蕨麻多糖提取及抗氧化活性研究

通过水提法探讨蕨麻多糖适宜的提取工艺,并研究其抗氧化活性。考察料液比、浸提温度、浸提时间对蕨麻多糖含量的影响,在单因素试验的基础上做L9(34)正交试验优化提取工艺参数。通过测定蕨麻多糖总抗氧化能力,清除DPPH、·OH、O2-·自由基的能力来评价其抗氧化活性。研究结果表明,蕨麻多糖适宜的提取工艺参数是:浸提温度90℃、浸提时间2 h、料液比1∶30。在此条件下蕨麻多糖含量为2.54%。蕨麻多糖具有较好的抗氧化能力,对DPPH、·OH、O2-·自由基的IC50分别为5.47,2.62,27.53 mg/mL。本研究结果为蕨麻开发利用奠定理论基础。     

青兰属植物的化学成分及药理作用研究进展

唇形科(Labiatae)青兰属(Dracocephalum)植物约有60种,主要分布于亚洲温带,化学成分主要包括挥发油类、黄酮及黄酮苷类、植物甾醇及三萜类、有机酸及酯类等,具有抗缺氧、抗氧化、保护心血管、抗肿瘤和清除自由基等多种药理作用,近年来对其化学成分的研究受到很大的关注。本文综述主要青兰属植物的化学成分和药理活性的研究进展。     

大理茶的研究进展

大理茶[Camellia taliensis (W.W. Smith) Melchior],为山茶科(Theaceae)山茶属(Camellia)茶组(Sect. Thea)植物,主要分布于我国云南西部、西南部至缅甸北部。研究表明,大理茶可能是栽培大叶茶的野生近缘种,且具有高度的遗传多样性。大理茶的主要化学成分有生物碱类及水解单宁、黄烷-3-醇、简单酚酸、黄酮及黄酮苷等多酚类物质。体外研究结果显示,大理茶的多酚类成分具有较强的抗氧化、酪氨酸酶抑制活性及抑制人外周血白细胞中Ig E生成的活性。该文对近年来大理茶遗传特征、分布状况、化学成分和生物活性研究进行综述,旨在为大理茶的深入研究和开发利用提供参考依据。     

南药巴戟天多糖的研究进展

巴戟天是我国著名的四大南药之一,多糖是南药巴戟天的主要功能因子之一,具有多种生理活性。近年来国内外对巴戟天化学成分和药理活性方面的研究进行了大量工作。对巴戟天化学成分及其药理的研究进展已有文献报道,但对巴戟天多糖这一重要活性物质未见有详尽的报道。为了进一步研究和开发利用该植物,对巴戟天多糖成分的药理活性、分离纯化、结构分析、含量等方面的研究进展进行综述。     

乙醇/硫酸铵双水相体系提取蕨麻多糖及其抑菌抗氧化活性

利用乙醇/(NH₄)₂SO₄在水溶液中形成的双水相体系作为多糖提取剂,采用响应曲面结合BBD中心组合实验设计,优化了蕨麻多糖双水相提取工艺;以滤纸片扩散半径作为抑菌活性考察指标;采用硫酸亚铁-过氧化氢-水杨酸氧化法和焦性没食子酸自氧化化法考察蕨麻多糖对活性自由基的清除能力。实验结果表明,在最佳提取条件下(1∶35 (g/mL),55 ℃,60 min),蕨麻多糖得率(14.46%±0.12%);抑菌实验结果表明,蕨麻多糖对金黄色葡萄球菌和大肠杆菌属于抑菌高敏感型,对枯草芽孢杆菌属于抑制中度敏感型;蕨麻多糖对三种菌的抑制作用说明,多糖具有一定的抑制细菌活性,且对于不同的菌种的抑制作用具有选择性。抗氧化活性研究表明,蕨麻多糖具有清除自由基的能力,对·OH及O₂-·的清除率分别为(76.38%±0.21%)和(25.01%±0.14%);对应的极限浓度分别为3.6 mg/mL和3.0 mg/mL。以上实验结果说明,通过响应曲面优化结合BBD实验设计,能够确定蕨麻多糖提取因素与得率之间的二次函数模型,为多糖的提取提供了定性与定量评价指标;同时蕨麻的体外抑菌抗氧化活性表明,蕨麻多糖具有一定的体外抑菌抗氧化活性。     

梅花草属化学成分与药理活性研究进展

梅花草属植物多为草本植物,具有清热润肺、补虚益气等作用,传统中医多用其治疗咽喉肿痛、肺结核梅等,临床多用于治疗一些肿瘤疾病。本文综述了梅花草属植物的化学成分及其药理活性研究,以期为梅花草属植物的进一步研究和开发利用提供参考。一、化学成分1.萜类化合物。梅花草属中研究较多的主要是倍半萜类化合物,具体结构见图1。     

竹叶椒生物碱和木脂素化学成分及药理活性研究进展

竹叶花椒在我国是一种常见的花椒属药食两用植物,分布于我国大部分地区.本文结合近些年的文献资料,阐述竹叶花椒生物碱和木脂素化学成分和药理活性研究成果,为该植物进一步开发利用提供参考.     

沙蓬的研究进展

沙蓬(Agriophyllum squarrosum (L.) Moq.)为藜科一年生草本植物,主要分布于我国西北荒漠地区,具有重要的生态意义,被誉为"固沙先锋"。沙蓬地上部分为一种蒙药,具有清热、解毒的功效。沙蓬种子——沙米营养丰富,为一种天然的减肥食品。现代药理学研究发现沙蓬含有黄酮、三萜、香豆素、甾醇、生物碱等次生代谢产物,具有抗糖尿病、抗氧化、降血脂等作用。本文主要针对沙蓬的化学成分、药理活性及营养成分的研究概况进行综述,为沙生植物——沙蓬的开发利用提供参考。     

蔷薇科火棘属和蔷薇属植物研究进展

火棘属和蔷薇属植物主要含挥发油及三萜、黄酮、鞣质、多糖、皂苷以及氨基酸等化学成分,具有酪氨酸酶抑制活性、抗氧化活性、免疫调节和预防肿瘤等作用。通过对火棘及蔷薇属植物的化学成分、活性及应用研究综述,以期为进一步研究和开发提供参考。     

百香果化学成分及药理活性研究进展

西番莲植物百香果(Passiflora edulis Sims)生长于热带地区,在欧洲及南美洲国家常作为一种民间用药,用于治疗焦虑、喘咳、失眠等。近年来,国内外学者对百香果、百香果汁以及副产物(果皮、果叶、种籽)进行了研究,发现百香果主要含有黄酮类、三萜类、生物碱等,具有抗氧化、抗菌、神经保护作用等多种生物活性。本文综述近年来百香果及其副产物的化学成分、药理活性的研究进展,为百香果及其副产物的进一步综合开发利用提供参考。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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.     

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.     

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.     

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.     

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.