氧化铝复配对PVC纺织结构材料性能的影响。结果表明：硼酸锌和氢氧化铝复配阻燃PVC纺织结构材料具有优异的阻燃性、抑烟性、防熔滴性,随着硼酸锌含量的增加,抑烟效果更佳;老化处理对PVC稳定性存在一定程度的影响,其极限氧指数值随热氧老化时间的延长先增加再降低,且随光氧老化时间的延长而增加。     

碱性介质对柔性复合材料界面粘接性能的影响

在50℃、100℃和10%NaOH溶液中对柔性复合材料进行了热老化性实验,测定了DSC曲线、吸湿率及层间剥离性能.结果表明,碱溶液介质老化主要发生在材料的无定性区,在老化前期复合材料的吸湿与Fick扩散相似,但后期吸湿率略有下降;层间剥离性能随老化时间的延长出现下降趋势,且温度有加速老化的作用.     

流通过程对大目金枪鱼肉色稳定性与氧化性能的影响

目的:模拟大目金枪鱼的冷断链流通过程,分析流通期间的温度波动对大目金枪鱼肉色稳定性与氧化性能的影响。方法:以红度值、硫代巴比妥酸值(TBA)、肌红蛋白氧化态、高铁肌红蛋白还原酶、总酚浓度(TPC)、铁离子抗氧化能力(FRAP)等指标共同表征温度波动对其品质影响,并作指标相关性比较与动力学分析。结果:随着流通过程中的温度变化与流通时间的延长,冷链组样品在-55℃的色泽稳定性及氧化性能均几乎不发生变化,断链流通组样品由于温度波动而变化明显,且L2组样品变化最显著,其在流通末期红度值为2.43,鱼体脂肪氧化高达82.56%。氧合肌红蛋白伴随高铁肌红蛋白含量的增加而显著下降,酶活力受温度变化而对色泽产生影响,样品的红度值对温度变化反应敏感。所有样品在流通末期的TPC值均显著下降35%,FRAP值则分别降低16.15%和48.21%,64.78%(P<0.05)。相关性分析表明红度值可作为快速判断鱼肉品质变化的重要指标,该指标同TPC、FRAP、TBA值、肌红蛋白氧化态MMb相对含量与酶活等显著相关(P<0.05)。食品品质方程的动力学分析发现,大目金枪鱼的肉色稳定性与氧化性能指标随温度波动而变化显著。结论:L1与L2断链组样品在-55℃解冻流通48 h后明显下降,尤其L2组在销售(2℃)环节中为品质的劣变关键点。     

热处理延长油茶籽油氧化稳定性研究

研究了油茶籽经过不同条件加热后其压榨油氧化稳定性的变化规律,并通过测定压榨油过氧化值、酸值、水分、脂肪酸、油脂伴随物等指标探讨影响油茶籽油氧化稳定性变化的主要因素。结果表明,油茶籽经过不同温度加热20 min后,其压榨油的氧化稳定时间显著延长,30、60、90、120、150℃加热条件下分别比初始延长了1.1、4.2、5.2、3.5、3.9倍,随着加热时间的延长,60、90℃和120℃的加热温度下油茶籽油的氧化稳定性变化趋于平缓,30℃和150℃下加热40 min后氧化稳定性仍有提高,在加热60 min时,5种温度氧化稳定时间分别比初始延长了4.4、5.0、4.4、3.1、5.8倍。水分、酸值、过氧化值、角鲨烯含量、β-谷甾醇含量与油茶籽油的氧化稳定性的变化呈现负相关,说明水分、酸值、过氧化值低的油茶籽油的氧化稳定性好,角鲨烯和β-谷甾醇等抗氧化物质并不是提高油茶籽油氧化稳定性的活性成分。总酚、5-丁基二氢-2(3H)-呋喃酮、3,4-二甲基-2,5-二氢呋喃、正辛醇、苯甲醛、戊酸、辛酸、苯乙醛、壬醛等物质的含量与油茶籽油的氧化稳定性呈现正相关,说明总酚和美拉德反应产物可能是延长油茶籽油氧化稳定性的主要因素。     

PP/PET针刺过滤材料热老化性能研究

为探索聚丙烯(PP)/聚酯(PET)针刺过滤材料的耐热老化性能,采用烘箱法对试验制备的3种PP/PET针刺过滤材料样品进行不同热老化温度和热老化时间的处理,研究热老化温度和热老化时间对PP/PET针刺过滤材料各项性能的影响。结果表明:随着热老化时间的延长和热老化温度的升高,PP/PET针刺过滤材料的质量、厚度、断裂强度降低,尺寸缩小;当热老化温度超过120℃、热老化时间超过4.0 h后,热老化程度明显加剧。     

亚麻籽油调和油的热稳定性研究

为研究亚麻籽油调和油的烹饪稳定性,本实验检测调和油分别在150℃和210℃温度条件下加热不同时间后理化特性、氧化稳定性和风味成分的变化。结果表明：调和油在150℃和210℃温度条件下加热60min时间内,酸价和脂肪酸组成受影响较小,未检测到反式脂肪酸和氧化聚合物的产生,表明油脂具有较好的热稳定性;加热时间超过30min,产生了少许醛类氧化产物和不良风味物质,且过氧化值和氧化诱导时间下降,其原因可能与油脂中抗氧化成分VE被破坏有关,在150℃和210℃温度条件下加热60min后调和油中VE的含量与加热前相比分别下降了11.1%和34.3%;因此该调和油在210℃烹饪温度下加热时,时间以不超过15min为宜。     

DSC法测定水分含量对玉米淀粉糊化和老化特性的影响

建立差示扫描量热法(DSC)测定玉米淀粉糊化的方法,在升温速率和温度范围分别为10℃/min和45～95℃的条件下,研究不同水分含量对玉米淀粉糊化和老化特性的影响。结果证明玉米淀粉水分含量越高,其糊化需要的热焓越大;4℃贮存条件下,玉米淀粉老化快;水分含量越大,玉米淀粉老化速率越低。     

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.