响应面法优化紫苏籽超声辅助提取原花青素工艺研究

为充分利用紫苏资源,优化其籽粕原花青素提取工艺,考察了料液比、乙醇体积分数、超声功率、温度、时间对原花青素得率的影响,并根据Box-Behnken试验设计原理,在单因素试验基础上选择主要影响因素进行响应面试验。响应面优化后提取工艺条件为乙醇体积分数70%、浸提时间0.5 h、浸提温度70 ℃、超声功率100 W、料液比1∶15。在此条件下原花青素得率理论值为0.232%,实测值为0.229%。     

响应面法优化紫苏籽粕超声辅助提取原花青素工艺

为充分利用紫苏资源,优化其籽粕原花青素提取工艺,考察了料液比、乙醇体积分数、超声功率、温度、时间对原花青素得率的影响,并根据Box-Behnken试验设计原理,在单因素试验基础上选择主要影响因素进行响应面试验。响应面优化后提取工艺条件为乙醇体积分数70%、浸提时间0.5 h、浸提温度70℃、超声功率100 W、料液比1∶15。在此条件下原花青素得率理论值为0.232%,实测值为0.229%。     

正交试验优化远志黄酮提取工艺研究

以中药远志为原料,通过超声辅助提取远志中的黄酮,借助正交试验优化黄酮的提取条件,确定因素影响顺序依次为乙醇体积分数提取温度料液比提取时间,终得到远志中黄酮最佳超声提取工艺条件为超声功率400 W、料液比1∶60 (g/m L)、提取温度70℃、乙醇体积分数100%、提取时间10 min。在此条件下,黄酮提取率最高为1.82%。     

泽泻总三萜超声辅助提取工艺优化

以提高泽泻总三萜的提取率为目的,在浸提温度、浸提时间、乙醇体积分数、料液比及超声时间的单因素基础上,采用四因素三水平Box-Behnken响应面试验设计,优选总三萜提取工艺。结果表明:最佳提取条件为乙醇体积分数70%、浸提时间46.00 min,浸提温度57.00℃,料液比1∶14(g/mL),超声时间30 min,该条件下总三萜提取得率为2.98%。     

芡实叶黄酮超声提取工艺优化

通过Plackett-burman设计法研究料液比、超声功率、乙醇体积分数、提取温度和时间5个因素对芡实叶黄酮提取效果的影响,选择影响效果较显著的4个因素——料液比、超声功率、乙醇体积分数、提取时间通过正交试验优化得出超声提取芡实叶黄酮最佳工艺条件为料液比1:25(g/mL)、超声功率175W、乙醇体积分数85%、提取时间40min,在此条件下芡实叶黄酮提取量为90.28mg/g。     

黑木耳中多酚化合物微波提取工艺

采用L9(34)的正交试验设计,系统研究微波提取黑木耳多酚化合物的工艺条件。以微波功率、微波作用时间、料液比和乙醇体积分数为主要考虑因素,确定了黑木耳多酚化合物微波提取的最佳提取条件为微波作用功率450W、微波作用时间120s、料液比1:25、浸提剂乙醇体积分数75%,此条件下的提取率为0.72%。     

响应面优化微波辅助乙醇提取蜂胶黄酮工艺优化

对蜂胶中黄酮类化合物提取工艺条件进行优化。采用单因素试验分析微波时间、微波功率、乙醇体积分数、浸提温度、浸提时间、液料比6个因素对总黄酮得率影响,根据中心组合试验设计原理,采用四因素三水平响应面分析法进行响应面试验,并对各个因素的显著性和交互作用进行分析。结果表明,最优工艺条件为微波时间70s、微波功率282W、乙醇体积分数80%、提取温度77℃、浸提时间12h、液料比25:1(mL/g),在此条件下,蜂胶总黄酮得率为25.08%。     

芦笋老茎中提取芦丁的研究

以芦笋老茎为原料,采用超声波辅助提取和乙醇浸提两种方法,研究提取温度、超声功率、乙醇体积分数和料液比对芦丁提取的影响,通过单因素试验与正交试验优化芦丁提取工艺条件。结果表明:超声波辅助法对芦笋老茎中芦丁得率明显高于乙醇浸提法,超声功率90 W,乙醇体积分数60%,提取温度80℃,料液比1∶25(m∶V)为最佳提取工艺。该条件下芦丁得率为4.53%。     

从残次茶中制备茶多酚的关键技术研究

现今对残次茶的利用和茶多酚的提取工艺不完善,以至于造成残次茶的浪费。因此,研究从残次茶中提取茶多酚的关键技术是很有必要也很有意义的。试验以黑毛茶为原料,乙醇为提取溶剂,采用超声辅助提取的方法提取茶多酚,并通过响应面分析得到最佳工艺条件：超声功率70 W,乙醇体积分数70%,浸提温度65 ℃,浸提时间30 min,料液比1∶25（g∶mL）。在此条件下,茶多酚提取率为7.44%。 关键词：中图分类号：TS202.3 文献标识码：A 文章编号：0254-5071（20１5）06-0094-05 doi:     

微波辅助双水相体系提取碎铜茶中茶多酚的研究

采用微波辅助乙醇-磷酸氢二钾双水相的方法对碎铜茶中茶多酚进行提取,探讨了双水相体系的分配系数、乙醇体积分数、料液比、提取时间、提取温度和微波功率等因素对茶多酚提取的影响,并采用正交试验法进行优化。试验结果表明:乙醇体积分数为40%,料液比为1∶50(g/m L),提取温度为75℃,微波功率为450 W,提取时间为90 s等优化条件下,茶多酚提取率可达47.21%。研究结果可为碎铜茶品质分析和综合开发利用提供科学依据。     

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.     

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.