超临界CO2流体萃取荷叶总生物碱工艺研究

采用超临界CO2流体萃取技术研究荷叶总生物碱的提取工艺条件.以萃取温度、萃取压力、夹带剂流速、萃取时间为工艺参数,通过单因素试验和正交试验相结合的方法,确定超临界CO2流体萃取荷叶总生物碱的最佳工艺,即:萃取温度55℃,萃取压力20MPa,夹带剂流速0.2 mL/min,萃取时间2h.各因素影响荷叶总生物碱得率的次序为:萃取温度＞萃取时间＞萃取压力＞夹带剂流速.最佳工艺验证试验的荷叶总生物碱得率为318.45μg/g.     

超声超临界流体萃取烟叶中的烟碱

考察了夹带剂(75%乙醇)用量、萃取压力、萃取温度、CO2流量、萃取时间和超声功率密度对超声强化超临界CO2萃取烟叶中烟碱的影响.结果表明,超声强化超临界流体CO2萃取烟叶中烟碱的较佳工艺条件为:萃取压力21 Mpa、萃取温度50 ℃、萃取时间2.5 h、CO2流量3.0 L/h、夹带剂用量4 mL/g烟末、超声功率密度100 W/L、频率20 kHz.在此条件萃取下,烟碱萃取率超过94%.     

超临界CO_2流体萃取核桃油研究

本文研究应用超临界CO2流体萃取技术提取核桃油工艺。采用四因素三水平正交试验,考 察压力、温度、萃取时间、CO2流量四因素对核桃油萃取率影响效果。最佳萃取条件为:压 力30 Mpa,温度50℃,时间4h,CO2流量25kg/h,在此条件下萃取率可达52.4％。利用 GC/MS分析核桃油成分组成,比较超临界CO2萃取油样和乙醚萃取油样的理化性质。     

超临界CO2萃取车前草中熊果酸的工艺研究

目的:研究超临界CO2萃取车前草中熊果酸的工艺条件.方法:探讨萃取压力、萃取温度、萃取时间、夹带剂类型及用量对熊果酸收率的影响,确定了超临界CO2萃取车前草中熊果酸的适宜条件.结果:超临界萃取最优条件为萃取压力35 MPa,萃取温度为40℃,选择无水乙醇为夹带剂,夹带剂质量分数为20%,萃取时间2 h,CO2流量为20 L/h,产品的出膏率为3.58%,萃取物中熊果酸的含量为6.93%.结论:该法与传统方法相比,具有操作简便快速,溶剂用量少,有效成分提取率高等优点.     

超临界CO_2流体萃取法提取姜黄素的研究

姜黄素是国内外食品行业允许使用的重要天然色素之一,具有很大的市场潜力。本实验采用超临界CO2流体萃取法提取姜黄中有效成分姜黄素,通过正交实验探讨了原料粒度、萃取压力、萃取温度、萃取时间、CO2流量及夹带剂(95%乙醇)用量等对姜黄素提取效果的影响。结果表明:夹带剂用量和萃取压力是最重要的影响因素,最佳提取条件为原料粒度1.0mm,萃取压力为35MPa,萃取温度40℃,萃取时间3h,CO2流量30L/h,夹带剂用量1mL/g;在最佳萃取条件下,姜黄素含量为14.317mg/g。     

超临界CO2萃取花椒果皮总黄酮的工艺

以七年生花椒果皮为原料,进行超临界CO2萃取分离花椒总黄酮的工艺研究,采用硝酸铝-亚硝酸钠法对萃取物中的总黄酮含量进行了定量测定,重点考察了萃取温度、萃取压力、萃取时间以及夹带剂用量对总黄酮得率的影响.正交实验结果表明,各种因素对花椒萃取率的影响的程度从高到低依次为:萃取温度＞萃取压力＞萃取时间＞夹带剂用量.超临界CO2流体萃取花椒黄酮的优化条件为:萃取温度为50℃,萃取压力35MPa,萃取时间150min,夹带剂用量4mL/g,此时花椒总黄酮提取率为19.574％.     

超临界CO_2流体萃取大马哈鱼籽中DHA和EPA的工艺

以DHA和EPA的提取率、鱼籽油中DHA和EPA的含量为测定指标,分别研究了收集压力、萃取压力、萃取温度、萃取时间和夹带剂用量比例对超临界CO2流体萃取冻干鱼籽粉中DHA和EPA的影响。结果表明:超临界CO2流体萃取冻干鱼籽粉中DHA、EPA最佳条件为:萃取压力20MPa,萃取温度55℃,夹带剂比例1∶4,萃取时间2h,收集压力30MPa,收集温度65℃。在此条件下,DHA的提取率可达55.81%,EPA的提取率可达56.93%,萃取出的鱼籽油中DHA的含量达到161.26mg/g,EPA的含量可达170.03mg/g。     

超临界CO2萃取西瓜籽油的研究

采用超临界CO2流体萃取方法从西瓜籽中提取西瓜籽油.利用正交实验探讨萃取压力、萃取温度、萃取时间、夹带剂用量对西瓜籽油萃取率的影响.结果表明,影响西瓜籽油萃取率的因素主次顺序为:萃取压力>萃取时间>萃取温度> 夹带剂用量;最佳提取条件为萃取压力40 MPa,萃取温度45℃,萃取时间150 min,夹带剂乙醇用量7%.在最佳条件下西瓜籽油萃取率为52.18%.     

超临界CO2和微波萃取核桃油的比较研究

通过超临界CO2萃取核桃油的正交实验和微波萃取核桃油的均匀设计实验,考察影响核桃油萃取的主要因素,寻求最佳萃取工艺条件.研究结果表明,超临界CO2萃取的最佳工艺条件为:萃取压力35 MPa,萃取温度45℃,萃取时间2.5 h,分离温度50℃,CO2流量25 kg/h;在此条件下油脂得率为59.2%.微波萃取最佳工艺条件为:以环己烷为萃取剂,溶料比为3.5:1(W/W),微波功率735 W,每次微波辐射时间60 s,微波辐射累计时间6 min,在此条件下得率为60.4%.比较了不同提取方法对油脂得率和油脂品质的影响.结果表明,微波萃取油脂得率最高,时间最短;超临界CO2萃取的核桃油品质最优,是萃取优质核桃油的首选方法.     

超临界CO2萃取红松子油的研究

研究超临界CO2萃取红松子油的影响因素，在试验条件下，其影响因素次序为萃取压力、夹带剂、萃取温度、萃取时间。最优条件为35MPa，45℃，240min，5％无水乙醇作夹带剂，CO2流量20L／h～25L／h。45oC时，在15MPa和35MPa两种不同的压力下，对比了加入5％无水乙醇作夹带剂与不使用夹带剂时超临界CO2萃取过程中出油量随时间的变化，使用夹带剂后出油量均有提高。     

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.     

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.