响应曲面法优化微波辅助提取香菇柄多糖及其 抗氧化活性研究

目的优化香菇柄多糖的微波辅助提取工艺,并研究其抗氧化活性。方法通过单因素试验,选择时间、功率以及料液比为自变量,多糖提取率为响应值,采用响应曲面法设计分析研究各自变量及其交互作用对多糖提取率的影响。经分析模拟得到二次多项式回归方程的预测模型,从而获得最适的提取工艺条件;并采用DPPH法、Fenton反应等方法测定香菇柄多糖的抗氧化活性。结果在提取时间8 min、微波作用功率400W、料液比1:7(m:V)的条件下获得多糖提取率为4.91%;香菇柄多糖具有清除DPPH自由基与羟自由基的能力。结论本研究可为香菇柄的再利用与开发提供参考。     

微波法提取人参多糖及纯化的工艺研究

将微波辅助提取技术应用于人参多糖提取,通过考察单因素及正交实验确定人参多糖的最佳提取工艺条件:微波功率450 W、微波提取时间6 min、料液比1:50,在此条件下多糖提取率为30%,经红外光谱确定所得物质为β-吡喃糖型多糖.与常规方法相比,微波提取法高效、节能、省时.     

响应面法优化微波辅助提取香菇柄槲皮素的工艺研究

目的采用响应面法优化微波辅助提取香菇柄槲皮素的工艺,为进一步开发香菇柄资源提供依据。方法以槲皮素得率为指标,通过单因素试验,研究乙醇浓度、液料比、微波辐射功率和微波辐射时间对槲皮素得率的影响,用响应面分析法对影响槲皮素得率较大的液料比、微波辐射功率和微波辐射时间3个因素进行优化。结果最佳提取工艺参数为乙醇浓度50%、液料比30:1(m L:g)、微波辐射功率385 W、微波辐射时间50 s。在此条件下,通过3次验证试验,测得槲皮素的得率为(0.75±0.02)mg/g。结论采用响应面分析法优化微波辅助提取法提取香菇柄槲皮素的工艺可行。     

微波法辅助提取香菇多糖的工艺研究

为了进一步确定微波技术辅助提取香菇中香菇多糖的工艺,以微波时间、溶液pH、料液比为因素水平,采用单因素与正交分析法研究了其提取工艺。结果表明,香菇多糖的最佳提取条件为:pH值为8,料液比1∶40,微波时间7 min,香菇多糖提取得率可达5.47%。     

鲜品香菇柄中多糖闪式提取工艺优化及抗氧化活性研究

目的:开发香菇柄多糖的工业化生产。方法:以多糖得率为指标,采用均匀设计试验优化提取工艺,采用4种方法测定多糖抗氧化活性并与传统的热水浸提法进行比较。结果:闪式辅助热水浸提法提取香菇柄多糖最优工艺条件为闪式提取时间120 s,液料比(V_去离子水∶m_香菇柄)40∶1 (mL/g),热水浸提时间105 min,温度50℃,提取两次,此条件下多糖得率为(5.03±0.22)%,与模型预测值基本一致,是传统热水浸提法的1.82倍;香菇柄多糖具有较强的Fe³⁺还原能力、总抗氧化能力、羟自由基和DPPH自由基清除能力,且呈量效关系;闪式辅助热水浸提法所得多糖抗氧化活性强于传统热水浸提法。结论:闪式辅助热水浸提有利于香菇柄多糖提取,且能保持其抗氧化活性。     

微波辅助提取香菇柄水溶性膳食纤维的工艺研究

以香菇柄为原料,利用微波辅助法提取其中的水溶性膳食纤维,采用正交试验对香菇柄水溶性膳食纤维的提取工艺进行优化。结果表明,香菇柄水溶性膳食纤维的最佳提取工艺条件为:柠檬酸质量分数为5%、料液比1∶20、微波功率640 W、微波处理时间3 min。在此最佳条件下,香菇柄水溶性膳食纤维的平均得率为10.24%,持水力为2.27 g/g,膨胀力为4.13 m L/g。     

闪式提取香菇柄中麦角甾醇工艺研究

为实现麦角甾醇物质的快速高效利用,考察了闪式提取香菇柄麦角甾醇的工艺,研究了液料比、处理时间和处理电压等因素对麦角甾醇提取效果的影响,在单因素实验的基础上,对闪式提取麦角甾醇最佳条件进行了优化,并与传统热回流法、超声波辅助法进行了比较。优化结果:液料比为20mL/g、提取时间为4min,提取电压为100V,在此条件下,香菇柄麦角甾醇提取率达到2.762mg/g,与传统热回流提取法、超声波提取法相比,闪式提取法显著地降低了单位提取能耗,缩短了提取时间。     

水浴法和微波法提取金针菇下脚料多糖的优化及比较研究

采用水浴法和微波辅助法对金针菇下脚料多糖的提取工艺进行了研究。实验结果表明,水浴料液比、提取温度和提取时间对金针菇下脚料多糖提取率有显著影响,优化的水浴提取工艺条件为料液比1:20,提取温度为80℃,提取时间2.0h,提取率达13.68%;微波提取料液比、微波功率和微波时间对金针菇下脚料多糖提取率有显著影响,优化的微波提取工艺为料液比为1:25,微波功率320W,微波提取时间80s,提取率达13.80%。与传统的水浴法相比,微波提取法效率高、节约能源,应用前景广阔。     

微波提取香菇多糖制备微胶囊的抑菌抗氧化活性研究

香菇多糖具有抗氧化、抗菌、增强免疫力等多种生物活性，具有很高的药用价值和研究价值。文章通过微波辅助进行多糖的提取，运用响应面法优化提取活性成分，并制备香菇多糖β-环糊精微胶囊，延缓香菇多糖释药速度，最大限度地发挥其生物活性。得出最佳提取工艺条件为料液比1∶40、微波功率119 W、微波提取时间4 min。微胶囊的最佳制备工艺为乳化剂添加量0.38%、包埋时间39 min、固形物质量浓度19.5 g/dL。所制备的微胶囊对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌的抑制作用较强。DPPH自由基清除率达65.4%,羟自由基清除率达57.20%,具有较好的抗氧化性。抑菌活性与抗氧化活性与香菇多糖相比有增幅作用。结果表明，通过微波获得的香菇多糖制作的微胶囊作为新型天然抗菌抗氧化剂来使用具有巨大潜力。     

微波辅助提取梵净山阳荷多糖的工艺优化

为了研究微波法辅助提取梵净山阳荷多糖的最佳提取工艺,采用单因素和正交试验,进行研究,得到了微波辅助提取阳荷多糖的最佳提取工艺条件为:微波浸提时间3 min,料液比1∶20(g∶mL),微波功率264W。此条件下微波提取阳荷多糖的提取率为13.01%,RSD为0.44%。与超声波法和常规浸提法比较,微波辅助提取法大大缩短了浸提时间,节约了材料,提高了阳荷多糖的提取率。     

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.