响应面法优化超声辅助提取软枣猕猴桃叶多酚工艺

以软枣猕猴桃叶为原料,采用福林-酚比色法对软枣猕猴桃叶多酚进行测定并对提取工艺进行优化研究。利用乙醇超声波提取法对软枣猕猴桃叶多酚进行辅助提取,通过响应面试验,优化得到软枣猕猴桃叶中多酚最优提取工艺:料液比1∶22(g/mL)、乙醇体积分数45%、超声时间为10 min,在此条件下,软枣猕猴桃叶多酚提取量为54.67μg/g,为软枣猕猴桃叶深入开发利用提供理论依据。     

响应曲面法优化软枣猕猴桃多糖超声辅助提取及乙醇沉淀工艺

分别对软枣猕猴桃多糖超声辅助提取工艺及乙醇沉淀工艺进行优化。以软枣猕猴桃多糖提取率为响应值,以超声功率、超声时间、液料比为自变量,利用响应面分析法,确定超声辅助提取软枣猕猴桃多糖的最佳工艺条件;以软枣猕猴桃多糖提取率为响应值,以乙醇体积分数、乙醇用量、醇沉时间为自变量,确定乙醇沉淀软枣猕猴桃多糖的最佳工艺条件。结果表明：超声辅助提取软枣猕猴桃多糖的最佳工艺条件为超声功率260W、超声时间8min、液料比6:1(mL/g),在此条件下,软枣猕猴桃多糖提取率达到1.48%(m/m);乙醇沉淀软枣猕猴桃多糖的最佳工艺条件为乙醇溶液体积分数90%、乙醇用量为浓缩液的7倍、醇沉时间4h,在此条件下,软枣猕猴桃多糖提取率达到1.55%(m/m)。     

基于响应面设计的骆驼蓬总生物碱提取工艺的研究

以骆驼蓬为研究对象,选择乙醇体积分数、液料比(mL∶g)、回流时间、超声时间4个影响因素,进行响应面试验设计,建立骆驼蓬总生物碱的提取工艺;用高效液相色谱法测定最佳工艺下提取的骆驼蓬总生物碱的含量。结果表明,其最佳提取工艺条件是乙醇体积分数40.0%、液料比15.0(mL∶g)、回流时间2.3h、超声时间10.5min,此工艺条件下骆驼蓬总生物碱含量为11.34%。     

微波辅助法提取野生软枣猕猴桃茎黄酮的工艺优化

研究了微波辅助法提取野生软枣猕猴桃茎黄酮类化合物的工艺条件。通过单因素实验分别考察微波功率、提取时间、乙醇浓度、料液比对黄酮提取率的影响,以软枣猕猴桃茎黄酮的提取率为指标,根据单因素实验结果设计正交实验,得出微波辅助法提取的最佳工艺条件：微波功率为300W,乙醇浓度为70%,料液比为1∶32,提取时间为5min,此条件下软枣猕猴桃茎黄酮提取率为1.80%。     

新疆红果桑果实总生物碱的提取工艺的研究

采用分光光度法,以盐酸小檗碱为标准品测定新疆红果桑中的总生物碱含量。在提取过程中通过单因素试验分析乙醇体积分数、料液比、提取时间及提取温度4 个主要因素对提取率的影响。在单因素试验的基础上通过正交设计法进行试验,优化红果桑总生物碱提取工艺条件。结果表明：红果桑总生物碱的最佳提取工艺条件为乙醇体积分数90%、料液比1:15、提取温度70℃、提取时间6h。根据最佳提取工艺条件测得的红果桑的总生物碱提取率为2.5%。该实验结果可靠,方法简便,最佳条件适合批量生产中该药材的提取。     

软枣猕猴桃黄酮超声辅助提取条件优化

目的：研究软枣猕猴桃黄酮的最佳提取条件。方法：以乙醇为溶剂,采用超声波辅助提取法对软枣猕猴桃中的黄酮进行提取,并通过响应面Box-Behnken设计分析方法对其最佳提取条件进行优化。结果：软枣猕猴桃总黄酮最佳提取条件为乙醇体积分数70%、超声时间6min、超声功率270W,在此条件下,实际提取率为0.0297%,与预测值基本吻合。结论：超声波辅助提取法适合于软枣猕猴桃黄酮的提取。     

正交实验法优化枣核黄酮的超声提取工艺研究

采用正交实验法优选枣核中总黄酮的最佳超声提取工艺。以芦丁为对照品,采用分光光度法进行测定,以枣核中黄酮含量作为考查指标,通过单因素实验研究超声波功率、提取时间、提取温度、料液比和提取溶剂乙醇体积分数对提取效果的影响,再利用正交实验法优化最佳提取工艺条件。结果表明,对枣核黄酮提取影响的大小次序为提取温度>料液比>提取时间>乙醇体积分数>超声波功率,最佳提取工艺为:提取温度55℃,料液比为1:50,提取时间为40min,乙醇体积分数为50%,超声波功率为400W,在该条件下枣核黄酮粗品的提取率为12.45%,粗品中黄酮含量为6.83mg.g-1,能显著提高枣核黄酮的提取效率。     

金鸡毛草叶和茎总黄酮的超声波提取工艺优化

采用超声波法分别优选金鸡毛草的叶和茎中总黄酮的提取工艺。在单因素的基础上以不同的提取溶剂、提取溶剂体积比、超声波提取时间、料液比为考察因素,分别以金鸡毛草的叶和茎总黄酮得率为指标,采用正交试验优选最佳提取工艺。叶的最佳提取工艺是以乙醇为最佳提取溶剂,乙醇体积分数为65%,料液比为1∶50(g/m L),超声时间为25 min,在此条件下叶的总黄酮得率为19.24 mg/g,提取率为52.35%;茎的最佳提取工艺是以乙醇为最佳提取溶剂,乙醇体积分数为45%,料液比为1∶50(g/m L),超声时间为35 min,在此条件下茎的总黄酮得率为3.12 mg/g,提取率为43.40%,表明总黄酮成分主要存在于金鸡毛草的叶的部位。     

软枣猕猴桃根蒽醌类成分超声提取及其体外抗氧化活性研究

以东北地区软枣猕猴桃根为原料,以蒽醌提取率为指标,通过单因素和响应面实验对软枣猕猴桃蒽醌类化合物提取工艺中乙醇浓度、料液比、提取时间、提取温度等影响因素和提取液的抗氧化活性进行探讨。采用化学模拟体系分析了其对DPPH自由基的清除能力、对Fe3+离子的还原能力以及与Fe2+的螯合能力并与VC进行比较。结果表明超声波法提取软枣猕猴桃根蒽醌的最佳工艺:超声波率200W,乙醇浓度80%,料液比1∶25,温度70℃,提取时间15min,在此条件下软枣猕猴桃根中蒽醌类成分的提取率为1.40%;软枣猕猴桃根蒽醌类成分具有较强的清除DPPH自由基能力、还原力和螯合能力,并与质量浓度呈一定正相关关系。     

超声波提取苦菜叶、根中总多酚的工艺研究

以苦菜叶、根为原料,采用超声波辅助乙醇提取总多酚,福林-酚比色法在765 nm波长处测定总多酚的含量。通过单因素试验,正交试验确定最佳提取工艺。单因素试验表明:在提取温度为50℃、提取时间为1.5 h、料液比为1∶15(g/mL)、乙醇体积分数为50%时,苦菜叶、根中总多酚得率都达到最高。提取苦菜叶中总多酚的最佳条件为:提取温度为50℃、提取时间为2.0 h、料液比为1∶20(g/mL)、乙醇浓度为50%。提取苦菜根中总多酚的最佳条件为:超声波功率400 W、提取温度为40℃、提取时间为1.5 h、料液比为1∶15(g/mL)、乙醇体积分数为50%。     

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.