超声辅助酶法提取河蚬多糖

选择超声辅助酶法提取河蚬多糖,确定了不同超声时间、超声功率、料水比、酶解时间等因素对河蚬多糖提取率的影响,并进行了正交试验分析。结果表明,最佳提取工艺条件为:超声时间40 min、超声功率80W、料液比1∶30、酶解时间90 min,在此条件下,河蚬多糖的提取率为4.86%。     

酶法提取海参脏器多糖条件优化研究

利用木瓜蛋白酶酶解海参脏器提取多糖,探讨酶解温度、酶解时间、pH值、料液比、加酶量等时海参脏器多糖得率的影响,确定最适提取条件为:酶解温度55℃,pH 8.0,加酶量3.0%,料液比1:30(g/mL),酶解时间4h,在此条件下,海参脏器多糖的得率为14.76%.     

复合酶解法优化黄精多糖提取工艺

采用复合酶解法优化黄精多糖提取工艺,苯酚-浓硫酸显色法测定黄精多糖质量浓度,以黄精多糖提取率为指标,对复合酶种类和配比进行筛选后,在单因素试验基础上,考察酶解温度、pH、料液比、加酶量对提取率的影响,并通过正交试验进行优化。结果表明,复合酶提取优于单酶提取和普通水提。酶用量配比为纤维素酶:木瓜蛋白酶=3∶7。酶解最佳条件为:pH值5.0,酶解温度50℃,料液比(g/mL)1∶20,加酶量1.5 g/dL,即纤维素酶0.45 g/dL,木瓜蛋白酶1.05 g/dL,酶解2 h后,沸水浸提2 h。在此工艺条件下,黄精多糖提取率可达21.55%,是普通水提法得率的2.75倍,比单酶水解高出12.06%。     

鹿角盘成分提取及其工艺的优化

摸索鹿角盘提取条件,优化提取工艺。利用正交试验考察水提法和酶解法对鹿角盘提取率的影响。水提法:料液比1︰25 (g/mL), 100℃煎煮6 h,提取率为28.11%。单酶酶解法:胃蛋白酶酶解工艺为料液比1︰30 (g/mL),pH 1.8,加酶量4%,酶解温度37℃,酶解4 h,提取率为22.39%;胰蛋白酶酶解工艺为料液比1︰20 (g/mL), pH 8.0,加酶量4%,酶解温度55℃,酶解6 h,提取率为20.99%。复合酶解酶解工艺:先胃蛋白酶,处理条件为料液比1︰20 (g/mL),pH 1.8,加酶量1%,酶解温度37℃,酶解12 h;后胰蛋白酶,处理条件为料液比1︰20 (g/mL), pH 8.0,加酶量0.4%,酶解温度37℃,酶解2 h,提取率可达31.84%。按照复合酶解工艺,对水提法最佳条件下提取后的鹿角霜进行复合酶解,提取率仅为1.33%。利用水提和酶解的方法筛选出鹿角盘的最优提取条件,制备工艺合理。由结果看出,两个方法中得到的提取率差异不明显。复合酶解得到的提取物种类和含量多于水提法的种类和含量。     

超声辅助酶法提取柚子皮多糖工艺的响应面优化

以柚子皮为原料,采用超声辅助酶法提取柚子皮多糖。为提高柚子皮多糖提取率,通过响应面法对提取条件进行优化。实验结果表明:柚子皮多糖的最适提取条件为料液比1∶30 g/mL、pH6、加酶量为1.7%、纤维素酶与果胶酶之比1∶1、酶解时间1.2 h、酶解温度50 ℃、超声时间29 min、超声温度70 ℃。在此条件下,柚子皮多糖的平均提取率为82.4%,得率为27.3%,得到的粗多糖纯度46.2%。     

响应面法优化杏鲍菇多糖提取工艺

对杏鲍菇内多糖的提取条件进行研究,首先采用单因素法对影响酶解杏鲍菇水溶性多糖含量的因素以及酶解条件进行选取,然后在单因素试验的基础上,采用响应面法对杏鲍菇多糖的提取工艺进行优化,确定杏鲍菇多糖提取工艺的最佳参数,为其进一步的开发利用提供参考,杏鲍菇经过打浆、酶解后,通过水提醇沉的方法进行多糖的提取。结果表明:酶加量、料液比、pH值、酶解温度和酶解时间对多糖的提取具有明显的影响。杏鲍菇的最佳提取工艺参数为:纤维素酶0.9%、中性蛋白酶0.2%、料液比1∶2(g/mL)、pH 5.5、酶解温度50℃、酶解时间3 h,在该条件下杏鲍菇多糖提取率为3.24%。     

复合酶法提取红雪茶粗多糖工艺优化研究

为了获得复合酶法提取红雪茶粗多糖的最佳工艺,采用单因素实验和正交实验,研究了不同料液比、pH、酶解温度、提取时间和不同复合酶配比对红雪茶粗多糖提取率的影响;在此基础上采用L9(34)正交实验研究了各影响因素对红雪茶粗多糖提取率的影响,结果表明复合酶最佳配比为纤维素酶2.0%,果胶酶2.0%,木瓜蛋白酶0.5%;影响红雪茶粗多糖提取率的四个因素的主次顺序为:料液比>酶解温度>pH>酶解时间;最佳提取工艺条件是料液比1:40,pH4.5,酶解温度40℃,酶解时间80min,在此条件下红雪茶多糖提取率达8.91%。本研究确定了复合酶法提取红雪茶多糖的最佳工艺。     

纤维素酶法提取菠萝皮渣多糖生产工艺研究

利用纤维素酶的酶解作用对菠萝皮渣多糖的提取工艺进行了研究。研究了料液比、加酶量、酶解温度和酶解时间对菠萝皮渣多糖的提取率的影响,并通过正交试验确定纤维素酶法提取菠萝皮多糖的最佳工艺。正交试验结果表明提取菠萝皮渣多糖的工艺最佳条件为酶解温度48℃、酶解时间100min、加酶量0.8%。在该条件下菠萝皮渣多糖的实际提取率为26.3%。该方法与其他类似提取方法相比较具有成本低,速度快,提取率高的优点。     

酶法提取鲍鱼多糖的研究

选用木瓜蛋白酶酶解鲍鱼肉,提取多糖,确定了温度、时间、pH值、料液比、加酶量对鲍鱼多糖得率的影响。结果表明,木瓜蛋白酶的适宜反应条件为温度55℃,时间2h,pH8.0,料液比1∶40,加酶量2.0%,在此条件下,鲍鱼多糖的得率为19.60%。     

超声波辅助酶法优化黄精多糖提取工艺的研究

该文主要以始兴黄精为原料,纯净水为提取溶剂,采用超声波辅助酶法提取黄精多糖,通过单因素试验研究复合酶添加量、酶解时间、酶解温度和料液比等因素对黄精多糖提取率的影响,并对其最佳工艺进行正交试验优化。结果表明,超声波辅助酶法提取黄精多糖的最佳工艺条件为:复合酶添加量6%、酶解温度65℃、酶解时间55 min、料液比1∶30(g/mL),在此工艺条件下得到黄精多糖的提取率为25.63%。     

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.     

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.     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

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.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

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.