黑糯玉米芯色素的提取及性质研究

研究了黑糯玉米的穗芯色素的提取工艺，并研究了酸度，温度、光照、碳水化合物、微波、氧化剂、还原剂、金属离子对色素稳定性的影响及黑糯玉米芯色素的部分理化性质。结果表明：该色素采用0．05mol／HCl溶液以样品与浸提剂比=1：20浸提24h，在60℃下二次浸提后，减压浓缩温度为60℃、真空度为0．9Mpa，最后减压干燥(温度为60℃、真空度为0．9Mpa)得该色素的平均得率为7．03％；该色素的特征吸收峰为510nm，色素类型为花色苷类；在酸性条件下较稳定，在碱性条件下易褪色；热、光、碳水化合物、微波对色素稳定性无影响，可溶性淀粉有增色作用；色素对H2O2，Na2SO3较敏感；几种常见的金属离子(除Fe^(3 ))对色素色泽无影响。     

R362菌株产黑色素提取及稳定性研究

通过液体培养R362菌株,提取其产生的黑色素,并研究酸度、温度、光照、碳水化合物、氧化剂、还原剂、金属离子对色素稳定性的影响。结果表明:该色素的最大吸收峰为390nm,在碱性条件下较稳定,在酸性条件下易褪色;热、光、碳水化合物对色素稳定性无影响,色素对H2O2和Na2SO3较敏感;几种常见的金属离子(除Fe3 )对色素色泽无影响。     

托柄菝葜果色素提取及其性质研究

以民族药托柄菝葜的成熟果实为材料,对其红色素的提取条件及理化性质进行研究.结果表明,托柄菝葜果色素提取的最佳条件为:40％vol乙醇水溶液、浸提温度60℃、浸提时间lh.托柄菝葜果色素在自然光照下稳定,但添加金属离子的色素溶液对光不稳定;色素溶液在酸性环境中呈现鲜艳的橙红色,在中性及碱性环境中变为褐绿色.VC对托柄菝葜色素具有增色作用;柠檬酸、EDTA对色素无明显影响;亚硫酸钠、高锰酸钾及苯甲酸钠对色素具有减色作用.金属离子Ca2+、Mn2+、Zn2+、K+、Na+、Fe2+、Mg2+、Cu2+、Co2+、Al3+、Pb2+等离子能减弱托柄菝葜果色素对光的稳定性;Sn2+、Fe3+影响色素稳定性.     

西红花色素的提取及稳定性研究

利用有机溶剂提取西红花色素,并考察了食品添加剂、金属离子、碳水化合物、pH值、光照及温度等对其稳定性的影响。结果表明:西红花色素溶液在强光、碱性环境和高温下不稳定,在酸性、中性环境、葡萄糖溶液、蔗糖溶液、大部分金属离子和食品添加剂溶液中表现稳定,但溶液中的Fe~(3+)对该色素有较大影响,淀粉溶液对西红花色素具有增色作用。     

橘皮色素加盐-微波法提取新工艺的优化及稳定性研究

用加盐-微波法提取橘皮色素,通过正交实验优化提取工艺条件。结果表明,橘皮色素在330.0 nm处吸光度有最大值。最佳提取工艺为:微波时间90 s,料液比1:15,加盐量(盐/橘皮质量比)4%,水浴温度50℃,水浴浸提2 h。同时,橘皮色素溶液稳定性研究表明,金属离子Al~(3+),Co~(2+),Cu~(2+),Fe~(3+)对橘皮色素稳定性有一定影响,其中Fe~(3+) 影响最大;食品添加剂中,仅碳酸氢钠会降低橘皮色素稳定性;碱性条件下,橘皮色素稳定性明显下降;该橘皮色素对还原剂稳定,强氧化剂KMn O_4对其稳定性影响较大;橘皮色素对光比较稳定。     

日本小糪叶子红色素的提取及稳定性研究

以日本小檗的叶子为材料提取红色素,考察pH、金属离子、氧化剂、还原荆、碳水化合物、微波加热、光、温度等物理化学因素对该色素稳定性的影响.结果表明,该色素在酸性条件下较稳定;碳水化合物在一定的范围内对色素的稳定性、呈色有保持作用;色素对K+、Mg2+、Ca2+、Na+ 比较稳定,对Al3+ 不稳定;氧化剂、还原剂对色素稳定性均有影响,其中还原剂的影响较大;色素对光、热有较好的稳定性.该色素在化妆品、染料、食品、饮料等工业领域具有较大的应用前景.     

黑花生衣色素的应用性质研究

通过黑花生衣色素在不同光照、温度、糖、盐、防腐剂、抗坏血酸、pH值、氧化剂、还原剂、金属离子等环境条件下的结构和色泽变化,探讨其对食品加工理化因子的稳定性。结果表明:黑花生衣色素对光不稳定,对热稳定,耐糖、耐盐性好,耐防腐剂。抗坏血酸可导致色泽加深。该色素适应pH范围较广,通过调节pH值可获得不同颜色。该色素耐还原性,但对氧化剂比较敏感,色素对数种金属离子的稳定性较好,Cu2+和Fe2+2种金属离子对色素稳定性影响比较大,使色素产生沉淀。黑花生衣色素性质比较稳定,色调自然,应用性状良好,使用时注意避光保存,避免氧化剂及Cu2+和Fe2+2种金属离子的混入。     

紫红豇豆色素理化性质及稳定性研究

以紫红豇豆为原料,研究了豆荚与种子中紫红色素理化性质以及防腐剂、pH值、光照、温度、还原剂、氧化剂和7种常见金属离子对其稳定性的影响,旨在为紫红豇豆色素的提取加工及工业应用提供理论依据。结果显示：豆荚与种子的紫红色素在紫外区的最大吸收波长分别为270nm和207nm,在可见区的最大吸收波长分别为542nm和481nm,紫红色素水溶性好,颜色随pH值变化而变化（pH＜3时颜色鲜红;pH＞7时,颜色由紫色转为绿色）。酸性条件（pH＜）下该色素对光、低温有很好的稳定性,耐氧化性与耐还原性较强。Ca2＋、Na＋、Mg2＋、K＋、Zn2＋等离子对紫红色素的稳定性影响不大,Cu2＋、Fe3＋离子使色素稳定性变差。     

紫色马铃薯花色苷理化性质研究

采用溶剂浸提法提取紫色马铃薯花色苷,研究pH 值、温度、光照对色素的影响,探讨在金属离子、氧化还原剂、防腐剂、食盐、葡萄糖等存在的条件下花色苷的稳定性。结果表明：紫色马铃薯花色苷在可见光范围内的最大吸收波长为536nm,为水溶性色素;70℃以内比较稳定;pH 值对色素有显著影响,在酸性条件下较为稳定;金属离子Al3+、Zn2+、Na+、Ca2+ 对色素色泽无不良影响,而Sn2+、Fe3+ 影响显著;色素耐氧化性、耐还原性差,且光照能加速色素降解;防腐剂、食盐及葡萄糖等常用添加剂对色素无影响。     

枣红素的提取及稳定性研究

对从残次枣中提取红色素及其稳定性进行了研究,结果表明:枣红素的最大吸收波长在656 nm处,最佳提取条件是最佳提取条件是在0.01 mol/L的NaOH,70℃,超声波提取1.5 h;对大枣红色素的稳定性分析中发现,该色素对光和热稳定;pH对大枣红色素的稳定性影响明显,在pH11附近色素的稳定性较好;金属离子K+、Na+、Fe3+、Mg2+对该色素的稳定性较好。     

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.