正交试验法优化黑米黑色素的超声辅助提取工艺

以黑米为原料,优化黑色素的最佳超声辅助提取工艺。采用正交试验法,研究超声波功率、浸提时间、浸提剂体积分数及料液比(黑米︰乙醇溶液,m/V)对黑米色素提取率的影响。结果表明：在所考察的因素中,黑米黑色素的最佳提取工艺为A3B1C3D3。浸提黑色素宜选体积分数80% 的乙醇溶液作为提取剂,超声波作用时间50min,料液比1:32,超声功率250W,该优化方法的提取率为4.5%,比传统的索式提取法的提取率提高了近3 倍。     

超声波辅助提取潮州柑果皮色素的工艺优化

本研究通过单因素试验和L9(33)正交试验对超声波辅助提取潮州柑果皮色素的工艺进行了优化。结果表明:影响潮州柑果皮色素超声波提取的主要因素为超声波提取温度,其次是超声波功率,再次是提取时间;优选方案为:70%乙醇为浸提剂,浸提温度50℃,超声波功率400W,浸提时间25min;超声波辅助提取潮州柑果皮色素的效率明显高于常规提取法。     

正交实验法优选花椒多酚的超声波辅助提取工艺

采用超声波辅助提取法浸提花椒中的多酚类化合物,分别利用单因素实验和正交实验设计优化花椒多酚的浸提工艺参数条件。结果表明:提取剂(乙醇)的浓度对花椒多酚的提取具有显著性影响,花椒多酚超声辅助提取的最佳工艺条件为乙醇浓度60%,料液比1∶40,提取温度60℃,提取时间60min,按照此工艺参数条件浸提花椒多酚,多酚提取率高达(7.05±0.03)%。验证实验表明:正交实验法优化得到的花椒多酚超声波辅助提取工艺稳定可行,可作为花椒多酚提取的一种有效手段。     

正交实验法优选丁香总黄酮的超声波辅助提取工艺

采用超声波辅助提取法浸提丁香中的黄酮类化合物,分别利用单因素实验和正交实验设计优化丁香总黄酮的浸提工艺参数条件。结果表明:提取剂(乙醇)的浓度对丁香总黄酮的提取具有显著性影响,丁香总黄酮超声辅助提取的最佳工艺条件为乙醇浓度70%,提取温度80℃,料液比1∶40,提取时间90min,按照此工艺参数条件浸提丁香总黄酮,提取率高达(8.51±0.03)%。验证实验表明:正交实验法优化得到的丁香总黄酮超声波辅助提取工艺稳定可行,可作为丁香总黄酮提取的一种有效手段。     

荸荠皮色素两种提取方法对比研究

以荸荠皮为原料,采用乙醇浸提法和超声波辅助提取法提取荸荠皮色素,利用正交试验优化两种提取方法的最佳提取工艺条件。结果表明:提取温度为60℃,乙醇浓度为60%,pH为2,超声时间为60min,以40kHz频率的超声波辅助提取条件下,荸荠皮色素提取后的吸光度为1.409。与乙醇浸提法相比,超声波辅助提取法的提取时间缩短了50%,提取率提高了8.6%。     

天然千日红色素提取工艺研究

分别采用常规提取法和超声波提取法对千日红色素的提取条件进行了探讨.结果表明,常规提取的最佳工艺条件是:以体积分数为10％的乙醇为浸提剂,按每克干燥花瓣加浸提剂80mL的比例投料,在温度40℃下,浸提时间为4h.超声波提取的最佳工艺条件是:以体积分数为20％的乙醇为浸提剂,按每克干燥花瓣加浸提剂80mL的比例投料,于超声波清洗器浸提50min.与常规提取法相比,超声波提取千日红色素的每次提取时间由4h减小为50min.     

超声波辅助法提取月季花红色素的最佳工艺研究

利用酸性乙醇作为提取剂,采用超声波辅助法提取月季花红色素,通过不同的浸提温度、溶剂浓度、超声波时问、超声波功率、超声波频率对月季花红色素提取工艺进行了研究.月季花红色素的入max为524nm.单因素和正交实验结果表明:超声波提取时间、超声波功率对月季花红色素的提取效果影响较大,超声波频率及乙醇浓度影响不明显.在温度50℃,料液比1:10条件下,超声波辅助法提取月季花红色素的最佳工艺为:以O.1%盐酸-40%的乙醇溶液作为溶剂,超声波时间60min,超声波功率为300W,超声波频率为45kHz,提取率达到55.63%.     

超声波辅助提取山竹壳色素的工艺优化

采用超声波法提取山竹果壳色素,并通过L(934)正交试验优化提取工艺条件。结果表明:色素在可见光区的最大吸收波长为478 nm,最佳提取工艺条件为:以70%乙醇为浸提剂,超声波功率350 W,提取时间40 min,料液比1∶30(g/mL),提取温度70℃,此条件下的色素提取液吸光度值A478为2.26。超声波辅助提取山竹果壳色素的效率明显高于常规提取法。     

不同方法提取甜荞麦麸皮总黄酮研究

为提高荞麦麸皮利用率,采用乙醇浸提法、超声波辅助提取法和微波加热提取法对提取甜荞麦麸皮黄酮类化合物工艺进行研究。实验结果表明,乙醇浸提法最佳工艺条件为:用50倍50%乙醇在70℃水浴中浸提2.5 h,浸提三次,总黄酮得率为2.4195%;超声波辅助提取法最佳工艺条件为:用60倍70%乙醇在70℃下超声波30 min,超声波提取三次,总黄酮得率为2.8953%;微波加热提取法最佳工艺条件为:用40倍50%乙醇在360 W功率下加热90 s,提取两次,总黄酮得率为2.7963%。比较三种方法结果,以超声波辅助提取法较优,更适于工业化生产。     

正交试验优化超声波辅助提取荞麦皮色素工艺

以荞麦皮为原料,色素得率为指标,在单因素试验基础上,采用正交试验设计法优化超声波辅助提取荞麦皮色素工艺,考察料液比、超声时间、乙醇体积分数、超声功率等因素对荞麦皮色素提取率的影响。结果显示,在超声温度80℃下,超声波辅助提取荞麦皮色素最佳提取工艺为:乙醇体积分数50%,超声时间30 min,超声波功率500W,料液比1︰50 (g/mL)。在该优选工艺条件下,荞麦皮色素得率为5.81%(RSD=0.18%)。该工艺条件操作稳定,有较好重复性。     

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.