微波辅助提取金银花中绿原酸及其清除自由基活性初步研究

目的筛选微波辅助提取金银花中绿原酸的最佳工艺;初步探讨绿原酸清除自由基的活性。方法以金银花中绿原酸含量为考察指标,考查提取溶剂浓度、料液比、提取时间、微波功率等因素对提取效果的影响。采用正交试验设计优化了最佳提取工艺,采用DPPH法测定不同物质对总自由基的清除作用。结果最佳提取条件为:乙醇浓度55%,料液比1:40,提取时间2min,微波功率520W。金银花中绿原酸有良好的抗氧化性。结论微波辅助提取金银花中绿原酸的最佳工艺可为其开发应用提供参考。     

响应面法优化微波超声双辅助提取金银花绿原酸工艺

以金银花为原料,采用微波超声双辅助提取绿原酸。通过单因素实验对乙醇浓度、超声温度、超声时间、料液比、微波功率、微波时间等工艺参数进行研究,并通过响应面法优化提取工艺,建立二次多项数学模型。结果表明,单因素和响应面优化金银花绿原酸的最优工艺参数为:微波功率400W、微波时间94s、液料比42∶1mL/g、乙醇浓度70%、超声温度为60℃、超声时间60min,此条件下金银花绿原酸提取率为5.45%。     

正交试验法优化卷心菜叶中绿原酸提取工艺研究

以卷心菜叶为原料,研究采用微波法辅助提取卷心菜叶中绿原酸的提取工艺。实验中以绿原酸的提取率为指标,以乙醇为提取剂,考察乙醇体积分数、料液比、微波温度、微波时间、微波强度等因素对卷心菜叶中绿原酸提取率的影响。通过L16(45)正交优化绿原酸提取工艺,结果显示,最佳工艺条件为:微波温度60℃、微波时间6 min、微波功率300 W、乙醇体积分数60%、料液比1∶20。在此最佳工艺条件下,卷心菜叶中绿原酸的提取率为1.2682%。     

微波提取灵芝中三萜类化合物的研究

利用微波技术研究灵芝三萜类化合物的提取工艺条件.以乙醇浓度、提取时间、功率、液料比、温度为工艺参数,通过单因素及Box-Benhnken模型,做四因素三水平响应面优化提取条件试验;通过响应面模型的回归分析,获得最佳提取工艺条件:乙醇体积分数75%、提取温度75℃、功率870W、液料比33 mL/g、时间17 min.在此条件下灵芝三萜的平均提取率为1.043%,一次提取率可达93%.与未经微波处理的超声法、回流法、浸提法相比,微波处理可使三萜提取率提高150%.超声法、回流法和浸提法的三萜提取率分别为微波提取法的72%、86%和63%,且提取时间长,溶剂耗量大.采用微波技术提取灵芝三萜类的工艺,稳定性好,提取率高.     

甘薯叶中绿原酸最佳提取工艺的研究

目的:优选甘薯叶中绿原酸提取的工艺条件。方法:用正交设计对传统水煎法、乙醇回流法、超声波法等提取工艺进行比较,以提取物中绿原酸的含量与提取率为评判指标,考察浓度、时间、料液比等因素对有效成分绿原酸提取率的影响。采用紫外分光光度法测定该成分的含量。结果:最佳提取工艺为乙醇回流法,最佳提取条件为:60%乙醇,料液比1:20,回流提取1.5h。此条件下绿原酸含量与提取率最高。影响提取的主次因素为:乙醇浓度>回流时间>料液比。     

微波辅助PEG提取金银花叶中绿原酸的工艺优化

为了优化微波辅助聚二乙醇（PEG）提取金银花叶中绿原酸的工艺,通过单因素试验筛选提取温度、PEG-200体积分数、提取时间等关键影响因素,以绿原酸提取率为响应值设计响应面优化试验。结果表明：微波辅助PEG提取金银花叶中绿原酸的最佳工艺为微波功率350 W,微波时间70 s,料液比1∶20（g∶mL）,提取温度82 ℃,PEG-200体积分数40%,提取时间24 min,该条件下绿原酸提取率为5.87%。该工艺简单可行、快速有效、绿色环保,可用于提取金银花叶中绿原酸工业化生产。     

微波辅助提取香椿叶黄酮工艺的研究

比较微波辅助甲醇提取香椿黄酮与乙醇提取、甲醇回流和乙醇回流等工艺提取香椿黄酮的效果,用正交设计筛选微波辅助乙醇提取工艺条件,并探讨材料的液料比、体积分数、微波处理时间、微波功率对提取效果的影响,结果表明:微波辅助甲醇提取和乙醇提取效果明显优于其它传统方法;最佳工艺条件:液料比25 mL/g,乙醇体积分数70%,微波功率400 W,处理15 min。此工艺提取率达到70.15%,是一种高效、节能的提取香椿黄酮的工艺。     

微波干法辅助提取绞股蓝总皂苷的研究

以绞股蓝为原料,研究微波干法辅助提取绞股蓝总皂苷的新工艺.通过正交试验,得出微波处理最佳工艺参数为:功率800 w、100%微波、辐射时间2 min.在此条件下,经微波预处理70%乙醇快速浸泡提取,所得的绞股蓝总皂苷提取率为8.37%.与传统的乙醇回流提取法进行比较,发现微波干法辅助提取绞股蓝总皂苷提取时间缩短了近9 h,提取率提高了15.8%.     

酶法辅助聚二乙醇-200提取金银花叶中绿原酸的工艺优化

为了优化酶法辅助聚二乙醇（PEG）-200提取金银花叶中绿原酸的工艺,利用单因素试验确定PEG-200体积分数、料液比、酶解时间等关键影响因素,以绿原酸提取率为响应值进行响应面优化分析。结果表明,金银花叶中绿原酸用纤维素酶辅助PEG-200提取的最佳条件为纤维素酶添加量为2%,料液比1∶27（g∶mL）,PEG-200体积分数50%,pH 4,55 ℃酶解2.0 h,提取温度90 ℃,提取时间15 min,在该条件下,绿原酸提取率为6.59%。该工艺环境友好、条件温和、提取效率高,可用于工业化提取金银花叶中绿原酸。     

金银花中绿原酸的超声波提取工艺优化

研究从金银花中提取绿原酸的工艺。通过研究乙醇浓度、温度、料液比、超声时间、超声功率等因素对提取效率的影响。在运用超声波法下得出绿原酸提取工艺的最佳工艺参数:乙醇浓度为70%,浸提温度为55℃,料液比为1∶20(g/m L),超声时间为1.5 h,超声功率为700 W。在此条件下采用紫外分光光度法(UV)对绿原酸产品进行检测,在328 nm波长下,得到绿原酸的最大峰值,计算得率为7.887%。     

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.