紫甘薯花色苷色素的抗氧化性与抑菌作用

采用溶剂浸提法提取紫甘薯花色苷色素,通过自由基体系研究其抗氧化性,并用牛津杯法测定紫甘薯花色苷色素对大肠杆菌和金黄色葡萄球菌的抑制作用。结果表明:紫甘薯花色苷色素对·OH,O2-·和DPPH·3种自由基均有一定的清除能力,在实验浓度范围内,最高清除率分别为55.83%,62.14%和83.21%。紫甘薯花色苷色素对大肠杆菌和金黄色葡萄球菌的最小抑菌浓度分别为1000,250μg/mL,抑菌效果随着紫甘薯花色苷色素浓度的增大而变显著。     

紫甘薯花色苷制备及其抑制3T3-L1前脂肪细胞生长增殖研究

目的:制备紫甘薯花色苷提取物并分析其主要成分,研究其对3T3-L1前脂肪细胞生长增殖的抑制作用。方法:应用响应曲面法优化提取条件;用高效液相色谱法(HPLC)分析其主要成分;以3T3-L1前脂肪细胞为体外模型,利用MTT法得到最佳铺板密度,得到细胞生长曲线,从而在最佳密度和对数生长期检测不同浓度紫甘薯花色苷提取物对3T3-L1前脂肪细胞的增殖的影响。结果:花色苷提取物总量达到39.79 mg/g;选择细胞接板密度为5×103 cfu/mL,细胞铺板12h之后继续培养24 h,紫甘薯花色苷从最低质量浓度15.625μg/mL时即相对于空白组能显著抑制3T3-L1前脂肪细胞生长增殖的作用(P0.05)且具有剂量效应关系,紫甘薯花色苷半数抑制浓度IC50为(413.853±2.617)μg/mL。结论:体外细胞实验显示紫甘薯花色苷具有抑制脂肪细胞生长增殖,提示紫甘薯花色苷具有预防肥胖的作用。     

水提紫甘薯色素废渣中花色苷及总黄酮生物活性的研究

本研究对水提紫甘薯色素剩余废渣中的花色苷和总黄酮进行生物活性研究和评价。采用滤纸片扩散法研究两种组分对金黄色葡萄球菌和大肠杆菌的抑制作用;选取DPPH·体系评价抗氧化活性;采用MTT法检测两种组分对人乳腺癌细胞MDA-MB-231的抑制作用。结果显示:水提紫甘薯色素废渣中花色苷和总黄酮均具有明显抑制金黄色葡萄球菌和大肠杆菌生长、清除DPPH自由基及抵抗人乳腺癌细胞MDA-MB-231生长的作用。花色苷和总黄酮对两种供试菌的最小抑菌浓度分别为400μg/m L和4.0 mg/m L;花色苷对DPPH自由基的半数清除浓度(IC50)为42.32μg/m L,其对照Vc标准品IC50为44.65μg/m L;总黄酮对DPPH自由基的IC50为0.023μg/m L,其对照Vc标准品IC50为0.011μg/m L;花色苷作用于MDA-MB-231细胞24、48、72 h的IC50值分别为202.12、58.01、0.232μg/m L;总黄酮作用于MDA-MB-231细胞24、48、72 h的IC50值分别为0.42、12.05、12.11 mg/m L;本研究为水提紫甘薯色素废渣的综合利用提供了科学依据。     

金属离子和食品添加剂对紫甘薯花色苷稳定性的影响

本文研究了4种金属离子Mg2+、Cu2+、Zn2+、K+以及食品添加剂葡萄糖、蔗糖、山梨酸钾、抗坏血酸对紫甘薯花色苷的影响.结果表明,K+、Zn2+、Mg2+、Cu2+使花色苷的吸光值增加,具有增色作用,有助于稳定紫甘薯花色苷构型.甜味剂葡萄糖、蔗糖均对紫甘薯花色苷有护色作用,山梨酸钾对紫甘薯花色苷无不良影响.抗坏血酸对紫甘薯花色苷有明显的破坏作用,抗坏血酸浓度为0.25mg/mL,50℃下保温3h,紫甘薯花色苷提取液吸光值下降39％.     

1次和2次精制紫甘薯色素理化特性的比较

比较1次和2次精制的紫甘薯色素在不同条件下的理化性质,分析结果显示:2次精制紫甘薯色素具有一般花色苷色素的光谱特性;在pH值3.0以下的水溶液中呈现稳定红色,耐热性和耐光性比1次精制色素降低;Fe3+、抗坏血酸、H2O2和焦亚硫酸钠都会使紫甘薯色素发生降解;添加少量苯甲酸钠对颜色没有明显影响;Mn2+、Mg2+、Cu2+等金属离子和有机酸、蔗糖、葡萄糖、食盐对紫甘薯色素具有增色作用。2次精制色素由于花色苷纯度的增大,体系中除去了一些对色素具有保护作用的非色素多酚黄酮类物质,可能导致其受到的影响略高于1次精制色素。     

紫甘薯花色苷制备及其抗猪传染性胃肠炎病毒(TGEV)活性的研究

为研究紫甘薯花色苷对猪传染性胃肠炎病毒(TGEV)的抑制作用,实验纯化了紫甘薯花色苷提取物,并采用液质联机的方法鉴定其结构组成;将制备的花色苷提取物作用于侵染TGEV的猪睾丸(ST)细胞,研究对TGEV诱导ST细胞的形态学变化和凋亡情况的影响,揭示花色苷对TGEV的预防和治疗效果。结果表明:紫甘薯花色苷提取物中主要含8种花色苷。花色苷质量浓度低于60μg/mL时,ST细胞生长良好且无细胞毒性;接种TGEV后,20μg/mL的花色苷就能抑制TGEV的增殖,且在安全浓度范围内抑制程度成剂量关系。在此体外实验中,花色苷对TGEV的预防效果比治疗效果更明显。结论:紫甘薯花色苷在20～60μg/mL质量浓度范围内对TGEV有很好的抗病毒功效。     

加工方法对紫甘薯花色苷含量及组成的影响

目的:研究烤、炸和蒸3种加工方法对紫甘薯花色苷的影响.方法:采用HPLC-MS法测定3种加工方法对紫甘薯花色苷含量及其组成的变化.结果:3种加工方法均可降低紫甘薯花色苷含量,其花色苷残余率:炸薯93.7％,蒸薯87.1％和烤薯60.0％.紫甘薯中双酰化的花色苷稳定性高于单酰化花色苷,咖啡酸酰化的花色苷组分稳定性高于对羟基苯甲酸酰化花色苷.结论:炸和蒸加工方法可有效维持紫甘薯花色苷含量.     

水提紫甘薯色素废渣花色苷提取工艺研究

目的研究水提紫甘薯色素废渣花色苷的提取工艺,旨在为紫甘薯废渣的综合开发利用提供参考依据。方法采用溶液浸提法、超声波辅助法、微波萃取法对水提紫甘薯色素废渣中的花色苷进行提取研究,通过单因素实验和正交实验确定最佳提取方法及工艺条件。结果水提紫甘薯色素废渣花色苷最佳提取方法为微波萃取法,其最佳提取工艺:pH 1.5柠檬酸溶液,料液比1:20,微波功率708 W,时间4 min。在此条件下累计提取6次并测得水提紫甘薯色素废渣中花色苷总量178.33 mg/100 g。最佳提取次数为2次。结论水提紫甘薯色素废渣花色苷含量较高,可考虑将其应用于食品工业、生态动物饲料生产等行业。     

紫甘薯花色苷生产中紫薯蛋白的分离与富集

为了将紫甘薯色素提取液中的花色苷与蛋白分离,选择不同型号的大孔吸附树脂对紫甘薯色素提取液进行了吸附与解吸实验,筛选出特异性吸附提取液中色素的树脂.并利用大孔吸附树脂对流出液中紫甘薯蛋白进行富集.实验结果表明:ADS-7型树脂能有效将提取液中的花色苷与蛋白分离,分离程度达70%以上;流出液以1BV/h、2mg/mL流经树...     

紫甘薯花色苷降血糖功效研究

本文研究了由双酶法提取的紫甘薯花色苷的降血糖功效。通过动物实验,研究了紫甘薯花色苷对正常小鼠餐后血糖的影响。实验结果表明：紫甘薯花色苷高、中剂量组可有效抑制餐后血糖的升高。将四氧嘧啶诱导的高血糖小鼠模型按血糖分组,连续给药30d后,研究紫甘薯花色苷对高血糖小鼠血糖的影响,结果显示：紫甘薯花色苷高、中剂量组可显著缓解血糖升高,血清抗氧化指标SOD,MDA,GSH—Px的测定结果显示,高、中剂量组与模型组相比可显著改善体内抗氧化体系。     

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.     

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.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the