响应面法优化紫茄子皮原花青素提取工艺研究

原花青素能够阻止自由基的生成并能清除自由基,紫茄子皮中原花青含量丰富,提取其中的原花青素具有重要经济价值。考察浸提时间、乙醇浓度、料液比对原花青素提取率的影响,采用中心组合对提取工艺的料液比、浸提时间和乙醇浓度三因子进行响应面设计,得出原花青素最佳提取条件为料液比1∶15(g/m L)、浸提时间4 h、乙醇浓度80%时,提取率最高为10.46%。     

正交试验法优化苹果皮中原花青素的提取工艺研究

对苹果皮中原花青素的提取工艺条件进行了优化,在单因素的基础上,采用L9( 34)正交试验设计,研究乙醇浓度、料液比、提取时间和提取温度对苹果皮中原花青素得率的影响.结果表明,对苹果皮原花青素得率的影响顺序是:乙醇浓度＞料液比＞提取时间＞提取温度,有机溶剂提取苹果皮原花青素的最佳工艺条件是:乙醇浓度60％,料液比1∶10 (g/mL),提取温度65℃,提取时间120min,原花青素得率达到2.82mg/g于皮.     

葡萄籽原花青素的微波萃取工艺优化

以原花青素提取量为指标,考察微波处理时间、提取温度、乙醇体积分数、料液比等因素对葡萄籽原花青素提取的影响并利用正交优化试验设计确定微波萃取原花青素的最优工艺。结果表明:各因素对原花青素提取量的影响大小依次为微波温度微波时间乙醇体积分数料液比。微波提取原花青素最优工艺条件为微波处理时间20 min、微波提取温度80℃、乙醇体积分数50%、料液比1∶6(g/mL)。在此条件下,原花青素提取量均值为51.77 mg/g,相对标准偏差为1.45%。与传统浸提法相比,微波萃取原花青素耗时短、提取效率高,且对原花青素的破坏性小。     

超声提取葡萄籽原花青素工艺的优化及其抗氧化活性研究

研究利用响应曲面法优化超声提取葡萄籽原花青素的工艺。在单因素实验基础上,采用中心组合设计响应面实验,考察了提取温度、液料比、乙醇浓度以及超声时间对原花青素提取率的影响,并建立回归模型。优化后的工艺:提取温度55℃,液料比20(mL/g),乙醇浓度65%,超声时间10min;在此条件下葡萄籽原花青素的提取率为2.482%,与回归模型预测值的相对偏差为0.36%。同时进行了提取物的抗氧化性检验,结果表明葡萄籽原花青素对超氧阴离子自由基具有较好的清除能力,且呈剂量相关性。     

红玉米原花青素提取纯化与抗氧化性的研究及应用

红玉米富含原花青素,抗氧化能力较强。采用乙醇有机溶剂提取法对红玉米中原花青素的提取,考察提取温度、液料比和乙醇浓度等因素对原花青素提取率的影响。通过响应面试验获得红玉米提取原花青素的最佳条件：提取时间2.86 h、液料比19.70:1 mL/g、提取温度55.67℃。红玉米原花青素最高提取率为1.92 mg/g。通过原花青素的总抗氧化性能力测定得出,原花青素浓度在0～0.0292mg/mL范围内,随着红玉米原花青素的浓度增大,其总抗氧化能力也相应增大;当原花青素浓度达到0.0921 mg/mL时,其总抗氧化能力达到1.555μmol/mL。     

野葛花黄酮和花青素的提取及抗氧化性研究

为更好开发利用野葛,研究野葛花黄酮和花青素的超声辅助乙醇浸提工艺,以及黄酮和花青素提取物的抗氧化性。结果表明:野葛花黄酮的最佳工艺条件为料液比为1∶30(g/mL)、提取温度为40℃、提取时间为110 min,葛花黄酮得率为2.84%;野葛花花青素的最佳提取工艺条件为乙醇浓度60%,料液比1∶30(g/mL),提取时间120 min,提取温度60℃,花青素得率为2.17%;野葛花黄酮和花青素对羟自由基的清除效果明显优于抗坏血酸。试验结果可为综合开发利用葛根资源,延长葛根加工的产业链提供一定参考依据。     

超声波辅助提取山竹果皮中的原花青素

文中研究了山竹果皮中原花青素的超声辅助提取工艺条件。通过单因素试验分析超声提取过程中超声功率、料液比、乙醇浓度、提取时间和温度等因素对原花青素提取率的影响,在此基础上,采用L9(34)正交试验优选出山竹果皮中原花青素提取的最佳条件。结果表明:各因素对原花青素提取率的影响大小顺序为乙醇浓度(B)>温度(C)>料液比(A)>时间(D);最佳工艺条件为料液比为1∶30,乙醇体积分数60%,提取温度50℃,提取时间45 min,此条件下山竹果皮中原花青素的提取率为15.61%。     

蚕豆皮原花青素提取工艺优化

以蚕豆皮为材料,探讨微波预处理-乙醇提取法提取原花青素的工艺条件。分别考察预处理工艺中微波功率、微波时间、加水量,提取过程中的料液比、提取温度、提取时间对原花青素提取率的影响。结果表明：微波预处理-乙醇提取最佳工艺为微波功率140W、微波处理时间50s、加水量2mL/g、液料比21:1(mL/g)、温度55℃、70%乙醇溶液提取72min,原花青素提取率为94.53%。     

响应面法优化女贞子原花青素提取工艺及抗氧化研究

Box-Behnken响应面法优化超声辅助提取女贞子原花青素工艺。以原花青素的提取率为考察指标,提取时间、超声功率、液料比和乙醇体积分数为考察因素,采用四因素三水平做响应面分析。利用邻苯三酚法、DPPH和水杨酸法对女贞子原花青素抗氧化性进行研究。结果表明,女贞子中的原花青素的最佳提取工艺为:提取时间33 min,超声功率400 W,液料比27∶1(mL/g),乙醇浓度50%。在最佳提取条件下,原花青素的提取率为(2.85±0.06)%。当原花青素浓度为1.0 mg/m L时,对DPPH自由基的清除率可达到97%;对超氧阴离子的清除率可达到60.14%;对羟自由基的清除率可达到78.88%。该研究优化的女贞子原花青素提取工艺合理、稳定,技术可行,提取的原花青素有较好的抗氧化性。     

凤冈绿茶中原花青素的提取工艺优化

对凤冈绿茶中原花青素的提取工艺条件进行优化。本文在单因素试验基础上,采用响应面法研究原花青素提取工艺中乙醇浓度、超声温度、超声时间和料液比四个因素对凤冈绿茶中原花青素得率的影响。结果表明,最佳提取工艺参数为:乙醇浓度83%、超声温度58 ℃、超声时间40 min、料液比1:33 g/mL。在此条件下,凤冈绿茶中原花青素得率为4.798%±0.05%,与模型预测值(4.804%)接近,且其相对误差为1.05%,说明该模型回归项良好,拟合度较好,优化后的工艺条件可行,可以为凤冈绿茶中原花青素的进一步开发利用提供理论依据。     

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.     

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.     

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.     

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.