黄精中水浸出物、多糖和皂苷综合提取工艺优化

以黄精为原料,采用单因素和正交试验研究浸提温度、料液比和时间对水浸出物、多糖和皂苷提取量的影响。单因素实验得出:影响较为显著的因素是浸提温度和料液比,时间对综合提取影响较小;正交试验分析得出:提取最佳工艺条件为浸提温度80℃,料液比1∶30(g∶mL),浸提时间3 h。在此优化条件下,水浸出物、多糖和皂苷提取量为67.92%,25.82%和6.64%。     

百香果中番茄红素提取工艺优化研究

该研究以百香果作为番茄红素提取的原材料,设置单因素试验和正交试验,从而研究其最佳的提取工艺。单因素试验设置5个因素,分别为:预处理方式、提取剂、提取时间、提取温度、液料比;在单因素试验结果的基础上,从中选取3个因素(提取时间、提取温度、液料比)设计正交试验。结合单因素试验和正交试验结果,研究表明:影响番茄红素提取量的因素中,液料比为主要影响因素,提取时间和提取温度为次要影响因素且影响效果相近;最优的预处理方法为浆果破碎后15 000 r/min离心15 min,最佳提取工艺为:丙酮-正己烷2∶1(体积比)做提取剂,液料比为3∶1(mL/g),在35℃恒温振荡培养箱中提取3 h。     

新疆阿克苏地区骏枣中多糖提取工艺研究

在单因素试验的基础上,研究浸提时间、浸提温度和液料比三个关键参数对骏枣多糖提取量的影响,以确定提取工艺。采用三因子二次通用旋转设计,以多糖提取量为评价指标,对多糖提取条件进行优化。结果表明,对骏枣多糖提取量影响由大到小依次是:液料比>浸提温度>浸提时间,得出最佳提取工艺为:浸提时间、浸提温度和液料比分别为5.5 h,77.7℃,14.4∶1。其中浸提时间和浸提温度之间、浸提时间和液料比之间存在显著的交互效应。     

苦瓜叶绿素提取工艺研究

以叶绿素提取量为指标,采用提取溶剂、浸提时间、液料比、温度的单因素试验和三因素三水平正交试验法优化了苦瓜叶绿素的提取工艺条件。结果表明,影响叶绿素提取的主次因素为浸提时间>液料比>温度,并且浸提时间、液料比、温度的影响都达到了极显著水平;叶绿素最佳提取工艺条件为:以丙酮、无水乙醇及水比例为4.5∶4.5∶1的混合溶液作提取溶剂,浸提时间为3h,液料比为10∶1,温度为60℃。在最佳工艺条件下,叶绿素提取量可达0.0317mg/g。     

响应面法优化苦菜蛋白质提取工艺

以苦菜为原料,采用盐溶、酸热综合方法提取苦菜蛋白质,以苦菜蛋白质提取量为指标,通过单因素试验分别考察pH、料液比、提取温度、提取时间等4个因素对苦菜蛋白质提取量的影响程度。结果表明,试验因素影响顺序依次为料液比>提取温度>提取时间>pH。苦菜蛋白质最佳提取工艺条件为pH 3.2,料液比1∶26 g/mL,提取温度65℃,提取时间2.5 h,在此条件下,苦菜蛋白质的提取量为3.54 mg/g,可为苦菜蛋白质生产应用提供参考。     

张氏马尾藻甘露醇的提取工艺

为优化张氏马尾藻甘露醇的提取工艺,研究分析浸提温度、料液比以及浸提时间对甘露醇提取效果的影响,通过单因素试验和正交试验得到提取甘露醇的最佳工艺参数：浸提温度100℃,料液比1∶100（g/mL）,浸提时间2.0 h。在此最佳工艺条件下,甘露醇提取量达5.636 mg/g。此外,对提取效果影响最大的因素是浸提温度,其次是料液比,影响最小的是浸提时间。     

雪菊中抗氧化活性物质的提取工艺研究

通过单因素实验和正交试验,考察不同因素如提取剂浓度、提取温度、提取时间、料液比等对雪菊中抗氧化成分提取效果的影响,确定最佳提取工艺条件。结果表明:在超声提取工艺下,影响提取效果的主次因素为料液比提取温度提取溶剂提取时间,最佳提取工艺条件为料液比1∶8、提取温度65℃、提取溶剂70%乙醇、提取时间3.5h。     

吸附法提取二氢槲皮素的研究

以落叶松木屑为原料,以水为溶剂,聚酰胺为吸附剂提取二氢槲皮素,考察了提取温度、提取时间、液料比、聚酰胺添加量等因素对提取率的影响,通过单因素分析和正交试验设计确定了最佳提取条件:提取温度90℃、提取时间1h、液料比18∶1、聚酰胺添加量为原料的23%,在此条件下二氢槲皮素的提取率为0.814%。     

沙苑子中抗氧化活性物质的提取工艺研究

采用单因素实验结合正交试验的方法,考察提取溶剂浓度、提取温度、提取时间、料液比等因素对沙苑子中抗氧化活性物质提取效果的影响.结果表明,在加热搅拌提取工艺下,影响最大的因素为料液比,其次为提取温度,提取时间相对影响较小.确定沙苑子中抗氧化活性物质的最佳提取工艺条件∶料液比1∶32、提取温度70℃、提取溶剂45％乙醇、提取时间30 min.     

石耳多糖的提取工艺研究

采用单因素试验和正交试验设计,探讨提取时间、料液比和提取温度对石耳多糖提取率的影响,筛选出了最佳提取工艺。结果表明,影响石耳多糖提取率的主次因素为料液比、提取温度及提取时间;石耳多糖最佳提取工艺条件为:提取温度80℃,提取时间4h,料液比1∶10。在此工艺条件下,水溶性石耳多糖的提取率为4.63%。     

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.     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

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.