微波辅助元蘑子实体多糖提取工艺优化及抗氧化活性研究

为优化微波辅助元蘑子实体多糖的提取工艺条件，并研究其抗氧化活性，以元蘑子实体为研究对象，在单因素试验的基础上，采用Box-Behnken响应面试验法对元蘑子实体多糖的微波辅助提取工艺条件进行优化，并通过测定元蘑子实体多糖对羟基自由基、DPPH自由基、超氧阴离子自由基的清除能力和对铁离子的还原能力来评价其抗氧化活性。结果表明：元蘑子实体多糖的最佳微波辅助提取工艺为微波时间257 s、微波功率500 W、液料比61:1(mL/g)，在此条件下，元蘑子实体多糖提取量为32.36 mg/g(n=3,RSD=0.84%)。元蘑子实体多糖浓度为1.4mg/mL时，对铁离子具有较强的还原能力，对羟基自由基的清除率为88.27%，对DPPH自由基的清除率为87.09%，对超氧阴离子自由基的清除率为82.73%,IC₅₀值分别为0.74、0.61 mg/mL和0.81 mg/mL。     

5种灵芝孢子粉多糖含量的分析对比研究

采用超声波辅助热水法提取灵芝孢子粉多糖,结粜表明该方法精密度良好,超声处理时间为25min,处理温度为70℃.多糖含量采用传统的苯酚-硫酸法榆测.实验结果表明,3号灵芝孢子粉样品中多糖含量高,并且所含灵芝多糖稳定性好.     

真菌保健食品中多糖含量测定方法的比较

采用不同的测定方法测定真菌保健食品中的粗多糖的含量,考察标准品、提取方法、醇沉时间及显色方法等因素对多糖测定结果的影响。实验表明选用硫酸苯酚法进行显色,葡萄糖做标准品,超声功率250W,超声提取30min,醇沉10min,测定结果较好。该方法精密度、稳定性好,平均加样回收率高,方法简单,快速,准确,可用于真菌保健食品各种粗多糖的测定和质量控制。     

高效毛细管电泳法测定羊肚菌(Morchella sextelata)菌丝中单核苷类化合物含量的研究

建立了羊肚菌Morchella sextelata菌丝中单核苷类化合物的含量高效毛细管电泳测定方法。确定采用菌粉按照1∶30加水先超声后水浴的方法提取样品,最佳电泳条件为pH为9.4的50 mmol/L硼砂缓冲液以及1.0 mg/mL的β-环糊精为运行缓冲液,分离电压为25 kV,进样时间为8 s。在最佳电泳条件下,5种标准品在20 min内得到了分离,精密度试验中同一批次三次进样的标准品混合物迁移时间RSD均小于0.89%,峰面积RSD均小于2.9%;在稳定性试验中,5种标准品在8 h内迁移时间RSD均小于0.61%,峰面积RSD均小于4.73%。表明标准品在8 h内具有良好的稳定性。结果表明:该方法能够测定出羊肚菌中含有3-脱氧腺苷、腺苷和尿苷。通过建立标准曲线测得羊肚菌菌丝中3-脱氧腺苷含量为4.38 mg/g,腺苷含量为6.6 mg/g,尿苷含量为7.8 mg/g。3种单核苷类化合物的回收率在95.5~100.8%之间,且RSD小于4.9%(n=3)。表明该方法适用于羊肚菌Morchella sextelata菌丝中的单核苷类化合物的测定。     

蜂花粉多糖和黄酮的联合提取及含量测定

以蜂花粉为原料,用石油醚回流脱去脂类和色素,再用80%乙醇80℃回流2次提取蜂花粉黄酮;滤渣用80℃水提3次后,醇沉后,并用sevag法脱蛋白。计算多糖和黄酮的提取率和纯度,并对试验方法的重复性、精密度和稳定性进行考查。蜂花粉中黄酮的提取率为2.56%(RSD=1.722%,n=5),纯度为82.3%(RSD=2.517%,n=5),多糖提取率为3.11%(RSD=2.826%,n=5),纯度为91.6%(RSD=1.992%,n=5);精密度试验RSD_(黄酮)=1.760%,RSD_(多糖)=1.507%,稳定性试验中显色后的90 min内稳定性较好,RSD_(黄酮)=2.947%,RSD_(多糖)=2.632%。     

白灵菇菌丝体多糖两种测定方法的比较

为选出一种比较准确、方便的测定食用菌菌丝体多糖方法,以白灵菇菌丝体提取的粗多糖为原料,对苯酚-硫酸法、蒽酮-比色法2种方法进行比较。苯酚-硫酸法和蒽酮-硫酸法的稳定性实验RSD分别为0.71%和1.40%,精密度实验RSD分别为2.10%和9.53%,回收率平均值分别125.41%和154.88%;苯酚-硫酸法具有稳定性好、精密度高,而且回收率实验也较为理想,是测定食用菌菌丝体多糖含量较为理想的方法。     

高效凝胶渗透色谱法检测菊糖相对分子质量

为了建立利用高效凝胶渗透色谱测定菊糖相对分子质量的方法,采用GPC 色谱柱,示差折光检测器检测,以三蒸水为流动相,流速0.8ml/min,柱温30℃。结果表明不同分子量标准右旋糖酐的保留时间与相应的相对分子质量对数值(lgMw)在相对分子质量1.0 × 103～2.5 × 104 范围内具有良好的线性关系(r= 0.9894),精密度实验RSD 为0.24%,重现性实验RSD 为0.21%,稳定性实验RSD 为0.38%,准确度实验相对误差在0.4% 左右。该法简便、快速、灵敏度高,精密度、重现性及稳定性均较好。用此法检测热回流、超声、微波三种提取工艺得到的菊糖相对分子质量分别为：热回流提取3500,超声提取2405,微波提取3864。     

黑果枸杞叶片中多糖提取工艺研究

采用水浴法、微波辅助提取法与超声一微波协同萃取法提取黑果枸杞叶片多糖,确定最适提取方法.通过单因素试验和正交试验确定最优提取工艺.采用蒽酮一硫酸法测定多糖含量.结果表明:最佳提取方法为超声一微波协同萃取法.最优提取条件是:料液比为1:25,提取温度为90℃,提取时间为30 min,多糖平均提取率为10.07%,RSD:1.60%(n=3).回收率100.7%,RSD=1.84%(n=3).     

柚寄生多糖的提取与含量的测定

建立一种简便可靠的柚寄生多糖的含量测定方法。采用水提醇沉法提取柚寄生多糖,以葡萄糖为对照品,采用蒽酮硫酸法测定柚寄生多糖的含量,用精制柚寄生多糖测得柚寄生多糖对葡萄糖的换算因子,对该含量测定方法的精密度、稳定性、重现性和加样回收率均进行了考察。该方法的精密度、稳定性、重现性和加样回收率结果均良好,测得柚寄生多糖的含量为3.55%。     

人参果多糖超声提取工艺的研究

研究人参果多糖超声波辅助提取的最佳工艺.通过单因素及正交试验进行超声辅助提取人参果多糖;采用葱酮-硫酸法测定人参果多糖的含量.超声波辅助提取人参果多糖的最佳工艺条件为:料液比1:30,作用时阃15min,超声波温度40℃.采用超声波辅助提取人参果多糖的平均提取率(干重)为14.986(mg/g),精密度好,RSD(n=5)为2.21%.     

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