微波法提取决明子红色素的工艺研究

以决明子红色素浸提率为指标,采用单因素试验法和正交试验法考察了提取剂的类型、料液比、微波功率、萃取时间、次数5个因素。对影响决明子红色素提取的工艺条件进行优化研究。试验结果表明：对微波提取决明子红色素的影响顺序依次为：提取时间〉微波功率〉提取次数〉料液比;优化工艺条件为提取时间4min,微波功率为320W,提取次数为3次,料液比为1：40,溶剂是乙酸乙酯。该条件下进行验证试验,决明子红色素浸提率可达91％。     

响应面优化提取决明子游离蒽醌工艺

通过超声波提取对决明子中游离蒽醌的工艺条件进行探讨,研究乙醇体积分数、超声波温度、超声波时间和料液比对游离蒽醌提取率的影响。通过响应面试验方法对决明子中游离蒽醌的超声波提取工艺条件进行优化。结果表明,游离蒽醌提取的最佳工艺条件：以80%乙醇溶液为超声提取溶剂、液料比15:1(mL/g)、提取温度65℃、提取时间30min、超声功率100W,该条件下游离蒽醌的提取率为28.32%。因此采用响应面法优化得到的提取条件准确可靠,并且提取率较高,具有使用价值。     

微波提取茶叶中咖啡因工艺的研究

采用微波提取方法，微波功率为500W，以茶叶中提取咖啡因的含量为考察指标，研究提取溶剂浓度、料液比、提取时间等因素对咖啡因提取率的影响。通过正交试验，确定微波提取茶叶中咖啡因的最佳工艺条件为：提取溶剂50％乙醇，料液比1：8，提取温度180℃，提取时间14min。     

超声波强化提取决明子活性成分

对超声波提取决明子中蒽醌类化合物的工艺条件进行了探讨,研究了料液比、乙醇浓度、浸泡时间和超声波提取时间等对蒽醌类成分提取率的影响。结果表明,最佳工艺条件为:料液比为0.005g/mL,用体积分数80%的乙醇溶液浸泡决明子3h,在400W的超声功率下提取80min后, 总蒽醌和游离蒽醌的提取率可达质量百分数0.596%和0.181%;其提取率明显比加热回流法和水煎煮法要高。     

微波辅助提取花生壳总黄酮工艺研究

研究微波辅助提取花生壳中黄酮工艺,考察微波温度、料液比、乙醇浓度和微波时间各因素对总黄酮提取率影响,并通过响应面法优化提取工艺.结果表明,提取花生壳黄酮最佳工艺条件为:微波温度73℃、液料比19 ml/g、微波时间358 s、乙醇浓度80％,在此条件下,总黄酮提取率为13.701 mg/g.     

微波法萃取橘皮中果胶的研究

以橘皮为原料在微波条件下提取果胶进行了研究，探讨盐析pH值、微波加热时间、硫酸铝用量、液料比、盐析温度、盐析时间等因素对果胶产率的影响，结果表明：微波法提取果胶的最佳工艺条件为盐析pH5．0，微波力加热时间5min，硫酸铝用量2．5g，液料比16mL／g，盐析温度60％，盐析时间60min，果胶平均得率25％。     

微波辅助提取苹果籽油的工艺研究

采用正交设计法研究了微波加热时间、料液比和微波加热温度对苹果籽油得率的影响,结果得出最佳提取工艺条件为：微波加热时间3min、料液比1：24、微波加热温度50℃。在此条件下,苹果籽油得率为25．51％。     

决明子中蒽醌化合物的提取工艺研究

通过正交实验对决明子中蒽醌化合物的提取工艺条件进行优选,确定了最佳的提取条件为乙醇浓度70%(V/V),温度50℃,固液比125,提取时间为1.5h,蒽醌得率为8.05mg/g原料。提取物中总蒽醌化合物含量为67.6mg/g干重,利用HPLC方法确定了提取物中9种蒽醌化合物的含量。     

微波——乙醇提取苦瓜总皂甙的工艺研究

实验研究了微波功率、乙醇浓度、料液比、提取时间4个工艺条件对苦瓜总皂甙提取效果的影响,在单因素实验的基础上进行了正交实验,优化了工艺参数,最终确定微波——乙醇法提取苦瓜总皂甙的最佳工艺条件为：微波功率320W,乙醇浓度70％,料液比1：30,提取时间4min。     

响应面法优化决明子总蒽醌的超声辅助提取工艺研究

采用响应面法优化决明子总蒽醌的超声辅助提取工艺。在单因素试验基础上,利用响应面分析法,以料水比、超声时间、提取次数、提取温度为自变量,以总蒽醌提取得率为因变量,对决明子总蒽醌的超声辅助提取工艺进行优化,得出回归方程预测模型。结果表明最佳超声辅助提取工艺条件为:料水比1∶42(g/mL),超声时间32 min,提取次数3次,提取温度53℃,在此条件下,决明子总蒽醌的得率为74.51%。     

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.