D301-G大孔树脂吸附菊芋多糖色素机理探究

为了探究菊芋多糖提取液中色素杂质的去除效果,本文采用静态吸附法对六种大孔树脂进行了初步筛选,并研究了D301-G大孔树脂对菊芋多糖色素的静态吸附动力学、静态吸附模型及其吸附热力学,深入探讨了D301-G大孔树脂对菊芋多糖色素的吸附机理。结果表明,在相同的实验条件下,D301-G大孔树脂与其它树脂相比脱色效果最好,吸附菊芋多糖色素速率较快,多糖的损失率最小,脱色率可达到79.63%,多糖保留率为92.28%。此外D301-G大孔树脂对菊芋多糖色素的吸附过程符合准二级吸附动力学方程,主要受颗粒扩散阻力的影响。等温吸附实验表明,在293、303和313 K时Freundlich等温线模型较Langmuir模型更为准确地描述D301-G大孔树脂的吸附行为,它对色素分子的吸附可能是多分子层的。热力学方程表明D301-G大孔树脂吸附过程是一个吸热过程,吸附焓变ΔH 0、吸附自由能变ΔG 0、吸附熵变ΔS 0。     

D201大孔吸附树脂对料酒中蛋白质的吸附平衡及热力学与动力学研究

采用静态吸附方法,研究了料酒中蛋白质在D201大孔吸附树脂上的吸附等温曲线以及吸附热力学与动力学.结果表明,料酒中蛋白质在D201大孔吸附树脂上的吸附符合Langmuir模型(R2>0.98),蛋白质在树脂上的吸附为吸热过程,其传质速率随温度的升高而增加,最大吸附量为112.26 mg/g;热力学研究结果表明,整个吸附...     

大孔树脂吸附桦褐孔菌多糖色素的机理及工艺优化

为探究大孔树脂吸附桦褐孔菌多糖色素动力学与热力学特征及最佳工艺条件,本实验通过水提醇沉、Sevag法除蛋白、透析制备桦褐孔菌多糖,采用静态吸附实验筛选色素吸附率及多糖保留率评分最高的大孔树脂,研究其吸附动力学与热力学特性,并优化该大孔树脂在动态吸附桦褐孔菌多糖色素中的径高比、吸附时间、上样量以及洗脱流速,确定最佳工艺条件。结果表明,实验筛选的17个不同型号大孔树脂中,大孔树脂HPD-500最为适宜,其吸附色素的过程符合准二级动力学模型,反应过程中受颗粒内扩散与液膜扩散的影响;并且吸附过程符合热力学Freundlich模型,为多分子层吸附,其中吸附焓变>0为吸热反应,吉布斯自由能<0为自发反应,吸附熵变>0为熵增反应。HPD-500吸附色素的最佳条件为径高比1:10,吸附时间1 h,上样量10 mg,洗脱流速1.5 mL/min。在此条件下,桦褐孔菌的色素吸附率为83.15%,多糖保留率为78.89%,多糖纯度由20.40%提升至56.52%。HPD-500大孔树脂具有吸附桦褐孔菌多糖中色素、提高多糖纯度的能力,本文为桦褐孔菌资源高效利用提供了理论及实验基础。     

离子交换法提取发酵液中乳酸的工艺研究

选用弱阴离子树脂D301G 和D311 从发酵液中提取乳酸,研究过程中对时间、温度、发酵液浓度、转速、pH 值、流速和树脂填充量等影响因素加以系统考察。通过单级工艺研究确定最佳操作条件为：时间3h、发酵液浓度86.0g/L、pH3,此条件下的交换容量为237mg/g。另外对特定树脂吸附乳酸的动力学和热力学也进行了研究,得到了D301G 的等温吸附曲线,符合Freundish 吸附等温方程,方程为Qc=KC1/n,其吸附过程的动力学方程为Qt=Q0+aet/b。     

黑果枸杞多酚吸附分离特性及抗氧化性研究

采用静态吸附法对9种大孔树脂进行了初步筛选,研究了HPD500大孔树脂对黑果枸杞多酚的静态吸附动力学、热力学特性,深入探讨了HPD500大孔树脂对黑果枸杞多酚的吸附机理、动态纯化工艺,评价了其抗氧化活性。HPD500树脂纯化黑果枸杞多酚较为理想,吸附过程符合准二级吸附动力学方程,主要受化学反应模型控制。Langmuir方程在考察温度范围内能很好地描述HPD500大孔树脂对黑果枸杞多酚的吸附热力学行为,ΔH<0、ΔG<0、ΔS<0说明吸附过程自发放热且熵减。HPD500大孔树脂动态纯化黑果枸杞多酚较佳的工艺条件为:将0.8 mg/mL的黑果枸杞粗提液以2.4 BV/h流速上样8 BV量,60%(体积分数)的乙醇溶液以2.4 BV/h流速洗脱,用量6 BV,总多酚纯度较纯化前提高2.36倍。抗氧化活性实验表明,黑果枸杞多酚有较强的羟自由基和超氧阴离子自由基清除能力,IC 50分别为1.3090、0.0708 mg/mL。该研究为黑果枸杞进一步开发利用、拉长其产业链提供依据。     

HZ816大孔树脂对番茄红素的吸附特性研究

利用大孔吸附树脂HZ816对番茄红素进行吸附实验,研究吸附过程的动力学及热力学特性,并对吸附过程的速率控制模型进行模拟. 结果表明,HZ816大孔吸附树脂对番茄红素的吸附过程符合Lagergren一级吸附动力学方程及Kannan颗粒内扩散方程,吸附过程受液膜扩散阻力及颗粒内扩散阻力的共同影响. 其等温吸附规律符合Freundlich等温方程,热力学参数吸附焓变AH<0、吸附自由能变AG<0、吸附熵变△S>0,表明番茄红素在HZ816吸附树脂上的吸附为熵驱动的放热、熵增的自发过程,属于物理吸附范畴.     

大孔树脂对花生壳总黄酮的吸附热力学研究

通过静态吸附实验,选择AB-8型大孔树脂对花生壳总黄酮进行吸附,研究了吸附过程中的热力学特性。采用Freundlich、Langmuir和Temkin 3种常用的吸附等温方程拟合形成吸附等温线方程,在此基础上利用热力学函数计算吸附过程中的吸附焓变ΔH、熵变ΔS和自由能变ΔG。结果表明:该吸附是一个物理过程;Freundlich吸附等温线模型能可靠地反映吸附过程,20、25、30、35、40℃5个温度下的特征参数n值都大于1,表明吸附是优惠吸附;吸附过程中焓变ΔH大于0且与温度无关、熵变ΔS大于0和自由能变ΔG小于0,表明吸附是由熵推动的自发的吸热过程。     

改性磁性壳聚糖对胭脂红的吸附性能评价

以纳米Fe₃O₄、壳聚糖为材料,采用反相悬浮交联法,用三乙胺做改性剂制备改性磁性壳聚糖,研究其对胭脂红色素的吸附性能影响,考察时间、pH、温度及胭脂红的初始浓度等四个因素对改性磁性壳聚糖吸附胭脂红溶液吸附效果的影响,并对吸附动力学模型、吸附等温模型、吸附热力学和吸附再生性能进行初步探讨。结果表明,当pH=3,吸附时间为270 min,温度为50℃,初始浓度为100 mg/L时,改性磁性壳聚糖对胭脂红溶液的吸附率达到最高,为96.72%。改性磁性壳聚糖对胭脂红溶液的吸附动力学数据符合准二级动力学模型,吸附等温线数据符合Langmuir模型,热力学数据拟合得出ΔH>0,ΔS>0,ΔG<0,得出此反应是吸热反应。经过三次吸附-解析实验,吸附率和解析率仍在40%以上。     

离子交换树脂对冰葡萄汁总酸和总酚的静态吸附动力学研究

该实验研究了D354树脂对冰葡萄汁总酸和总酚的静态吸附动力学模型。结果表明,随吸附温度的升高,D354树脂对冰葡萄 汁总酸和总酚的吸附速率显著提高（P＜0.05）。 在0 ℃、10 ℃和20 ℃条件下,D354树脂对冰葡萄汁总酸的最大吸附量分别为151.69 mg/g、 190.09 mg/g及222.16 mg/g;对冰葡萄汁总酚的最大吸附量分别为3.65 mg/g、4.20 mg/g及4.67 mg/g;D354树脂吸附冰葡萄汁总酸和总 酚的过程符合拟二阶动力学模型（R2＞0.9980）,并确定了D354树脂对冰葡萄汁总酸和总酚的拟二阶动力学方程;利用W-M（Weber- Morris）动力学模型对数据拟合（R2＞0.9300）,结果表明整个静态吸附过程受粒内扩散和液膜扩散共同控制。     

刺梨多酚的纯化工艺及体外抗氧化研究

以刺梨全果为原料,探讨刺梨多酚的纯化工艺,并分析其抗氧化作用。比较AB-8、D101、D301、HPD100、HPD300和LSA-10六种不同型号的大孔树脂对刺梨多酚的吸附及解吸效果,筛选最佳大孔吸附树脂;在三个实验温度下探讨AB-8型对刺梨多酚的静态吸附热力学特性,通过研究初始pH、吸附时间、解吸液浓度、上样量及洗脱液用量等多个因素优化刺梨多酚的纯化参数,并进一步研究其抗氧化活性。结果表明,AB-8型大孔树脂更适于刺梨多酚的吸附,其吸附过程符合Freundlich热力学模型(R²>0.990 0)及Langmuir模型(R²>0.950 0),当实验温度为298 K时更利于大孔树脂对刺梨多酚的吸附;其较适纯化参数为：吸附时间600 min、解吸溶剂80%乙醇溶液、上样量10 mL、洗脱液用量50 mL。在该纯化工艺参数下,刺梨多酚的平均含量从30.45%增加至56.92%。抗氧化实验表明,刺梨多酚有较好的抗氧化能力,粗提液和纯化液对DPPH·及ABTS⁺·的清除能力都存在显著差异,在同一浓度下纯化后的刺梨...     

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