复合酶辅助超声波提取菊苣根总黄酮的工艺优化及其抗氧化活性

目的:菊苣根总黄酮提取工艺条件的优化,并探究其体外抗氧化能力。方法:在单因素实验基础上,选用Box-Behnken试验设计方法,建立以超声时间、液料比、酶解时间、超声功率和复合酶（纤维素酶与果胶酶）的用量为自变量,菊苣根总黄酮得率为因变量的二次回归模型。根据菊苣根总黄酮对ABTS自由基和DPPH自由基的清除效果来判断其体外抗氧化能力。结果:复合酶辅助超声波法提取菊苣根总黄酮的最佳工艺条件为:复合酶用量2.2%、液料比37:1 mL/g、酶解时间66 min、超声功率59 W、超声时间24 min,在此条件下总黄酮得率为5.43 ± 0.12 mg/g。当提取的总黄酮溶液浓度为0.1 mg/mL时,对DPPH、ABTS自由基的清除率分别为84.45%和98.18%,IC₅₀值分别为0.04和0.021 mg/mL。结论:本研究利用响应面法优化了菊苣根总黄酮的提取工艺,建立了总黄酮得率的模拟回归方程,可用于菊苣根总黄酮提取工艺的参数优化。菊苣根总黄酮有着较好的体外抗氧化活性,可用于食品添加剂和开发新的抗氧化药物。     

杏仁及杏仁皮多酚超声提取优化及抗氧化能力差异性研究

为获得杏仁及杏仁皮内多酚提取的最优方案,采用超声波处理样品,以料液比、超声温度、功率和时间为影响因素多酚得率为指标进行研究。结果表明:杏仁多酚超声提取最佳条件为料液比1∶10、超声温度50℃、超声功率400 W,超声时间60 min。而杏仁皮多酚超声提取最佳条件为料液比1∶10、超声温度60℃、超声功率400 W,超声时间60 min。采用还原力、OH、DPPH和ABTS自由基清除率四个抗氧化能力指标对杏仁及杏仁皮多酚的抗氧化能力进行差异性分析,以期为杏仁多酚这一功能性成分的开发提供参考依据。研究结果表明,杏仁多酚抗氧化能力大小与其含量成正比。甜杏仁多酚的还原力、OH和ABTS自由基清除率均高于苦杏仁多酚,而甜苦杏仁多酚的DPPH自由基清除率接近一致,且在0.024 mg/m L浓度时依次为25.4%和23.7%。甜苦杏仁皮多酚抗氧化能力差异不明显,其还原力、DPPH和ABTS自由基清除率三者基本一致,而在0.24 mg/m L浓度时,甜杏仁皮多酚的OH自由基清除率约为苦杏仁皮的2倍。总体来说,甜杏仁多酚的抗氧化能力优于苦杏仁多酚,潜在利用价值更高。     

石吊兰总多酚体外抗氧化活性研究

研究石吊兰总多酚的体外抗氧化活性。采用单因素实验研究提取时间、超声波功率、提取温度、乙醇浓度、提取次数和料液比对总多酚提取率的影响。用还原能力、·OH清除率、DPPH·清除率来考察石吊兰总多酚的体外抗氧化活性。结果表明,超声提取石吊兰总多酚的最佳工艺条件为:提取时间32min,超声波功率为100%,提取温度为25℃,乙醇浓度为80%,提取次数为3次,液料比为20∶1,此时石吊兰总多酚得率为14.0mg GAE/g。此外,石吊兰总多酚的还原能力、对·OH以及DPPH·的清除均高于VC。石吊兰总多酚是天然的抗氧化活性剂和自由基清除剂。     

虫草花多糖提取工艺优化及其抗氧化特性

采用超声辅助法提取虫草花多糖,在单因素试验的基础上,通过L9（34）正交试验优化了虫草花多糖提取工艺;并就虫草花多糖对羟基自由基（·OH）、1,1-苯基-2-苦肼基（DPPH）自由基的清除作用和还原能力进行研究。结果表明：虫草花多糖最佳提取工艺条件为超声功率300 W,液料比30∶1（mL∶g）,超声时间30 min,超声温度45 ℃。在此优化条件下,多糖的平均提取率为3.88%。抗氧化活性试验结果表明,虫草花多糖质量浓度在2.9～14.7 mg/L范围内,随着虫草花多糖质量浓度的增加,其OH、DPPH自由基清除能力及还原能力均逐渐增强,虫草花多糖质量浓度为14.7 mg/L时,对·OH和DPPH·清除率分别达到44.39%和56.34%,说明虫草花多糖具有较强的抗氧化活性。     

分心木黄酮超声-微波协同提取及抗氧化性研究

在单因素试验基础上应用响应面分析法(Box-Benhnken)对核桃分心木中黄酮的提取工艺进行优化并研究其体外抗氧化活性。试验结果表明:最佳提取条件为乙醇浓度为50%,料液比为1∶25.6(g/m L),超声功率为261.8 W,微波功率150 W,提取温度为51.6℃,提取时间为8.5 min,分心木黄酮得率为5.17%。抗氧化活性试验结果表明当分心木黄酮浓度为2 mg/m L时,对·OH和O2-·的最大清除率分别为66.2%、36.9%,而对DPPH·的清除率在分心木黄酮浓度为0.07 mg/m L时即达到70.2%,并且具有很强的还原能力。     

菊苣酸抗氧化性及对抑制酪氨酸酶催化反应的动力学研究

以DPPH、·OH的清除效果和铁还原力为指标,采用酶动力学方法研究菊苣酸的抗氧化活性和对酪氨酸酶单酚酶和二酚酶的影响及抑制作用。结果表明:菊苣酸对DPPH、·OH自由基的清除率和铁还原力与菊苣酸浓度呈线性量效关系,IC_(50)值分别为13.63,14.26和13.78 mg/L。菊苣酸对酪氨酸酶单酚酶和二酚酶均具有较好的抑制作用,对单酚酶和二酚酶活性抑制的IC_(50)值分别为0.26 mmol/L和0.71 mmol/L,显著小于熊果苷对二酚酶活性抑制的IC_(50)值(5.3 mmol/L)。菊苣酸能明显延长单酚酶的迟滞时间。在浓度为0.40 mmol/L时,菊苣酸可使迟滞时间由134 s延长至383 s,延长2.87倍。Lineweaver-Burk菊苣酸对二酚酶的抑制表现为可逆竞争型抑制,最大反应速率(vm)为83.30μmol/L,抑制常数(KI)为0.14 mmol/L。     

白及多糖的超声-微波协同提取工艺及其抗氧化活性研究

目的:研究白及多糖的超声-微波协同提取工艺优化及其抗氧化活性。方法:以多糖得率为考察指标,通过单因素实验对料液比、浸泡时间、微波功率和协同提取时间4个影响因素进行考察,采用正交实验设计对超声波-微波协同提取白及多糖的工艺条件进行优化,并研究白及多糖对羟基自由基(·OH)、超氧阴离子(O_2~-·)和1,1-二苯基-2-苦肼基自由基(DPPH·)的清除率以评价其体外抗氧化活性。结果:最佳提取工艺条件为:液料比20∶1 m L/g,浸泡时间6 min,微波功率200 W,协同提取时间5 min,该工艺条件下多糖得率达6.98%±0.19%。单独超声波提取法和单独微波提取法的多糖得率仅为超声-微波协同提取法的46.28%和87.96%,表明超声-微波协同提取优于单独超声波提取和单独微波提取。抗氧化活性研究表明在实验范围内,白及多糖对O-2·无明显清除作用,但对·OH和DPPH·具有明显的清除作用,采用超声-微波协同提取法提取的白及多糖较微波提取法具有更高的·OH和DPPH·清除活性,当多糖浓度为0.5 mg/m L时,对·OH和DPPH·清除率分别为92.82%和74.21%。结论:超声-微波协同提取具有省时高效的特点,特别适用于多糖类物质的提取。     

蒲公英中菊苣酸的溶出特性及其抗氧化活性

菊苣酸是蒲公英的主要功效成分之一,为充分利用蒲公英资源,该文研究醇提过程中蒲公英菊苣酸随蒲公英粉末粒度、料液比、提取温度的溶出特性和抗氧化活性的变化。结果表明：蒲公英粉末粒度、料液比和提取温度不影响蒲公英菊苣酸的溶出特性,但影响蒲公英菊苣酸的溶出量、平均溶出速率。当提取时间小于60 min时,溶出量快速增加,平均溶出速率快速降低;当提取时间大于60 min时,溶出量缓慢增加,平均溶出速率缓慢降低。蒲公英菊苣酸的溶出量、平均溶出速率随蒲公英粉末粒度减小而增加,随提取温度升高而增加,随溶剂量增加而先增加后降低,蒲公英菊苣酸适宜的提取条件为蒲公英粉末粒度60目、料液比1∶30(g/mL)、提取温度80℃。菊苣酸是蒲公英醇提物中重要的抗氧化活性成分,具有较强的抗氧化能力,抗氧化结果表明,菊苣酸对DPPH·和ABTS⁺·的清除率随菊苣酸浓度增加呈线性增加,清除DPPH·的效果优于清除ABTS⁺·。     

辣木叶乙醇提取物的抗氧化活性研究

确定辣木叶中总抗氧化物质的最佳提取条件,并评价其体外抗氧化活性。在单因素试验结果的基础上,以DPPH自由基清除率为评价指标,通过采用正交试验研究乙醇体积分数、提取温度、料液比和提取时间4个因素对辣木叶抗氧化物质抗氧化活性的影响。结果表明:最佳提取条件为提取温度为90℃、料液比为1:30、乙醇体积分数为60%、提取时间为1.5 h,在此条件下,辣木叶中多酚含量为69.36±0.58 mg/g,黄酮含量为53.72±0.48 mg/g,DPPH自由基清除率为57.83±0.14%。辣木叶抗氧化物质粗提物对DPPH、ABTS和·OH自由基具有具有较好的清除效果,还原能力较弱,其EC50值分别为86、31和140μg/m L,对DPPH、ABTS和·OH自由基清除率分别达到相同质量浓度BHT的98.26%、99.04%和96.63%,并与辣木叶粗提物质量浓度存在一定的量效关系。     

负压超声法提取刺玫果黄酮及其抗氧化性研究

采用负压超声技术辅助乙醇提取刺玫果黄酮,在单因素试验基础上,以超声时间,超声温度,超声功率,料液比为影响因子,应用Box-Behnken中心组合进行四因素三水平试验设计,以刺玫果黄酮得率为响应值,响应面优化提取工艺,并测定了醇提物的铁还原力及DPPH·、OH·和O_2~-·的清除能力。确定最佳提取工艺为:料液比为1:30,超声功率为400 W,超声时间为33 min,超声温度56℃,在此条件下,黄酮得率为(3.342±0.027) mg/g,同时建立了乙醇溶液提取刺玫果黄酮的二次项数学模型,对目标产物的提取具有良好的预测作用。抗氧化试验表明:刺玫果黄酮有较好的还原性,对OH·、DPPH·和O_2~-·均有较好的清除能力,其IC50值分别为0.021 mg/mL、0.182μg/mL、0.013 mg/mL,还原力和对三种自由基的清除能力高于同浓度的Vc。说明负压超声法能够制备的刺玫果黄酮有较良好的抗氧化活性。     

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