水硬度传感器的研制

以P.V.C为载体,磷酸酯类的钙盐为电活性物质研制而成水质硬度传感器,详细介绍了水硬度传感器的电极膜片及电极制作过程,并对所研制的传感器进行了灵敏度等性能测试。结果表明所研制的水质硬度传感器具有较高的灵敏度,是一种较为方便的水质硬度快速检测仪器设备。     

基于光纤传感器的饮用水水质色度自动检测方法分析

正随着我国社会不断发展,关于饮用水水质检测方法也获得了改进。水质监测是水资源保护中必不可少的一部分,每种颜色都会对水体外观,如颜色和透明度造成很大影响和改变。因此,在水质控制方面可以先从水的色度入手。基于此,对光纤传感器在饮用水水质色度检测进行分析和讨论。目前光纤传感器在饮用水水质色度检测方面主要有两种方法。应用光纤传感器检测和过去传统检测方法有着很大区别。传统方法主要是通过眼睛对比水质,并将水按不同比例倍数     

一种褐色益生菌乳饮料的研制

以脱脂牛奶与果葡糖浆为原料,经热处理发生美拉德反应,再通过干酪乳杆菌长时间发酵,与白砂糖、果胶、水混合制得一种养乐多风味的褐色益生菌乳饮料.通过对果胶用量、水质硬度以及热处理时间的优化,开发出一种风味浓郁、稳定性优的褐色益生菌乳饮料,优化参数为:果胶添加量2.5‰、热处理时间90min、水质硬度0.     

基于声振频带幅值特性香梨硬度无损检测研究

本文采用压电梁式传感器对香梨进行激励感测,分析了该装置采集的响应信号的稳定性,研究了频带幅值参数与香梨硬度的相关性,并采用频带幅值参数对其硬度进行主成分回归(PCR)分析,建立香梨硬度的检测模型。研究结果表明:香梨声振检测装置的时域和频域信号稳定,在320~880 Hz波段可提取8个频带幅值参数,它们与M-T检测硬度的相关系数最高仅为0.63,采用这些频带幅值PCR法构建的香梨硬度检测模型的校正集和验证集相关系数r_c与r_v分别为0.77和0.66,均方根误差RMSEC和RMSEV分别为1.23和1.59,对香梨硬度的检测敏感度仅为51.56%,模型检测性能较低、稳定性较差;引入香梨质量对模型修正,r_c和r_v分别升高到0.81和0.72,RMSEC和RMSEV分别降低为1.13和1.44,模型的检测性能和稳定性得到明显提高,对香梨硬度变化的敏感度提高至58.28%,与M-T检测法敏感度的差异仅为6.21%,可以适用于香梨硬度的无损检测。     

水质软化对印刷工艺的改善

润版液的水质对润湿系统十分重要,水质过硬会影响润湿系统的正常工作,而对印刷工艺过程和印刷质量产生影响.本公司于2003年7月安装了一台典冠逆渗透R 0膜纯水机,将润湿系统水的硬度从1 8度降到了2度,而水质硬度的变化,对实际印刷工艺产生了如下影响.     

水源水和管网末梢水水质检测分析

目的:分析水源水和管网末梢水的水质检测情况。方法:在2019年1—12月,以东营市某地区的水源水和管网末梢水为研究对象,参照GB/T 5750-2006《生活饮用水标准检验方法》进行水样采集、储存、运送及水质卫生检测,根据GB 5749-2006《生活饮用水卫生标准》评价水质合格状况,并分析15项常见指标的检测结果。结果:水源水和管网末梢水各采集12份样本,水源水水质卫生检测合格9份,合格率为75.0%;管网末梢水水质卫生检测合格10份,合格率为83.3%;总体合格率为79.2%。15项指标的检测结果显示,水源水、管网末梢水pH值、总硬度、硝酸盐、菌落总数、总大肠菌群、锰、铁、铜、锌与砷的检测结果均合格,水源水中色度、浑浊度、耗氧量、硒与铅的合格率依次为91.7%、91.7%、83.3%、91.7%与83.3%,管网末梢水中色度、浑浊度的检测结果均合格,耗氧量、硒、铅依次为的合格率依次为91.7%、91.7%、83.3%。结论:本市某地区水源水和管网末梢水水质卫生有待提升,水源水的水质卫生相对较差,应加强水质卫生管理,提高水质质量,以确保居民用水安全。     

水中硬度测定的影响因素及其对策

在长期的水质监测分析工作中，针对水中硬度指标的测定，总结出了影响测定准确度的主要因素，提出了相应的解决措施，以期确保水中硬度指标测定的准确度。     

漂染中水回用的探讨

介绍了印染生产对水质的要求,污水深度处理中水回用技术以及中水连续回用中的反渗透除盐技术.以福建凤竹公司污水处理系统为例,检测了经污水技术处理后的各项水质数据.结果表明,采用水解-接触氧化-气浮处理工艺,处理水质大大优于国家规定的一级排放标准,但与中水回用所要求的色度、硬度、电导率等指标还有距离;在原有设施的基础上改进,增加无阀滤池工序,对漂染中水进行深度处理,除了电导率仍与处理前相差不大外,其余指标均符合中水回用漂染生产要求;再加上反渗透除盐处理后,电导率低到38μs/cm2,其他指标更相当于或优于自来水水质,可以实现大规模回用.     

常规水质检测技术应用中的注意事项探究

为稳步提升水质检测成效,排除干扰因素对于水质检测工作的影响,构建起更为高效、更为科学的水资源管理体系,在健全管理制度的基础上,有必要发挥技术优势,通过水质检测技术资源的有效整合,突出检测成效,优化检测流程,实现对水质的全程化管控.本文着眼于实际生活中常规水质检测的相关要求,依托各类检测技术手段,搭建起体系化的水质检测技...     

生物传感器技术在大肠杆菌内毒素检测中的应用进展

内毒素是一种热源型毒素，对人体和动物健康产生严重危害。合成生物食品和发酵食品因易受微生物污染，从而导致内毒素污染愈发严重，目前传统检测方法为鲎试验法为主，但是存在检测时间长、效率低等问题，而生物传感器具有灵敏度高、检测速度快、成本低等优点，在内毒素检测领域被普遍应用。因食品中内毒素检测需求不断增大，对生物传感器的要求也在不断提高，通过适配体、肽、金纳米材料，碳纳米材料等制备成的生物传感器，其灵敏度、稳定性等得到极大提高。随着材料技术的不断进步，未来的生物传感器会逐渐向小型化，经济化，便携化发展。本文主要综述了生物传感器在内毒素检测领域的应用，为基于生物传感器检测大肠杆菌内毒素的研究提供一定的参考价值。     

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

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.     

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.     

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.     

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.     

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.     

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.