金属离子对桑椹红色素稳定性影响

研究了几种常见金属离子Ｋ＾＋、Ｎａ＾＋、Ｚｎ＾２＋、Ｍｇ＾２＋、Ｃａ＾２＋、Ｆｅ＾３＋、Ｓｎ＾２＋、Ｃｕ＾２＋等对桑椹红色素的稳定性的影响。     

纸机改造后纸袋纸的性能及其探讨

介绍了青山纸股份有限公司１９８４年和１９９８年两次纸机改造后生产的７０ｇ／ｍ＾２、８０ｇ／ｍ＾２普通纸袋纸,８０ｇ／ｍ＾２半伸纸袋纸,８０ｇ／ｍ＾２、９０ｇ／ｍ＾２、１０５ｇ／ｍ＾２伸性纸袋纸的性能特征,,并就其生产过程进行了探讨。     

江米酒乳凝固特性研究

凝乳剂江米酒凝乳的最适温度范围为４０～４５℃;在ｐＨ值为５．５２～８．２范围内凝乳活力随ｐＨ值降低耐增大;江米酒大ｐＨ值为３．２５～４．７５范围内保证良好的稳定性（活力〉８０％;经７０℃、３０ｍｉｎ加热处理,凝乳活力损失８５％;Ｎａ＾＋、Ｋ＾＋、Ｃｕ＾２＋表现微弱的抑制作用,Ｍｇ＾２＋、Ｃａ＾２＋、Ｂａ＾２＋、Ｍｎ＾２＋、Ａｌ＾２＋、Ｆｅ＾２＋表现明显的促进作用;与皱胃酶、胃蛋白酶相比,江米酒具有     

HO.自由基在H2O2漂白中的作用

采用分光光度法，根据ＤＭＮＡ的浓度与透过率的关系，探索了ＨＯ．自由基的存在和过渡金属离子Ｈ２Ｏ２的自由基分解，发现在Ｈ２Ｏ２溶液中，随着Ｆｅ＾３＋，Ｃｒ＾３＋浓度的增加，ＨＯ．的生成量增加，Ｆｅ＾３＋与Ｍｎ＾３＋Ｃｕ＾２＋Ｃｏ＾２＋Ｎｉ＾２＋Ｎｉ＾ ２＋等离子共存时，加强了Ｆｅ＾３＋Ｈ２Ｏ２的催化分解作用。Ｈ２Ｏ２漂白过程中施加ＤＭＮＡ溶液，消除了重金属离子引起ＨＯ．漂白的不良影响，明显提高了漂浆     

碘量滴定Cu^2＋所需pH值的探讨及其Cu^2＋和Fe^3＋同时测定

探讨了ｐＨ值对碘量法测定Ｃｕ＾２＋的影响，认为只有在ｐＨ≤１的溶液中进行Ｃｕ＾２＋的碘量滴定同时测定Ｃｕ＾２＋和Ｆｅ＾２＋的方法，方法简单，快速，准确。     

蛇莓红色素稳定性的研究

蛇莓果中含有丰富的天然红色素，研究了常用食品添加剂，维生素Ｃ有机酸，糖类，和常见的几种金属离子：Ｎａ＾＋，Ｋ＾＋，Ｃａ＾２＋，Ｍｇ＾２＋，Ｆｅ＾２＋，Ｚｎ＾２＋，Ｚｌ＾３＋对蛇莓色素稳定性的影响，并对色素的耐酸碱性，耐氧化性，耐还原性，耐光耐热进行了探讨。     

磁性阳离子交换树脂对食品稀糖液中Ca^2＋,Mg^2＋脱除效能的 …

在研究了３种大孔型阳离子交换树脂脱除食品稀糖液中Ｃａ＾２＋、Ｍｇ＾２＋效能的基础上,对稀糖液中Ｃａ＾２＋、Ｍｇ＾２＋除去效果最好,交换能力最大的Ａｍｂｅｒｌｉｔｅ２５２树脂采用化学转化法进行磁化处理。比较磁化前后的阳离子交换树脂对食品稀糖液中Ｃａ＾２＋、Ｍｇ＾２＋的除去效果,结果表明,磁化过程并不影响树脂的交换容量。     

高海拔冷凉地区引种大豆栽培技术研究

７个试验结果表明，在西宁高海拔冷凉生态条件下，引种北方春大豆超早熟和极早熟品种可获成功。适宜播种其在４月底至５月初。适宜栽培宽度为４５万朱／ｈｍ＾２。播种时用４５－７５ｋｇ／ｈｍ＾尿素和４５０ｋｇ／ｈｍ＾２过磷酸钙做种肥，始花后分２－３次追施１０５－１５０ｋｇ／ｈｍ＾２尿素，开花期至鼓粒期进行２－３次灌水，可获１５００ｋｇ／ｈｍ＾２以上量，最高产量达２２８３ｋｇ／ｈｍ＾２。     

硫酸镁转化法制取硫酸钾的最佳工艺条件的探讨

本文得用Ｋ＾＋，Ｍｇ＾２＋∥Ｃｌ＾－，ＳＯ＾２－４－Ｈ２Ｏ２５℃体系相图，对硫酸镁两段转化法制取硫酸钾的工艺过程进行了分析和计算，并对最佳工艺条件进行了探讨。     

SO2—O2—H2O表面催化反应“干”机理的研究

ＳＯ２－Ｏ２－Ｈ２Ｏ表面催化反应机制的研究是环境科学中的一个重要课题。用格子模型研究了该反应的“干”要理。利用“部分模拟法”得到了三种情况下反应价格绵动力学相图：１）无表面吸附物种的脱附；２）吸附态分子Ｏ２＾＊或Ｈ２Ｏ＾＊有一种可脱附；３）Ｏ２＾＊和Ｈ２Ｏ＾＊都可脱附。．     

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.     

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.