响应面法优化超声辅助浸提葡萄籽原花青素

利用响应面优化法研究葡萄籽原花青素的超声辅助浸提工艺,以原花青素提取率为指标,在考察提取时间、提取温度、乙醇浓度、液料比对提取率影响的基础上,采用Box-Behnken中心组合法设计响应面优化试验方案,利用最小二乘回归分析建立预测模型,优化超声辅助浸提工艺参数。结果表明：各因素对葡萄籽原花青素提取率的影响大小依次为提取时间＞提取温度＞液料比＞乙醇浓度。响应面优化最佳工艺为室温（20℃）下超声处理20 min,水浴热回流提取时间1.0 h,提取温度70℃,乙醇浓度60%,液料比15∶1（mL/g）。在此条件下葡萄籽中原花青素提取率为4.68%,与模型预测值4.71%接近,相对标准偏差为1.22%,响应面法优化葡萄籽原花青素的提取工艺有良好的重现性,可为葡萄籽原花青素提取工业化提供参考。     

酶促法提取油菜籽皮中的原花青素研究

研究采用纤维素酶、半纤维素酶和果胶酶共同酶解油菜籽皮干粉提取原花青素。以原花青素提取质量比为指标,通过单因素试验,确定原花青素的最优提取工艺。结果表明酶促反应的最佳反应体系:纤维素酶、半纤维素酶和果胶酶配比30∶7∶6,复合酶用量40U/g,酶解pH 5.0、酶解温度55℃、酶解时间120min。验证实验表明酶促法油菜籽皮原花青素的提取质量比为3.59mg/g,比普通溶剂法提取质量比提高了66.98%。采用酶促法可以较高程度地提高油菜籽皮原花青素的提取质量比。     

慕萨莱思酒中原花青素提取与纯化条件的优化

以慕萨莱思酒为原料,采用乙醇浸提法提取原花青素,利用单因素试验对料液比、乙醇体积分数、浸提温度、浸提时间等工艺条件进行分析与优化,采用大孔树脂对提取的原花青素进行纯化。结果表明,乙醇浸提工艺参数对慕萨莱思酒原花青素提取有显著影响,影响显著顺序为:提取时间提取温度乙醇体积分数料液比。最佳工艺条件为提取时间55 min,提取温度50℃,料液比1︰8.5(g/m L),乙醇体积分数70%;原花青素的最佳纯化条件是AB-8大孔树脂纯化,进样质量浓度6 mg/m L,最佳流速4 BV/h,最佳乙醇洗脱体积分数为50%,原花青素的纯度为87.9%,该方法能够从慕萨莱思酒中得到纯度较高的原花青素,为原花青素的进一步研究奠定了基础。     

超声辅助酸性乙醇提取紫甘薯花青素的响应面法优化工艺

目的 利用超声辅助酸性乙醇法优化紫甘薯花青素的提取工艺。方法 通过响应面优化法, 以紫甘薯花青素含量为指标进行超声辅助提取, 考察不同因素对紫甘薯花青素提取效果的影响, 用优化的最佳提取工艺, 与不超声传统浸提方法进行比较。结果 最佳提取工艺为:提取液pH 0.9, 超声温度73 ℃, 超声功率153 W, 液料比27 (mL/g), 乙醇浓度40%, 超声时间40 min, 经验证试验最终得到紫甘薯花青素含量为(2.74±0.01) mg/g, 与预测值2.77 mg/g接近, 相对误差为1.08%, 传统浸提得到紫甘薯花青素含量为(1.46±0.01) mg/g。结论 在最佳工艺条件下, 超声辅助提取与传统方法相比, 紫甘薯花青素的提取量得到了提高。     

金刺梨皮原花青素的提取及抗氧化活性研究

通过单因素试验和响应面试验优化超声波辅助提取金刺梨皮原花青素的提取工艺参数。结果表明,超声温度对金刺梨皮原花青素提取率的影响最大,其次是料液比和乙醇体积分数,超声时间对提取率的影响极小。在超声温度68℃、料液比1∶63(g/m L)、乙醇体积分数49%、超声时间15 min的条件下平行提取2次,金刺梨皮原花青素提取率为15.00%,与模型理论预测值相近,所得金刺梨皮原花青素粗提取物对DPPH·的IC50为4.0 mg/L。     

高黎贡山紫果西番莲果皮中原花青素的提取工艺及其稳定性

以高黎贡山紫果西番莲果皮为试验原料,通过微波辅助法考察乙醇浓度、料液比、微波功率和微波时间对原花青素得率的影响,并在单因素试验的基础上,采用响应面法对其提取工艺进行优化。同时,研究光照条件、温度、食品添加剂种类对原花青素提取液稳定性的影响。结果表明：各因素对西番莲果皮原花青素得率影响的主次顺序为微波功率＞乙醇浓度＞料液比＞微波时间;最佳提取条件为乙醇浓度59%,料液比1∶31（g/mL）、微波功率470 W、微波时间82 s,在此条件下原花青素得率为5.38%。稳定性试验结果表明,紫果西番莲果皮原花青素在光照尤其是强紫外线和温度高于60℃的条件下稳定性较差,添加蔗糖、山梨酸钾对其无明显影响,添加柠檬酸、维生素C对其有一定的增色作用。     

响应面优化微波提取黑糯玉米中原花青素的工艺研究

通过单因素试验,研究液料比、微波功率、微波时间、乙醇浓度对微波提取黑糯玉米原花青素的影响,在单因素试验基础上,应用响应面分析法对微波提取原花青素工艺优化。结果表明,微波提取黑糯玉米原花青素的最佳工艺参数为液料比68:1 m L/g、微波功率320 W、微波时间122 s,按照该工艺条件,可得黑糯玉米原花青素提取率为3.4317 mg/g。     

响应面分析法优化紫薯花青素提取工艺

以紫甘薯花青素为原料,采用柠檬酸水溶液为提取剂,分别研究提取剂浓度、浸提温度、浸提时间和料液比对花青素提取率的影响。在此基础上,采用3因素3水平响应面分析法,以吸光度为响应值,探讨浸提温度、浸提时间和料液比对紫薯花青素提取的影响并对提取工艺进行优化。紫薯花青素在波长为524nm处有最大吸收峰。单因素实验证明当柠檬酸浓度为5%、浸提温度为50℃、浸提时间为4h、料液比为1∶20g/mL时花青素提取率达到最大。响应面分析证明对花青素提取率影响大小的顺序为料液比、提取温度和提取时间。响应面分析法确定紫薯花青素最佳提取工艺参数为:提取温度46℃,提取时间6h,料液比1∶23g/mL,在此条件下花青素含量为159mg/100g。     

蓝莓酒中原花青素提取工艺研究

为准确地掌握蓝莓酒中原花青素的有效含量,优化蓝莓酒中原花青素的提取工艺,该研究采用乙醇浸提法提取蓝莓酒中原花青素,并利用单因素试验及响应面试验对蓝莓酒中原花青素的提取工艺进行优化。结果表明,最佳提取工艺条件为：提取时间57 min,料液比1∶7（g∶mL）,乙醇体积分数67.0%,提取温度55 ℃。在此最佳条件下,原花青素平均得率为4.86 mg/g。     

甘蔗皮原花青素的提取及抗氧化活性研究

以甘蔗皮为原料,采用超声辅助提取法,通过单因素试验考察了料液比、浸泡时间、温度、超声时间和乙醇体积分数对甘蔗皮原花青素提取率的影响,进一步通过正交试验优化了提取工艺,并研究了原花青素的体外总抗氧化活性。结果表明:最佳提取工艺条件为料液比1∶30(g/mL),浸泡时间50 min,温度50℃,超声时间30min,乙醇体积分数40%,平均提取率23.15mg/g,抗氧化试验结果表明:原花青素的抗氧化活性随着浓度的增大呈线性增强。该研究为甘蔗皮中花色苷的进一步研究提供了理论依据。     

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.     

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.     

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.     

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.