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研究了碳源、氮源、无机盐对双孢菇胞外多糖产量的影响.在单因素实验的基础上,采用响应面实验设计对双孢菇(Agaricus bisporus)深层发酵生产胞外多糖的培养基进行了优化,并建立了葡萄糖、KH2PO4、蛋白胨变化的二次回归方程,探讨了各因子对胞外多糖产量的影响.最终确定适宜的培养基条件为葡萄糖35.7g/L,KH2PO42.1g/L,蛋白胨3.1g/L;在此条件下可得到胞外多糖的最大产量,预测值为1.86g/L,对实验结果进行验证,得到胞外多糖的产量为1.87g/L. 相似文献
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响应面法优化枯草芽孢杆菌产胞外多糖培养基 总被引:1,自引:0,他引:1
从酒药中分离筛选出一株产胞外多糖枯草芽孢杆菌(Bacillussp.)。以胞外多糖的产量为指标,通过响应分析法对细菌胞外多糖产生的发酵培养基进行了初步研究。首先利用单因子实验对培养基中不同成分及添加量进行优化,然后在此基础上利用Box-Behnken中心组合实验设计对影响胞外多糖产量的因素进行优化分析,从而获得最适产胞外多糖的培养基组成。研究结果表明,枯草芽孢杆菌产胞外多糖最佳培养基组成为(g/L):蔗糖25.449、蛋白胨15.229、柠檬酸三钠2.971、牛肉膏3.0、硫酸镁1.0,在此条件下枯草芽孢杆菌胞外多糖的产量为3.554g/L。 相似文献
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《食品与发酵工业》2019,(23):55-59
为提高双歧杆菌BB12胞外多糖(exopolysaccharide,EPS)的产量,并探究其抗氧化活性,该文通过单因素试验分析初始p H值、培养温度和培养时间对胞外多糖产量的影响,在此基础上通过响应面法进一步优化发酵工艺参数,并对胞外多糖的还原能力、·OH和·O_2~-的清除作用进行了研究。结果表明,最优发酵条件修正后为:初始p H值8、培养温度37℃、培养时间101 h。在此条件下进行发酵验证,得到的胞外多糖产量为(131. 6±0. 82) mg/L。体外抗氧化性试验表明双歧杆菌胞外多糖具有还原能力,对·OH和·O_2~-的50%清除浓度(IC_(50))均低于抗坏血酸(Vc)。为双歧杆菌胞外多糖的大规模生产及抗氧化机制的研究提供了可靠的理论依据。 相似文献
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利用冬虫夏草头孢菌发酵生产胞外多糖,研究不同温度下对菌体生长和胞外多糖产量的影响。结果表明:26℃是菌体生长的最适温度,28℃是产物积累的最适温度。在此基础上,提出分阶段控制温度工艺。通过响应面法分析,得到优化方案为第一阶段温度26℃,变温时间17 h,第二阶段温度28.5℃,胞外多糖产量10.92 g/L,比28℃恒温培养提高了25.5%。 相似文献
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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. 相似文献
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John Gilbert Catherine Simoneau David Cote Achim Boenke 《Food Additives & Contaminants》2000,17(10):889-893
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. 相似文献
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Yoko Uematsu Keiko Hirata Kumi Suzuki Kenji Iida Kazuo Saito 《Food Additives & Contaminants》2001,18(2):177-185
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. 相似文献
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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. 相似文献
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Sophie Guillot Laurence Peytavi Sylvie Bureau Renaud Boulanger Jean-Paul Lepoutre Jean Crouzet Sabine Schorr-Galindo 《Food chemistry》2006
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. 相似文献
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Jesus Simal-Gandara Miguel Sarria-Vidal Arjen Koorevaar Rinus Rijk 《Food Additives & Contaminants》2000,17(8):703-711
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. 相似文献
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Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates 总被引:2,自引:0,他引:2
A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel. 相似文献
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Dupuis L Manfait M Serpier H Capon F Kalis B 《International journal of cosmetic science》1997,19(1):37-44
This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration. 相似文献
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《印刷工业》2014,(6):95-95
Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R&D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways. 相似文献