椰子皮多糖的提取、结构表征及生物活性研究

以椰子皮为原料，在单因素试验的基础上，采用沸水浸提法优化椰子皮多糖的提取工艺。同时对椰子皮多糖进行紫外光谱、红外光谱、13C NMR和DEPT 135分析，并利用清除ABTS+自由基、DPPH自由基和O₂^-能力评价其体外抗氧化活性，同时也评价了体外抗HepG2增殖活性。结果表明，椰子皮多糖的最佳提取工艺条件为：浸提温度100℃，浸提时间3小时，料液比1∶5(w/w)，在此条件下椰子皮多糖提取率为4.73%。体外抗氧化试验表明，椰子皮多糖对ABTS+自由基、DPPH自由基和O₂^-均有一定的清除效果，随着椰子皮多糖浓度的增加清除能力逐渐增强，当多糖浓度为3.2 mg/mL时，其对ABTS+自由基、DPPH自由基和O₂^-的清除率分别达到89.58%、94.62%和95.21%，此时抗氧化能力与维生素C相当。与此同时，体外抗细胞增殖试验表明，椰子皮多糖对HepG2细胞显示出明显的抗增殖活性。     

红蓝草多糖提取工艺优化及其抗氧化活性分析

为探究红蓝草多糖的最佳提取工艺及其体外抗氧化活性。试验以红蓝草为原料,探究料液比、浸提温度、浸提时间、浸提次数对红蓝草多糖得率的影响,并结合响应面法优化红蓝草多糖提取工艺,通过测定红蓝草多糖对DPPH·、·OH、ABTS+·等自由基的清除能力探究其抗氧化活性。结果表明:在料液比1:31 g/mL、浸提温度85 ℃、浸提时间118 min、提取3次的条件下,红蓝草多糖得率最高,可达11.05%。在一定范围内,红蓝草多糖清除自由基能力与多糖的浓度呈量效关系,红蓝草多糖溶液清除DPPH · 、 · OH和ABTS + ·等自由基的IC₅₀值分别为0.18、0.73、0.64 mg/mL,说明红蓝草粗多糖具有一定的抗氧化活性。通过探究红蓝草多糖提取的最佳工艺及抗氧化活性,为今后红蓝草多糖的进一步开发与应用提供理论基础和参考。     

超声波辅助提取玉木耳多糖及其抗氧化活性分析

以玉木耳为原料,考察液料比、超声功率、超声温度和超声时间对多糖得率的影响,在单因素试验基础上,通过响应面分析法优化提取工艺条件,采用傅里叶红外光谱(FT-IR)对多糖结构进行初步表征,并通过测定玉木耳多糖清除1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基能力、铁离子还原能力(FRAP 法)和氧自由基清除能力(ORAC 法)研究其体外抗氧化活性。结果表明,超声波辅助法提取玉木耳多糖最优工艺为:液料比40∶1 mL/g,超声功率210 W,超声温度62 ℃,超声时间29 min,此工艺条件下玉木耳多糖的得率为7.43%;玉木耳多糖显示出多糖的典型特征吸收峰,是以β-糖苷键为主的吡喃型多糖;玉木耳多糖清除DPPH自由基IC₅₀值为1.445 mg/mL,FRAP值和ORAC值分别为35.14±0.16 mmol Trolox g-1和0.627 mg Trolox mg-1,具有较好的抗氧化能力,可作为天然抗氧化剂应用。     

响应面法优化提取珍珠花抗氧化总黄酮及其成分分析

以珍珠花为原料,采用单因素结合响应面法优化珍珠花抗氧化活性总黄酮超声辅助乙醇提取工艺,分别采用ABTS法、DPPH法和FRAP法评价总黄酮体外抗氧化能力,运用超高效液相色谱/四极杆-飞行时间质谱鉴定珍珠花抗氧化活性总黄酮化学成分并测定主要化合物含量。结果表明：珍珠花抗氧化活性总黄酮最佳提取工艺为乙醇体积分数70%、液料比40:1、提取时间120 min、超声时间30 min,总黄酮含量(65.23±0.06)mg RT/g DW;ABTS⁺自由基清除能力TE当量值为(0.16±0.01)mmol TE/g,清除DPPH自由基IC₅₀值为(72.00±2.00)μg/m L,铁离子还原能力(0.37±0.02)mmol Fe²⁺/g。从提取物中鉴定到5种化合物,分别是咖啡酸、芥子酸、金丝桃苷、异槲皮苷、紫云英苷,其中紫云英苷含量为(507.55±0.04)μg/g DW。     

铁皮石斛多糖复合酶法提取工艺及其抗氧化性

探讨复合酶法提取铁皮石斛多糖的最佳工艺以及酶解多糖的抗氧化活性。利用单因素及L₁₈(37)正交实验研究了酶配比、酶浓度、酶解温度、酶解时间、料液比及pH对多糖得率的影响,并通过清除DPPH、ABTS自由基研究酶解多糖的抗氧化活性。结果显示酶解最优条件:中性蛋白酶与纤维素酶比例为2:1,酶浓度为10%,料液比为1:120,酶解温度为55 ℃,pH6.0,酶解时间为3 h,在此条件下多糖得率为43.85%±1.8%;酶解多糖对DPPH、ABTS自由基的IC₅₀分别为1.331、0.467 mg/mL,说明酶解石斛多糖具有较好的抗氧化活性。     

微波-超声波协同辅助优化阳荷多糖提取工艺及抗氧化性分析

以野生阳荷为原料,采用微波-超声协同辅助提取阳荷中的多糖并优化其提取工艺,借助体外抗氧化模型对阳荷多糖进行抗氧化分析。响应面分析法优化得到阳荷多糖的最优提取工艺为:超声功率454 W,提取时间15 min,提取温度67℃,料液比1∶26(g/mL)。在此工艺条件下,阳荷多糖的最优得率为(10.40±0.35)%。体外抗氧化活性分析表明,阳荷多糖具有较强的清除DPPH·、ABTS+·、超氧阴离子自由基(O2-·)和羟基自由基(·OH)能力,其自由基清除活性随阳荷多糖浓度的增加而增强,证明阳荷多糖是一类优异的自由基清除剂。     

玉米须多糖酸提取工艺及其抗氧化活性的研究

采用正交试验优化玉米须多糖酸提取的最优工艺,通过测定多糖的1,1-二苯基-2-三硝基苯肼(DPPH)自由基和2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)二铵盐(ABTS)自由基清除能力来评估酸提取和水提取多糖的抗氧化活性,并通过红外光谱法比较2种多糖的差异。结果表明,酸提取最优工艺条件为温度90℃、盐酸浓度0.26 mol/L、料液比1∶50(g/mL)、提取2次、每次提取80 min。在此条件下,酸提取多糖(AEP)和水提取多糖(WEP)的得率分别为33.36%和7.44%,但AEP的抗氧化活性比WEP的弱。结合红外光谱法(IR)分析,得出AEP的结构或者组成有所改变。     

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。     

黔产皂角米多糖提取动力学及抗氧化活性研究

目的:以皂角米为原料,研究皂角米多糖的提取动力学及其抗氧化活性.方法:以Fick第一定律为基础,建立皂角米多糖的提取动力学模型,采用红外光谱对皂角米多糖进行结构分析,通过测定皂角米多糖对ABTS自由基、羟基自由基、1,1-二苯基-2-三硝基苯肼(DPPH)自由基、超氧阴离子自由基的清除能力来评价其抗氧化活性.结果:建立...     

金花葵多糖提取工艺优化及结构表征和抗氧化性研究

优化金花葵干花苞中多糖的提取工艺,并对其结构和抗氧化活性进行研究。本研究在单因素实验的基础上,通过正交试验优化水提醇沉法提取多糖的工艺,利用高效液相色谱(HPLC)法分析多糖的单糖组成,应用傅里叶红外光谱(FTIR)法和扫描电镜(SEM)观察对多糖官能团和外貌进行分析,并检测了多糖清除自由基的能力和还原力。结果表明,金花葵的干花苞多糖最佳提取工艺为：提取温度100℃、提取时间3 h和料液比1:50 g/mL。在此工艺条件下,多糖得率为17.23%±0.19%,多糖含量为27.87%±0.60%。其单糖组成及摩尔比为阿拉伯糖:半乳糖:鼠李糖:甘露糖:葡萄糖=0.97:1:0.23:0.05:0.43。表面呈不规则片状,并且证明具有糖醛酸、吡喃糖环官能团。此外,提取的多糖具有一定的清除DPPH自由基、ABTS⁺自由基能力,对自由基半数抑制对应浓度(IC₅₀)分别为1.22、4.43 mg/mL,表明具有良好的抗氧化活性。研究结果为金花葵花苞中多糖的化学结构解析和功能研究提供了研究基础与理论依据。     

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