苯酚-硫酸法测定银杏外种皮多糖的含量

目的:建立分光光度法测定银杏外种皮多糖的方法.方法:采用苯酚-硫酸法对银杏外种皮多糖含量进行测定,在单因素实验结果的基础上,进行正交实验设计,考察苯酚用量、硫酸用量和显色温度对吸光度的影响.结果:硫酸用量是影响显色的重要因素.最佳条件为5%苯酚1.2 mL、硫酸4 mL、显色温度30℃和显色时间20 min,该方法平均回收率为99.60%,RSD=3.02%(n=5).结论:该法快速.重现性好,适用于银杏外种皮多糖的含量测定.     

苯酚-硫酸法测定南瓜籽多糖含量的条件优化

对苯酚-硫酸法测定南瓜籽多糖含量的条件进行探讨,研究在苯酚-硫酸法中吸收波长、浓硫酸用量、苯酚用量、显色温度和显色时间等因素对显色结果的影响,并对该法的精密度、加标回收率等进行研究。结果表明,优化后的测定条件为显色波长486nm、6%苯酚的用量1.0mL、浓硫酸用量5.0mL、30℃水浴30min。该条件下,平均加样回收率为100.75%,相对标准偏差(RSD)为0.83%。证明苯酚-硫酸法是测定南瓜籽多糖含量的一种稳定性好、回收率高的简便方法。     

苯酚-硫酸法与蒽酮-硫酸法测定绿茶茶多糖的比较研究

对苯酚-硫酸法和蒽酮-硫酸法在茶多糖测定中的差异进行比较,并对苯酚-硫酸法的检测条件进行优化,在单因素试验的基础上,选定苯酚质量分数、硫酸用量、显色时间3 个因素,利用响应面试验考察各因素变化对吸光度的影响。通过优化得到最佳测定条件为4.8%苯酚溶液1 mL、浓硫酸5 mL、显色时间29 min、检测波长488 nm。在此条件下的标准曲线在0～0.2 mg/mL范围内呈良好线性关系。该方法对3 种样品的加标回收率均不小于97.55%,重复性实验相对标准偏差为1.82%,说明此方法准确可靠、稳定性高,适合于茶多糖的测定。     

扛板归多糖含量测定方法的建立

建立扛板归多糖的含量测定方法,效应面分析法研究扛板归多糖含量测定的最佳条件。以葡萄糖为标准品,采用苯酚-硫酸法和3,5-二硝基水杨酸法,分别测定扛板归水提液中总糖和还原糖的含量,从而计算多糖含量;在单因素试验的基础上,运用三因素五水平的星点设计-效应面分析法优选多糖测定的最佳条件。最佳测定条件如下,总糖:苯酚用量1.7 mL,硫酸用量8.7 mL,显色时间11 min;还原糖:显色剂用量2.7 mL,显色时间10 min,显色温度81 ℃。在最佳测定条件下,总糖和还原糖的样品加标回收率分别为102.26%(RSD=4.03%,n=9)和102.89%(RSD=2.66%,n=9)。扛板归多糖含量为46.72 mg/g。本方法灵敏、稳定、重复性好,可用于扛板归多糖含量的测定。     

苯酚-硫酸法测定瓦尼木层孔菌菌丝体多糖含量的条件优化

对瓦尼木层孔菌菌丝体多糖含量的测定进行了探讨,研究了在苯酚-硫酸法中吸收波长、显色温度、显色时间、浓硫酸用量、苯酚用量等因素对显色结果的影响。通过实验发现,最佳显色条件是波长492nm、显色温度100℃、显色时间20min、浓硫酸用量4.5mL、苯酚用量0.4mL,平均加样回收率100.7%,相对标准偏差(RSD)为0.67%。     

苯酚-硫酸法与蒽酮-硫酸法测定地参多糖的比较研究

苯酚-硫酸法和蒽酮-硫酸法是测定多糖含量的常用方法,运用这2种方法测定地参中多糖的含量,比较2种方法的优劣,发现苯酚-硫酸法较优,并对苯酚-硫酸法做更深入的优化试验。在单因素试验结果的基础上,选取苯酚用量、硫酸用量、加热时间3个因素进行响应面优化试验,得出最佳试验条件为苯酚用量0.8 mL、硫酸用量3.5 mL、加热时间9 min。利用该条件对地参多糖进行测定,得出地参多糖含量的平均值为14.41%,相对标准偏差为2.76%,表明苯酚-硫酸法稳定可靠,更能准确测定地参中多糖的含量。     

苯酚-硫酸法测定油菜花粉多糖含量的研究

以葡萄糖为对照,优选苯酚-硫酸法测定油菜花粉多糖含量的显色条件,对该法稳定性、精密度、是否受蛋白质干扰等方面进行了研究,得出最佳显色方式为:取待测油菜花粉多糖2mL,加入浓度为5%苯酚1mL,迅速滴加浓硫酸5.0mL,摇匀后于室温放置20min,在482nm处测定吸光度。结果表明,此测定方法简便灵敏,显色稳定,不受蛋白质干扰。     

苯酚-硫酸法测定海湾扇贝多糖方法的研究

以葡萄糖为标准品,优化苯酚-硫酸法测定海湾扇贝多糖含量的条件,并对该法的精密度、加标回收率等进行了研究,得出最佳显色条件为：苯酚用量1．0mL,浓硫酸用量5．0mL,室温放置30min,在480nm处测定吸光度。结果表明．此方法是测定海湾扇贝多糖含量的一种稳定性好、回收率高的简便方法。     

苯酚-硫酸法测定酒蒸多花黄精多糖含量的优化

目的:建立苯酚-硫酸法测定酒蒸多花黄精中多糖含量的最优方法。方法:同时采用蒽酮-硫酸法、苯酚-硫酸法对酒蒸多花黄精的多糖含量进行测定,针对苯酚-硫酸法选取苯酚浓度、苯酚用量、硫酸用量、加热时间、加热温度进行单因素考察、利用响应面法进行分析、优化。结果:利用响应面进行F值分析,各因素对吸光度的影响大小为:硫酸用量>苯酚浓度>苯酚用量,加热温度及时间无明显影响。得到最佳工艺为苯酚用量1.5 mL、苯酚浓度4.5%、硫酸用量6.5 mL。对酒蒸多花黄精多糖进行测定,平均含量为8.50%,相对标准偏差为0.87%。结论:苯酚-硫酸法进一步优化后得到的方法能够准确测量酒蒸多花黄精中的多糖含量,为进行质量标准深入研究提供了参考价值。     

玛咖多糖含量的测定

用水提醇沉法从玛咖块根粉末中提取了玛咖多糖,Sevage法脱蛋白。玛咖多糖含量用硫酸-苯酚法测定,测定波长为490nm,正交试验设计选择得到玛咖多糖的最佳显色条件。在10￣60μg/mL范围内吸光度与被测物含量呈良好的线性关系,r=0.9998。测得多糖含量为2.55%,精密度为0.52%。结果表明该方法准确度好、灵敏度高。     

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