木耳多糖提取工艺研究

本文讨论了黑木耳多糖的提取方法,实验结果表明,采用酶法可显著提高多糖提取率,其最佳提取条件为:料水比1:60,浸提温度80℃,浸提时间2.5h,中性蛋白酶用量650IU/g,作用温度43℃,作用时间1.5h,最适pH值7.4;纤维素酶用量375IU/g,作用温度43℃,作用时间1.5h,最适pH值5.3。木耳多糖提取率为4.38%。     

超声波协同果胶酶提取黑木耳粗多糖

采用超声波协同果胶酶提取黑木耳粗多糖,先加入底物质量分数1%的果胶酶,在pH=5.0,50℃酶解2 h,对黑木耳进行预处理。再通过正交试验,得到超声波辅助提取黑木耳粗多糖的最佳工艺条件为:超声波功率400 W,超声波时间7 min,料液比1∶80(g/mL),浸提温度90℃,浸提时间2 h,在此条件下得到黑木耳粗多糖提取率为19.84%。在相同条件下,该提取率高于热水直接浸提法和超声波辅助热水提取法得到黑木耳粗多糖的提取率。实验表明,采用超声波协同果胶酶提取黑木耳粗多糖是可行的。     

超声波辅助酶法提取北五味子多糖工艺研究

建立了超声波辅助复合酶(纤维素酶/蛋白酶/果胶酶=1∶1∶1)提取北五味子多糖的方法。以多糖的提取率为研究指标,通过设计正交试验和响应面优化试验,对超声波辅助复合酶法提取北五味子多糖的工艺进行了优化。确定最佳工艺条件为酶解温度45℃,缓冲液pH 4.6,复合酶用量2%,酶解时间为2.0h,超声波功率166W,萃取温度56℃,萃取时间39 min。在此最佳条件下,北五味子多糖提取量达到105.36mg/g。超声波辅助复合酶法应用到多糖的提取领域,节省了时间,降低了溶剂消耗,且明显提高了多糖的提取率,该法操作方便,简单易行,为北五味子多糖工业化生产提取提供了理论依据。     

黑木耳多糖的提取工艺优化及抗氧化活性研究

以黑木耳为原料,研究超声波辅助提取黑木耳中多糖的工艺条件和体外抗氧化活性。以多糖提取率为评价指标,通过单因素试验和正交试验探讨料液比、超声时间、超声温度、超声功率对黑木耳多糖提取率的影响,并探索其抗氧化活性。结果表明:超声波辅助优化黑木耳多糖的最佳提取工艺条件为料液比1∶40(g/m L)、超声时间20 min、超声温度50℃、超声功率100 W,在此条件下,黑木耳多糖平均提取率为9.69%。     

复合酶法提取红枣多糖工艺研究

以红枣为材料,运用正交实验法研究不同复合酶用量、提取温度、pH和提取时间对红枣多糖提取率的影响,结果表明：复合酶添加量1.0 g/100 g,提取温度48℃,pH5.2,提取时间2.2 h,红枣多糖的提取率最高,提取率为4.61 g/100 g。复合酶法优于热水浸提法。     

超声波辅助复合酶法提取芦荟多糖的研究

利用超声波辅助复合酶法提取芦荟多糖,并对比有无超声波辅助下复合酶法提取所得芦荟多糖的提取率。选取超声波功率、提取时间、提取温度、复合酶添加量进行单因素和正交试验,以芦荟多糖的提取率为指标进行优化。确定芦荟多糖的最佳提取工艺为：超声波功率100W,提取时间50min,提取温度50℃,复合酶添加量为2%（纤维素酶与果胶酶配比为3∶1）。此条件下,芦荟多糖的提取率为8.42%,较单纯的复合酶法提取率提高41.3%,且提取的芦荟多糖具有较强的抗氧化能力。     

超声波法提取茶薪菇粗多糖的工艺

用水浸提辅以超声波处理法从茶薪菇中提取粗多糖。研究了浸提过程中的主要因素:浸提温度、总浸提时间、超声波作用时间、液料比对粗多糖提取率的影响,并用正交实验确定了茶薪菇粗多糖浸提的最佳工艺条件:40℃,总提取时间为4 h,超声波作用50 min,液料比为40:1,在此条件下粗多糖提取率为9.43%。     

超声波协同纤维素酶法提取霍山石斛多糖的研究

为了获得较高的多糖提取率,采用超声波协同纤维素酶法提取霍山石斛多糖;研究了料液比、纤维素酶用量、酶解温度、酶解时间、超声波功率和超声时间等因素对多糖提取的影响,同时通过正交实验对其提取条件进行了优化.结果表明,最佳提取工艺条件为:料液比1:40(g/mL)、纤维素酶500U/g、酶解温度40℃,酶解时间3h,超声波功率为300W,超声时间6min,此时的多糖提取量达到0.283g/g.     

超声波协同复合酶法提取香菇多糖的工艺优化

优化超声波协同复合酶法提取香菇中多糖成分的工艺。以香菇多糖提取率为评价指标,采用单因素试验和正交试验,确定最佳提取工艺参数。结果表明,超声波提取优化工艺条件为:料液比1∶15(g/mL),超声温度70℃,超声时间12 min。在此最佳超声提取条件下香菇多糖提取率为8.97%。在超声波优化的基础上,进行复合酶处理,最佳酶解工艺参数为:酶解时间50 min,复合酶(木瓜蛋白酶∶纤维素酶∶果胶酶=1∶1∶1,质量比)添加量3%,酶解温度60℃,酶解pH5.5,在此优化条件下香菇多糖提取率为12.46%。     

超声波辅助提取金耳多糖的工艺优化

以干燥金耳为原料,采用超声波辅助提取金耳多糖,优化其提取工艺。通过单因素试验和正交试验得到最佳提取工艺。其结果表面:影响金耳多糖提取率的主要因素是超声浸提温度与超声波浸提功率;金耳多糖的最佳提取工艺为料液比为80mL/g,超声波处理时间为30min,超声波处理功率为400W,浸提时间为30min,浸提温度为70℃。采用此工艺,金耳多糖的得率为17.36%,其得率明显提高。     

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.     

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