石耳多糖的提取工艺研究

采用单因素试验和正交试验设计,探讨提取时间、料液比和提取温度对石耳多糖提取率的影响,筛选出了最佳提取工艺。结果表明,影响石耳多糖提取率的主次因素为料液比、提取温度及提取时间;石耳多糖最佳提取工艺条件为:提取温度80℃,提取时间4h,料液比1∶10。在此工艺条件下,水溶性石耳多糖的提取率为4.63%。     

2种石耳中多糖的提取及含量测定

从淡肤根石耳和网脊石耳提取了多糖,并应用分光光度法进行多糖含量测定.经蒽酮-硫酸显色,波长615nm处测定其多糖含量分别为网脊石耳为13.71%,淡肤根石耳为11.52%,研究结果表明蒽酮硫酸法简便,样品溶液显色稳定,重复性好,仪器精密度良好,平均回收率分别为网脊石耳为98.35%,RSD=1.35% (n=3),淡肤根石耳为99.32%,RSD= 1.97% (n=3).     

两种石耳中多糖的提取与分离纯化及其单糖组成分析

目的:对网脊石耳(Umbilicaria decussate(Vill.)Zahlbr.)和淡肤根石耳(Umbilicaria virginis Schaer.)多糖中的单糖组成进行研究。方法:两种石耳经水提、醇沉、冷冻干燥得水溶性多糖,经DEAE-52离子交换层析柱和SephadexG-150凝胶柱进行分离纯化得纯化多糖。气相色谱分析所得多糖的单糖组成。结果:淡肤根石耳精制多糖的单糖组为甘露糖、葡萄糖、半乳糖,其含量之比为16.00:50.96:6.17、淡肤根石耳纯化多糖的单糖组成为甘露糖、葡萄糖、半乳糖,其含量之比为2.97:17.70:1.52;网脊石耳精制多糖的单糖组成为甘露糖、葡萄糖、半乳糖,其含量之比为3.90:38.086:2.00、网脊石耳纯化多糖只含葡萄糖,含量为5.37%。结论:网脊石耳和淡肤根石耳都含有葡萄糖,含有少量的甘露糖和半乳糖。     

超声波辅助提取桦褐孔菌子实体中多糖的工艺优化

研究了优化超声提取桦褐孔菌中多糖的工艺.以蒸馏水为提取剂,用超声波辅助提取桦褐孔菌多糖类物质,以不同处理条件、超声功率、超声次数、超声处理时间为试验因素,以多糖的提取率为考察指标进行单因素试验确定最佳提取工艺.超声辅助技术提取桦褐孔菌子实体中多糖类的最佳工艺条件为:超声功率400W,超声20次,超声10min,在此条件下,多糖得率最高,为11.62％.     

长根菇多糖的分离提取

为提高多糖提取率,以提取温度、时间、次数和水料比为考察因素,采取响应面法优化和建立长根菇子实体多糖的提取工艺。在单因素试验基础上,根据中心组合原理,采用三水平三因素法,确定各工艺条件的最佳条件。研究结果表明:响应面法对长根菇多糖的提取条件进行优化合理可行,最佳提取工艺为提取次数3次、提取温度84℃、提取时间2.3 h、水料比20∶1(m L∶g)。此时多糖提取率达5.85%,为长根菇多糖的纯化和工业化生产提供依据。     

枸杞多糖提取工艺的研究

以枸杞为原料,对其多糖成分提取工艺进行研究。采用单因素试验法对影响枸杞多糖提取率的主要因素进行分析研究,然后利用正交试验法优化提取枸杞多糖的最佳工艺条件。枸杞多糖提取的最佳条件为提取温度90℃,料水比1：30（W：V）,提取时间2h。在最佳提取工艺条件下,枸杞多糖的一次提取率为10．76％。     

微波辅助提取猕猴桃根多糖工艺优化

以猕猴桃根为原料,研究其多糖的微波辅助提取工艺条件。采用单因素试验和正交试验,探讨料液比(猕猴桃根粉：蒸馏水)、提取温度、提取时间、微波功率等对猕猴桃根多糖提取率的影响,并以提取率为评价指标,优化提取工艺。实验结果表明：微波辅助提取猕猴桃根多糖的最佳工艺条件为料液比1:20(g/mL)、提取温度60℃、提取时间15min、微波功率600W,在此条件下猕猴桃根多糖的提取率为11.34%。     

超声波辅助提取桦褐孔菌子实体中多糖和三萜

研究了优化超声辅助提取桦褐孔菌中多糖和三萜类物质的工艺。以蒸馏水和异丙醇为提取剂,用超声波辅助提取桦褐孔菌多糖和三萜类物质,以不同处理条件、超声功率、超声次数、超声处理时间为试验因素,以多糖和三萜的提取率为考察指标进行单因素实验确定最佳提取工艺。超声辅助技术提取桦褐孔菌子实体中多糖类和三萜类物质的最佳工艺条件为:超声功率400 W、超声20次、超声10 min,在此条件下多糖得率最高,为11.62%,总三萜类物质得率在2%,使得多糖和三萜类物质二者共提取得率达到13.57%。     

灰树花子实体多糖和蛋白的同步提取工艺优化

对同步提取制备灰树花子实体多糖和蛋白的工艺进行研究,采用单因素实验研究料液比、提取温度、提取液pH、提取时间对灰树花子实体中多糖和蛋白提取率的影响,并通过正交实验法对提取工艺进行优化。结果表明,影响灰树花蛋白提取率的主次因素依次为:料液比提取温度提取时间pH;影响灰树花多糖提取率的主次因素依次为:提取温度pH提取时间料液比;确定灰树花多糖和蛋白的同步提取最佳工艺条件为提取温度85℃,浸提时间4 h,液料比为60:1,提取液pH为11。在此条件下,蛋白的提取率为29.33%,提取率为36.42%,多糖的提取率为20.34%,提取率为23.52%。     

仙草多糖提取工艺的优化

目的对仙草多糖碱液提取工艺条件进行优化。方法研究碱提法提取仙草多糖的条件,考察碱浓度、提取温度、提取时间及液料比等因素对仙草多糖得率的影响。在单因素实验的基础上,选取碱浓度、提取时间及液料比3因素应用响应面中Box-Benhnken设计原理进行试验设计,以仙草多糖提取率为响应值,建立多糖提取率的二次回归方程,得到碱液提取多糖的最佳条件。结果仙草多糖提取的最佳浸提条件:Na HCO_3 1.25%,提取时间3h,液料比35:1(V:m),在此条件下仙草多糖提取率为8.10%。结论碱液提取法能够提高仙草多糖的提取率。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press