酶法提取枸杞多糖的研究

研究了纤维素酶提取枸杞多糖的最佳工艺条件。以提取率为指标,分别考虑了加水量、酶解pH、酶解温度、酶解时间、加酶量对纤维素酶酶解反应的影响。试验确定了纤维素酶酶解工艺的最佳条件为加水量50mL、pH5.0、酶解温度50℃、酶解时间60min、加酶量0.5%。在这种条件下,枸杞多糖的得率为11.2%。     

匙羹藤多糖的酶法提取工艺研究

以匙羹藤叶为原料,研究采用纤维素酶法辅助匙羹藤中多糖的提取工艺。通过单因素和正交试验,探讨酶解温度、pH值、料液比、酶用量对匙羹藤中多糖得率的影响,确定最佳提取工艺。结果表明:最佳酶解工艺条件为料液比为1:10、酶解时间为90min、酶解pH值为4.5、纤维素酶浓度为0.6%,在此优化条件下,提取匙羹藤中多糖的得率为5.83%,粗提液中多糖含量为27.34%。     

纤维素酶法提取决明子粗多糖的工艺优化及其抗氧化活性

目的:优化纤维素酶法提取决明子粗多糖的工艺,并研究决明子粗多糖的体外抗氧化活性。方法:在单因素实验的基础上,以酶解时间、酶解温度、酶用量、液料比及酶解pH为自变量,多糖得率为响应值,利用BoxBehnken响应面法进行工艺优化。以对DPPH自由基和羟自由基清除率的大小为指标考察决明子粗多糖的体外抗氧化活性。结果:纤维素酶法提取决明子粗多糖最佳工艺为酶用量1.4%、酶解时间50 min、液料比24:1 mL/g、酶解pH5.4、酶解温度48℃,此条件下决明子多糖得率为11.67%,与回归模型的理论预测值11.91%误差小于5%。决明子粗多糖对DPPH自由基和羟自由基均具有较强的清除作用,半数抑制浓度分别为1.025 mg/mL和0.894 mg/mL。结论:纤维素酶法可显著提高决明子粗多糖得率,工艺简便可行,获得的决明子粗多糖具有体外抗氧化活性。     

微波辅助复合酶法提取枸杞多糖及其抗氧化活性研究

采用微波辅助复合酶法提取枸杞多糖。以多糖得率为指标,在单因素试验的基础上通过响应面法优化提取工艺,并评价其抗氧化活性。结果表明：最佳提取工艺为纤维素酶∶果胶酶∶蛋白酶质量比3∶1∶2、加酶量7%(以枸杞质量计)、酶解时间2.50 h、微波时间4 min、酶解温度52℃、酶解pH 5.2,在此条件下,枸杞多糖得率为24.37%±1.65%,制得的枸杞多糖对DPPH·和ABTS⁺·的清除率分别为62.07%、 47.82%,表明其具有较好的抗氧化活性。     

酶法提取黄芪多糖的工艺优化

运用Box-Behnken中心组合响应面分析法优化纤维素酶法提取黄芪多糖的工艺条件,探讨了酶解过程中酶解pH值、温度和加酶量对多糖提取含量的影响。优化工艺方案为:酶解pH4.0,温度56.5℃,加酶量61U/ g,其多糖的平均含量达到20.31%。     

纤维素酶法提取太子参块根粗多糖工艺的优化

利用纤维素酶法提取太子参块根粗多糖,并考察了料液比、酶用量及提取时间对块根粗多糖得率的影响。正交试验结果表明,优化后的太子参粗多糖提取工艺参数为:酶用量0.25 g,料液比1∶5,提取时间2 h,重复提取3次,在此条件下太子参粗多糖得率可达28.9%,粗多糖纯度达51.8%。优化的纤维素酶提取工艺,能提高块根粗多糖得率和总糖提取率,这为太子参粗多糖工业化生产提供理论依据。     

罗汉果粗多糖的提取工艺优化及其压片糖果的研制

本文以罗汉果为原料,采用纤维素酶协同水提醇沉法提取罗汉果粗多糖,通过单因素实验分析酶解pH、纤维素酶用量、酶解时间、酶解温度对罗汉果粗多糖得率的影响,应用响应面法对提取工艺进行优化,结果表明,罗汉果粗多糖最佳提取工艺参数为:酶解pH5.9、纤维素酶用量0.8%、酶解温度50 ℃、酶解时间62 min,该工艺参数下罗汉果粗多糖得率为6.64%,与模型预测基本一致。基于罗汉果消炎、抗氧化等药用价值,进一步研制罗汉果压片糖果,通过单因素实验考察罗汉果粗多糖、硬脂酸镁、阿斯巴甜和甘露醇的添加量对压片糖果感官品质的影响,应用正交试验优化配方,研究表明,经优化的罗汉果压片糖果配方为:罗汉果粗多糖20%、硬脂酸镁1.5%、阿斯巴甜3%、甘露醇60%,感官评分90分,依此配方所制压片糖果入口清凉、色泽均匀、无砂粒感。     

响应面试验优化复合酶法提取碎米荠多糖工艺及其抗氧化活性

利用人工种植的碎米荠为原料,研究其粗多糖的提取工艺参数及抗氧化活性。首先对提取条件的单因素进行优化,在单因素试验基础上,进行提取条件的响应面优化。单因素优化条件为:质量分数2%复合酶(m(纤维素酶)∶m(果胶酶)=2∶1)、酶解时间90 min、酶解温度60℃、酶解pH 4.0。响应面优化结果为:酶解时间91.8 min、酶解温度57.1℃、酶解pH 4.17。在此条件下,碎米荠粗多糖提取率最高,粗多糖提取率预测值为4.14%,验证实验得到实际粗多糖的平均提取率为4.07%;与理论预测值相比,其相对误差约为1.62%。抗氧化活性研究结果显示,碎米荠多糖具有抗氧化活性,且效果优于VC。该实验结果为碎米荠多糖的提取以及多糖的性质研究提供理论依据。     

响应面优化酶法提取龙眼多糖工艺

对纤维素酶法提取龙眼果肉多糖(ELP)的工艺进行研究。以新鲜龙眼果肉为原料,考察不同酶种类对龙眼多糖提取得率的影响,选择纤维素酶用于酶法提取实验研究。采用单因素试验和响应面法对影响龙眼多糖得率的4个主要影响因素即纤维素酶添加量、酶解温度、酶解时间和液料比进行分析优化。结果表明：影响龙眼多糖得率的工艺因素按主次顺序排列为：纤维素酶添加量＞酶解温度＞酶解时间＞液料比;确定纤维素酶解龙眼多糖最佳工艺条件为纤维素酶添加量1.2%、液料比6:1(mL/g)、酶解温度45.0℃、酶解时间187.0min。在此最佳条件下,纤维素酶法提取龙眼多糖的得率为(12.23 ± 0.15)mg/g。本研究采用纤维素酶解提取工艺,相对于传统热水浸提法可显著提高龙眼多糖得率。     

新疆红枣多糖酶法提取工艺研究

以新疆红枣为原料,利用纤维素酶对红枣多糖进行提取,通过响应面设计优化最佳提取工艺,旨在提高红枣多糖提取含量。实验证明,酶添加量0.85mg/mL、酶解时间60min、酶解温度50.0℃、液料比10:1为红枣多糖最佳提取条件,其多糖提取含量达7.71%。通过对上述各种因素的优化,确定了红枣多糖的最佳提取条件,为相关生产加工企业提供一定的参考依据和理论支持。     

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