寒富苹果渣中多酚类物质超声波辅助提取工艺

以寒富苹果果渣为原料,以一定浓度乙醇溶液为提取剂,利用超声波辅助法提取苹果渣中的多酚。通过对乙醇浓度、超声波功率、超声波时间、料液比等条件进行单因素试验分析,并通过响应面法得出苹果渣中多酚的回归方程。确定多酚类物质的最佳提取工艺条件为乙醇浓度49%,超声波功率为370 W,作用时间为136 s,料液比为1∶30(g∶mL)。实际平均提取率1.71 mg/g。     

超声波辅助提取葡萄皮渣中多酚类物质的研究

葡萄皮渣中含有抗氧化性的多酚类物质,具有很高的营养价值和利用价值,但是在我国的葡萄加工生产中,葡萄皮的利用率却不高。采用超声波辅助法对葡萄皮渣中的多酚进行提取,探讨了料液比、乙醇浓度、p H值、萃取时间、温度以及超声频率等因素对多酚提取率的影响,并通过响应面实验确定了最佳工艺参数为:料液比1∶10、乙醇浓度40%、超声波处理时间30min、萃取温度40℃、p H6、超声频率45KHz,在此条件下提取的葡萄皮渣中多酚含量可达17.79mg/g。实验建立的超声波辅助法可高效提取葡萄皮渣中多酚类物质,对充分利用葡萄资源具有实践指导意义。     

微波法提取苹果渣中多酚的工艺研究

以乙醇作为提取溶剂,研究了微波法提取苹果渣中多酚的工艺条件。主要探讨了溶剂浓度、微波功率、提取时间、料液比、物料颗粒等因素对多酚提取的影响,结果表明,微波法从苹果渣中提取多酚的最佳工艺条件为乙醇浓度60%、物料颗粒40目、液料比1∶10、微波功率350W、提取时间90s,此条件下从苹果渣中提取的多酚浓度可达245.31mg/100g,明显优于回流提取法和超声波提取法。     

超声波辅助提取燕竹笋壳中多酚的工艺优化

以燕竹笋壳为原料,运用超声波辅助提取技术对其中多酚类物质进行提取,以其总多酚得率作为指标,考察超声功率、提取时间、乙醇浓度、料液比对总多酚提取率的影响,并利用响应面法对燕竹笋壳多酚提取工艺进行分析,得到最佳工艺参数为:超声功率200 W,提取时间40.2 min,乙醇浓度42%,料液比1:50.5。在此条件下,燕竹笋壳总多酚的理论提取得率为5.50%,实际平均提取得率为5.57%,理论预测值与实际值相对误差为1.27%。     

超声波辅助提取番石榴中多酚类物质的研究

以番石榴为提取原料,采用超声波辅助提取番石榴多酚。通过对超声波功率、乙醇浓度、料液比、超声时间进行单因素试验,并利用响应面分析得到番石榴中多酚提取率的回归方程。结果表明,番石榴多酚提取的最佳工艺条件为超声波功率350W,乙醇浓度40%,料液比1∶30(m∶V),该条件下多酚的提取得率为4.65mg/g。     

新疆石榴皮多酚提取工艺研究

以新疆石榴皮为原料,采用二次通用旋转回归组合设计对超声波辅助提取石榴皮多酚工艺进行研究.对提取溶剂种类、乙醇浓度、料液比、超声时间、超声波功率等影响多酚得率的因素进行试验.结果表明,其最佳提取工艺条件为乙醇浓度50%,料液比(m∶V )1∶25,超声时间30 min,超声波功率360 W.在此优化条件下,石榴皮多酚得率达到(21.22±0.06)%.     

花生衣多酚的超声波辅助提取工艺研究

以乙醇为溶剂,采用超声波辅助方法提取花生衣多酚.通过单因素试验,研究料液比、乙醇浓度、超声时间、超声温度等因素对多酚提取得率的影响,在此基础上通过正交试验对提取条件进行优化.结果表明:超声波法提取花生衣多酚物质的最佳条件为料液比1∶25、乙醇浓度55％、超声处理时间50 min、超声温度40℃,多酚提取得率为3 699 μg/g.     

黑果腺肋花楸多酚类物质超声波辅助提取工艺的优化

以黑果腺肋花楸为原料,采用超声波辅助乙醇提取法从黑果腺肋花楸中提取多酚物质,并使用福林酚法测定多酚含量。通过单因素试验和正交试验,研究料液比、温度、乙醇浓度、超声时间、超声功率对多酚得率的影响。试验结果表明:最佳提取工艺为乙醇浓度50%、温度40℃、料液比1∶5、超声时间40min、超声功率500 W、多酚得率0.836%。     

响应面优化鸡油菌多酚的超声辅助提取工艺及其抗氧化活性

以鸡油菌为原料获得鸡油菌多酚提取的最佳工艺条件,采用超声波辅助乙醇提取法,以料液比、超声温度、乙醇浓度、超声时间为单因素,利用Box-Behnken方法进行四因素三水平的实验设计优化了多酚最佳提取工艺条件。同时,以超高效液相色谱质谱技术UPLC-MS对鸡油菌中的多酚成分进行了分析,采用DPPH法、ABTS法、FRAP法对多酚进行了体外抗氧化活性评价。此外,比较了乙醇浸提、索式热回流提取与超声波辅助乙醇提取三种方法对鸡油菌多酚含量的差异。结果表明:采用超声波辅助乙醇提取鸡油菌多酚的最佳条件为料液比1:32（g/mL）、超声温度40 ℃、乙醇浓度40%、超声时间21 min;超声辅助提取多酚的量最大,为11.80 mg/g;浸提多酚含量为8.60 mg/g;索式热回流多酚含量为3.60 mg/g。UPLC-MS分析结果表明鸡油菌多酚提取物主要包含没食子酸、咖啡酸和丁香酸酚类成分;与传统方法比较,超声波辅助提取法是一种简单快速高效的多酚提取方法;三种体外抗氧化活性试验表明,鸡油菌多酚具有较强的体外抗氧化活性。     

响应面法优化超声辅助提取核桃叶多酚的工艺研究

首次以陇南核桃叶为原料,运用超声波辅助提取技术对核桃叶中的多酚类物质进行提取,在温度为40℃,超声功率为110W的条件下,考察了料液比、超声时间、乙醇浓度对多酚提取率的影响,并利用响应面法优化了提取工艺,得出最佳工艺参数为:料液比为1∶10,超声提取时间为10min,乙醇浓度为70%,在最佳提取工艺的条件下,核桃多酚的含量可达到4.04mg/g,为核桃叶多酚的进一步开发提供了依据。     

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.