金银花主要成分对铜绿假单胞菌多耐药菌株的抑制作用研究

目的 研究金银花主要成分对铜绿假单胞菌质控菌株和多耐药菌株的体外抑菌作用,及金银花有机酸总样与氨基糖苷类抗生素联合使用对多耐药菌株的抑菌效果.方法 平板倍比稀释法测定金银花中主要成分绿原酸、异绿原酸组分和木犀草素以及氨基糖苷类抗生素硫酸阿米卡星和庆大霉素对铜绿假单胞菌质控菌株和耐药菌株的最低抑菌浓度(MIC),在此基础上研究金银花有机酸总样与硫酸阿米卡星联合用药的抑菌效果.结果 金银花主要成分绿原酸、异绿原酸组分和木犀草素对铜绿假单胞菌多耐药菌株的MIC分别为10,5和2.5 mg/mL,对质控菌株的MIC分别为＞10,5和2.5 mg/mL.金银花有机酸总样与氨基糖苷类抗生素联合用药,可降低硫酸阿米卡星对多耐药铜绿假单胞菌的MIC,两者联用有一定的协同作用.结论 金银花主要成分绿原酸、异绿原酸和木犀草素均有抑制铜绿假单胞菌的作用,其中绿原酸对耐药菌株的抑制作用最强.金银花有机酸组分与氨基糖苷类抗生素联合用药,对铜绿假单胞菌多耐药菌株具有协同抑制作用.     

不同产地及品种金银花中绿原酸和木犀草苷含量测定

测定不同产地、品种金银花中绿原酸和木犀草苷的含量。按照2010年版《中国药典》金银花项下规定的HPLC法分别测定各样品中绿原酸和木犀草苷的含量。结果表明13个不同产地来源、品种的金银花中绿原酸和木犀草苷的含量分别在2.23%~3.16%和0.085%~0.193%范围内,均符合药典标准。山东平邑来源金银花的绿原酸和木犀草苷含量明显高于其它产地,其中,以平邑地产金银花质佳。结论:不同产地来源、品种的金银花质量有一定差异,在引种栽培时应选择优良品种。本研究结果可为金银花引种栽培和人工培育提供参考依据。     

金银花叶有效成分的抗氧化活性研究

建立高效液相转换波长法,测定金银花叶粗分物中绿原酸、木犀草素和木犀草苷的含量,绿原酸占水相原液的含量为2.05%,木犀草素、木犀草素在金银花叶粗提物EA相中的含量分别为1.12%、0.57%。以抗坏血酸(Vc)为阳性对照的,用DPPH?法、FRAP法、ORAC法三种体外抗氧化方法来测定和评价金银花叶有效成分的抗氧化作用。结果表明：金银花叶粗提物、粗分物、绿原酸.、木犀草素及木犀草苷均具有良好的抗氧化性,其中木犀草素的抗氧化能力最强,其IC50值为0.01764 mg/mL,还原能力1751.8±13.9 mmol/L,ORAC值23817.44 μmol Trolox/g。其次为粗分30%乙醇洗脱相,其IC50值为0.02548 mg/mL,还原能力933.8±11.6 mmol/L,ORAC值10557.97 μmol Trolox/g,且各物质随着抗氧化剂浓度及纯度的增加,抗氧化性逐渐增强。因此对金银花叶有效成分在抗氧化方面的应用具有广阔的开发利用前景,可作为新型的高效无毒的抗氧化剂。     

燕麦种子萌发过程中提取物的抑菌作用研究

以4种食品腐败菌为指示菌,采用滤纸片法和液体倍比稀释法对裸燕麦(Avena nuda L.)种子萌发过程中不同溶剂提取物的抑菌作用和最低抑菌浓度(MIC)进行了比较研究。试验结果表明,乙酸乙酯提取物的抑菌作用较好,但在种子萌发过程中抑菌效果不同,萌发24 h时燕麦种子的乙酸乙酯提取物的抑菌作用最强,其中对大肠杆菌的抑菌圈直径达(22.31±0.05)mm;其对金黄色葡萄球菌和大肠杆菌的最低抑菌浓度MIC小于6.25%,对鼠伤寒沙门氏菌和肠炎沙门氏菌的最低抑菌浓度MIC小于12.5%,旨为燕麦的综合利用及新型天然防腐剂的研发提供理论依据。     

金银花营养品质评价体系的构建

构建金银花营养品质评价体系，对筛选和发掘金银花优异资源及金银花药食同源综合利用具有重要意义。本研究以138份不同产地的金银花为试验材料，采用高效液相色谱法测定金银花中的绿原酸、芦丁、木犀草苷、异绿原酸A、异绿原酸C、木犀草素的含量；采用紫外分光光度法测定和计算金银花中总黄酮的含量。采用熵权法、灰色关联度分析和主成分分析建立金银花营养品质综合评价函数，通过概率分布建立金银花营养品质综合评分标准。结果表明，138份参试材料的7种营养成分含量各有差异，变异系数为8.32%~71.23%。7种成分均受环境的影响，然而影响程度不同。相关性分析表明，木犀草苷与绿原酸和芦丁均表现出极显著正相关；异绿原酸A与异绿原酸C表现出极显著正相关；木犀草素与异绿原酸A和异绿原酸C均表现出极显著负相关；总黄酮与异绿原酸A和异绿原酸C均表现出极显著正相关，与木犀草素表现出极显著负相关。PCA将7个营养组分指标简化为3个主成分因子，PC1包括异绿原酸A、异绿原酸C和木犀草素；PC2包括绿原酸和木犀草苷；PC3包括芦丁和总黄酮。3个主成分贡献率分别为44.339%，23.930%和18.382%，累计贡献率为86.651%。在此基础上，建立了金银花营养品质综合评价函数和金银花营养品质综合评分6级标准。利用评价体系对金银花资源营养品质进行综合分析，可以得到更加客观的营养评价结果，为筛选营养品质最优的金银花材料提供依据。     

多倍体金银花与二倍体金银花不同部位提取物的抑菌作用及绿原酸含量的比较研究

目的:测定多倍体和二倍体金银花、叶和茎中绿原酸的含量,研究其提取物的抑菌作用。方法:高效液相色谱法(HPLC)和最小抑菌浓度(MIC)测定法。多倍体金银花、叶、茎中绿原酸含量分别为:7.76%、4.61%、0;二倍体为:5.97%、3.94%、0。多倍体金银花、叶提取物对大肠杆菌、藤黄八叠球菌、枯草芽孢杆菌的MIC分别为:250、500、500、500、250、500μg/g,二倍体为:500、1000、500、500、500、1000μg/g。结论:多倍体金银花、叶中绿原酸的含量比二倍体金银花、叶有显著性的提高,多倍体金银花提取物的抑菌作用强于二倍体金银花提取物。多倍体金银花比二倍体金银花具有更高的开发价值。     

七种精油对多重耐药鲍曼不动杆菌的抑制作用

本文研究了肉桂等精油对多重耐药鲍曼不动杆菌(MDRAB)的体外抑菌效果,采用药敏纸片扩散法和微量肉汤稀释法测定其对MDRAB的抑菌圈直径和最小抑菌浓度(MIC),筛选出抑制效果最好的精油和绘制出该精油对MDRAB的动态杀菌曲线。用棋盘稀释法研究MIC值最小的两种精油联合抗MDRAB的效果。结果表明肉桂精油对MDRAB的抑菌效果最强,抑菌圈直径为29.30±1.16 mm,MIC值为0.62μL/mL,且对MDRAB的抑菌活性存在浓度依赖性,另外肉桂精油与薰衣草精油联合抗MDRAB有相加作用,与薄荷精油联合抗MDRAB有部分协同作用;薰衣草精油和薄荷精油也有较强抑菌效果,MIC值依次为1.25μL/mL和2.50μL/mL;丁香精油对MDRAB有中度抑菌活性,MIC值为10μL/mL;冬青精油和绿茶精油对MDRAB的抑菌作用相对较弱,MIC值为20μL/mL;安息香精油对MDRAB的抑制作用很弱甚至无抑制作用。因此,肉桂精油对MDRAB的抑菌效果最强,且对MDRAB的抑菌活性与浓度正相关,另外与薰衣草精油和薄荷精油有联合抗MDRAB作用,为临床用药提供有效指导。     

冠醚交联壳聚糖载纳米银对四种霉菌的防霉性能评价

通过最低抑菌浓度MIC值和抑菌圈法,评价了二苯并-18-冠-6冠醚交联壳聚糖载纳米银(ACTSG)对常现青霉、绳状青霉、产黄青霉、土曲霉的防霉性能。结果表明:ACTSG对四种霉菌的MIC值分别为20 mg/L,5 mg/L,10 mg/L,10 mg/L;培养5 d后,质量浓度为350 mg/L的ACTSG溶液对四种霉菌的抑菌圈直径分别为32.56mm,-(未长霉),◎(抑菌圈未形成),33.86 mm。对绳状青霉的抑制效果最强。以加脂革为试样,培养5 d后,质量浓度为300 mg/L与350 mg/L的ACTSG溶液对混合霉菌的抑菌圈直径分别为25.55 mm和31.27 mm。     

翠云草挥发油成分分析、抗氧化及抗菌效果

目的:对翠云草挥发油进行成分分析、抗氧化及抗菌研究。方法:采用气相色谱-质谱仪(GC-MS)对翠云草挥发油化学成分进行分离鉴定;采用DPPH法,FRAP法和金属离子螯合能力实验评价翠云草挥发油的体外抗氧化活性;用纸片扩散法测定翠云草挥发油的抗菌活性,包括3种革兰氏阳性菌,即金黄色葡萄球菌、粪肠球菌、化脓棒状杆菌,和3种革兰氏阴性菌,即大肠杆菌、铜绿假单胞菌、变形杆菌。结果:从翠云草中分离出52个峰,鉴定出50种成分,已鉴定成分占总面积的98.58%,主要成分有植酮(21.40%)、角鲨烯(8.53%)、棕榈酸(6.71%)、二十八烷(6.03%)等。翠云草具有潜在的抗氧化活性,DPPH自由基清除的IC₅₀值为0.76 mg/mL,铁离子还原能力的FRAP值为0.86 mmol/L,金属离子螯合作用的EC₅₀值为0.71 mg/mL。通过抗菌实验的MIC和MBC结果表明翠云草挥发油对粪肠球菌、化脓棒状杆菌、大肠杆菌和铜绿假单胞菌则具有较好的抗菌活性,其中对粪肠球菌的MIC值为5 μL/mL,MBC值为10 μL/mL;对化脓棒状杆菌的MIC值为10 μL/mL,MBC值为20 μL/mL。结论:本文通过GC-MS分析了翠云草挥发油成分,并首次发现其具有一定的抗氧化活性及抗菌活性。     

金银花药用成分及其土壤污染物含量分析

目的 探究河北省巨鹿县人工栽培模式下金银花药材质量及土壤污染状况。方法 采集巨鹿县7个乡镇不同时期的金银花及其土壤样品,检测金银花中绿原酸、木犀草苷指标含量及其土壤中重金属和农药残留污染水平。结果 金银花样品中绿原酸、木犀草苷含量随着物候期的变化差异显著,呈现先下降后上升的趋势;金银花及其土壤中重金属和农药残留均有不同程度的检出。结论 金银花产量以第一、二茬花为主,占全年总产量的67.3%;对照现行相关标准巨鹿金银花药用指标总体达标,重金属及农残含量未构成质量安全风险。     

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.