响应面法优化固相酸水解鲍鱼脏器多糖工艺

为了研究鲍鱼脏器多糖固相酸(732#阳离子交换树脂)水解条件与多糖水解率之间的关系及其降解产物的分子结构,首先通过单因素实验确定树脂用量、水解时间和水解温度对鲍鱼脏器多糖水解率的影响,然后应用响应面法对鲍鱼脏器多糖水解条件进行设计优化,最后采用 Sephadex G-25 凝胶柱对鲍鱼脏器寡糖混合物进行分离纯化,并使用红外光谱分析对寡糖结构进行测定。结果表明:对多糖水解率的影响程度依次是水解温度、水解时间和树脂用量,最佳水解条件为:树脂用量40 g,水解时间3 h,水解温度70 ℃。在此条件下进行3次平行验证试验,鲍鱼脏器多糖水解率为80.69%,接近且略高于预测值,表明应用响应面法优化鲍鱼脏器多糖的水解条件是可行的。凝胶层析法纯化结果表明,鲍鱼脏器寡糖混合物中有两个组分,且第1组分占大多数。红外光谱分析表明,鲍鱼脏器寡糖为α-型糖,含有吡喃环。鲍鱼脏器多糖固相酸水解工艺研究,提高了鲍鱼脏器加工的经济效益,为鲍鱼脏器的高值化利用提供了参考。     

木瓜蛋白酶水解豌豆蛋白的工艺研究

研究木瓜蛋白酶对豌豆蛋白的水解作用,分析了酶量、底物浓度、温度、pH、水解时间因素对水解度的影响,确定木瓜蛋白酶水解豌豆蛋白制备豌豆多肽的最佳水解条件为:酶浓度8%(E/S质量比),底物浓度7%(固液比).反应温度65℃,反应时间3.5 h,pH6.5,并利用高效液相色谱法测定豌豆多肽分子量.试验结果表明,当水解度为30%时,豌豆多肽混合物分子量80%集中在500u左右.     

凝胶渗透色谱法研究裂褶多糖酶降解过程中的分子量及其分布

采用凝胶渗透色谱法检测反应温度、反应时间和酶液饱和度对裂褶多糖在酶解过程中的分子量及分子量分布的影响.结果表明,内切β-1,3-葡聚糖酶降解裂褶多糖可采用饱和度 80%的酶液,最适反应温度为 50℃,反应时间控制在2 h以内能得到较好的降解效果.利用凝胶渗透色谱法可以有效监控裂褶多糖降解反应程度.     

黑木耳多糖的降解及其产物抗氧化性

采用水提醇沉法提取黑木耳多糖（Auricularia auricula polysaccharide,AAP）,用三氟乙酸（trifluoroacetic acid,TFA）降解黑木耳多糖,经单因素和响应面试验优化降解条件;纯化后多糖采用高效凝胶渗透色谱、红外光谱、高效液相色谱测定多糖分子量、红外谱图及单糖组成并测定多糖的体外抗氧化活性。结果表明：TFA浓度为0.8 mol/L、温度为78.2℃、降解2.1 h,降解黑木耳多糖的DPPH自由基清除率为70.37%。降解后黑木耳多糖分子量由148.2 kDa变为37.5 kDa,特征官能团结构及单糖组成无明显变化,为分子修饰黑木耳多糖提供试验基础。     

葱白多糖的分离纯化及分子量分布研究

研究了葱白多糖的分离纯化以及分子量分布。试验结果表明:经沸水提取、脱除果胶、透析后的葱白多糖含量为75.0%。采用Sephadex G-150柱层析纯化,得到葱白多糖P2。经过紫外扫描和高效液相色谱法分析表明:P2为均一多糖,高效液相凝胶色谱法测定P2分子量(Mw)为5.195kDa。     

鲍鱼脏器多糖提取条件的研究

以多糖得率为指标,研究了六种蛋白酶酶解鲍鱼脏器获得多糖的效果,结果表明碱性蛋白酶为最佳用酶,并对其工艺中温度、pH、水解时间等影响因素进行了实验分析,确定最适条件为:温度45℃,底物浓度2.5%,pil10.0,加酶量2.0%,水解时间3h,在此条件下,鲍鱼脏器多糖得率为6.50%.     

浒苔多糖的磷酸化修饰工艺

利用离子交换层析和凝胶层析对浒苔多糖进行分离纯化,并探讨其磷酸化修饰的最佳工艺条件。通过单因素试验确定反应温度、反应时间、反应pH值、磷酸化试剂质量浓度的取值范围,再用响应面设计法确定磷酸化修饰的最佳条件。结果表明:反应时间、磷酸化试剂质量浓度显著影响浒苔多糖磷酸化程度,当反应温度80℃、反应时间5h、反应pH9.0、磷酸化试剂质量浓度0.10g/mL时,磷酸化修饰的浒苔多糖磷酸根含量(以P计)达到14.40%。     

橘皮多糖微波提取工艺优化及分离纯化研究

利用响应面法优化微波辅助提取橘皮多糖工艺。在单因素实验的基础上,选择3因素3水平的Box-Behnken Design(BBD)实验设计考察微波功率、提取温度和提取时间对多糖提取得率的影响。得到最佳提取条件为:微波功率704 W、提取温度52℃、提取时间41 min。在此条件下橘皮粗多糖的提取得率为(19.86±0.23)%,与预测得率基本一致。粗多糖用纤维素DEAE-52和葡聚糖G-75凝胶进行了分离纯化,得到主要纯化多糖组分的平均分子量和纯度用高效凝胶渗透色谱法(HPGPC)进行了测定。分离纯化得到的主要多糖组分(TPPs-Ⅱ)为平均分子量17.81 ku的均一多糖组分。说明响应面优化得到的微波辅助提取工艺参数准确、可靠。     

燕麦多糖的提取工艺及分子量分布研究

通过单因素实验和正交实验研究了燕麦多糖的提取条件,并采用Sephadex G-75色谱柱对燕麦多糖进行了纯化,采用高效液相色谱法测定了燕麦多糖的分子量分布。结果表明,燕麦多糖的最佳提取条件为:提取温度60℃,料液比1∶10,提取时间1.5h,提取3次,该条件下燕麦多糖得率为10.92±0.03g/100g。高效液相色谱测定结果表明,燕麦多糖是由分子量为400～600kDa和150kDa两部分组成的。     

H_2O_2/HAc氧化降解壳聚糖的探讨

采用过氧化氢-醋酸氧化降解法,探讨冰醋酸用量、反应温度、过氧化氢用量和反应时间对降解壳聚糖分子量的影响。     

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