黄芪多糖超声-微波协同提取研究

本论文采用超声-微波协同提取新工艺,通过单因素实验分别考察提取时间、微波功率、料液比等因素对黄芪多糖提取率及纯度的影响;通过正交实验得出最佳提取工艺参数;通过平行提取实验,与水提法、微波及超声波辅助提取进行比照。得出最佳提取条件为微波功率120 W,提取时间为150 s,料液比1∶25(g/mL)时,黄芪多糖的提取率最高达4.25%,并且证明了超声微波协同提取法的提取效率高于水提法、微波法及超声波法等传统的提取方法。     

响应面优化微波-超声波协同提取灵芝三萜工艺及其清除自由基活性

探索微波-超声波协同提取仪对灵芝三萜的提取工艺及提取产物的抗氧化活性,在单因素实验的基础上,选择微波功率、超声波功率、乙醇浓度和提取时间4个因素,通过响应面分析进行灵芝三萜提取工艺的优化。结果显示,在乙醇含量75%、微波功率650W、超声波功率730W、提取时间20min时灵芝三萜的提取率达13.18mg/g,其中灵芝酸A含量为2.5mg/g;抗氧化活性结果表明,灵芝三萜粗提物对DPPH清除效果优于茶多酚。     

淫羊藿生物碱的超声波-微波协同提取及其 对HeLa细胞的抑制作用

建立了药用植物心叶淫羊藿(Epimedium brevicornum)生物碱的超声波-微波协同提取工艺, 探讨了提取机理, 分析了生物碱的化学组成及其对人宫颈癌HeLa细胞增殖的抑制作用。采用正交试验法优化得到了淫羊藿生物碱的超声波-微波协同提取工艺: 浸泡时间为40分钟, 超声波-微波协同作用18分钟, 微波功率250 J∙s^-1, 液固比为30 mL∙g^-1, 乙醇溶液浓度为70%。超声波-微波协同提取法的提取率可达16.146 mg∙g^-1, 显著高于超声波提取法、微波提取法和加热提取法。扫描电子显微镜观察结果表明, 超声波-微波协同作用可使淫羊藿叶片样品表面出现大量裂隙。激光粒度分析显示, 超声波-微波协同提取后, 中、低粒度范围的样品量明显增多, 而高粒度范围的样品量明显减少。薄层色谱和高效液相色谱分析结果表明, 淫羊藿生物碱含有木兰花碱, 不含小檗碱或含量很低。淫羊藿生物碱对HeLa细胞的增殖具有明显的抑制作用, 并且呈现出剂量依赖性。研究结果为药用植物淫羊藿资源的开发利用提供理论依据。     

纤维素酶-超声波协同提取黑木耳黑色素工艺及其抗氧化活性分析

黑色素是黑木耳的主要活性成分之一,在黑木耳的药理活性上发挥着重要作用。为了提高黑木耳黑色素的提取得率,实验采用正交法和响应面法对纤维素酶-超声波协同提取黑木耳黑色素的提取工艺进行了优化,并对最优条件下提取的黑木耳黑色素体外抗氧化活性进行了分析。实验结果表明,纤维素酶-超声波协同提取黑木耳黑色素的最优条件为:酶添加量12mg,酶解温度40℃,酶解pH 5.0,酶解时间120min,NaOH浓度1.27mol/L,料液比1:40,超声功率300W,超声时间52min,超声温度60℃。在最优条件下,黑木耳黑色素提取得率可达到10.48%,相比于实验设置的未添加纤维素酶的超声波组黑色素提取得率提高了12.93%。抗氧化结果表明,采用纤维素酶-超声波协同提取的黑色素相比于未加纤维素酶提取的黑色素清除ABTS、DPPH和羟基自由基的能力更强。研究结果为黑木耳黑色素的高效提取及其产品的应用开发奠定了基础。     

超声-微波协同皂化萃取茄尼醇条件的研究

实验研究了超声-微波协同皂化萃取茄尼醇的工艺条件,确定了其最适工艺参数为:在超声开的条件下,皂化时间60 min,微波功率40 W,氢氧化钠与烟叶浸膏的质量比为1∶2,在此优化条件下茄尼醇皂化回收率为126.3%。与其它皂化法相比,超声-微波协同皂化萃取法具有节省时间、节约能量、茄尼醇回收率高等优点。     

超声波协同酶法提取绞股蓝皂苷的工艺研究

目的:探索超声波协同酶法用于提取绞股蓝总皂苷的可行性.方法:分别采用常规水浴法、单一酶法、单一超声波法、超声波协同酶法等试验方案进行处理结果:超声波和纤维素酶对总皂苷的提取都有明显的促进作用,而采用超声波协同酶法促进效果更为明显,其中酶解后超声波处理比先超声波后酶解的处理方法,绞股蓝总皂苷的提取率更高,达到7.494%,比常规水浴法、单一酶法、单一超声波法分别提高了79.28%、34.37% 、43.04%.结论:超声波协同酶法能显著提高绞股蓝总皂苷的提取率.     

超声波协同热水提取铁钉菜多糖的研究

应用超声波技术,研究了液固比、超声波强度、提取时间、提取温度和pH对铁钉菜多糖提取率的影响。结果表明,超声波提取铁钉菜多糖最佳工艺条件为:料剂比为3:100(g:m l),不调pH值,在65℃,超声强度为70%(210w),超声30 m in。     

微波辐射法合成苄基-2-萘基醚的研究

在微波辐射条件下,以2-萘酚和氯化苄为原料,用氢氧化钠作碱剂,碘化钾作催化剂,以水和N,N-二甲基甲酰胺(DMF)为溶剂合成了苄基-2-萘基醚;采用单因素实验法,考察了反应物的摩尔比、催化剂用量、微波功率、辐射时间等因素对苄基-2-萘基醚产率的影响。实验结果表明:在n(2-萘酚):n(氢氧化钠):n(氯化苄):n(碘化钾)=1:1.1:1:0.018,水7 ml,DMF 25 ml,微波功率320 W和辐射时间75 s的优化条件下,苄基-2-萘基醚的产率可达88.03%。     

微波辅助提取灰树花多糖工艺研究

采用提取时间、微波功率、液料比的单因素试验和正交试验法优化微波辅助提取灰树花多糖条件.结果表明,以净多糖得率为指标,影响微波辅助提取灰树花多糖的主次因素为:提取时间＞微波功率＞液料比,并且提取时间和微波功率的影响达到了极显著水平.灰树花多糖最佳提取工艺条件为:提取时间为10 min,微波功率为80%(全功率为800 W),液料比为25∶1.创立了一种用苯酚-硫酸法测定多糖时排除蛋白质干扰的方法.     

超声波辅助提取盐地碱蓬红色素的工艺研究

为了探讨超声波对盐地碱蓬红色素提取效果的影响,为进一步提取纯化盐地碱蓬红色素提供一定的理论依据,通过单因素和正交实验,研究了不同提取时间、温度、液固比和功率下超声波辅助对盐地碱蓬红色素提取的影响.结果表明:各因素对红色素提取效果的影响程度依次为液田比>温度>功率>时间;最佳提取工艺条件为提取时间50 min,提取温度50℃,液固比15 mL/g,超声功率800 W.超声波对盐地碱蓬红色素的提取具有一定的促进作用.     

Ecofriendly microwave assisted synthesis of some new pyridine glycosides

An efficient, mild and rapid procedure was employed to prepare a novel series of pyridine glycosides. The protocol allows the reaction of 2-pyridone with 1,2,3,4,6-penta-O-acetyl-α-D-glucopyranose under solvent-free microwave-assisted synthesis using different solid supports. Silica gel has been found to be an efficient and environmentally friendly promoter. Structures of the new products were confirmed based on their elemental analyses and spectral data (LC-MS/MS, IR, UV, 1D- and 2D-NMR).     

Hydrolysis of plant seed gums by microwave irradiation

Under microwave irradiation (MW), the seed gums, guar and Ipomoea quamoclit were hydrolyzed to constituent monosaccharides and oligosaccharides in very mild conditions and short reaction time. Under MW both the seed gums could be completely hydrolyzed using very dilute acid (0.00625N H₂SO₄) within two minutes. Hydrolysis occurs in 2 min and 20 s even in absence of acid under the MW irradiation. Thus hydrolytic fragmentation under MW provides an efficient tool in structural elucidation of polysaccharides.     

超临界CO_2和微波辅助萃取艾叶挥发油工艺的研究

通过超临界CO2萃取均匀设计实验和微波辅助萃取艾叶挥发油的正交实验比较,考察影响提取的主要因素,寻求最佳萃取工艺。超临界CO2萃取最佳工艺条件为:萃取压力16MP,萃取温度31℃,CO2流量20kg/h和时间80min,得率3.75%;微波萃取最佳工艺条件为:辐射功率720w,辐射时间200s,溶剂量400mL,洗涤剂量50mL,得率4.85%。水蒸馏法提取率为1.87%。结果表明超临界CO2和水蒸馏法萃取艾叶挥发油品质最好;微波萃取收率最高,但品质较差。     

Protein transduction assisted by polyethylenimine-cationized carrier proteins

Previously, we have reported that cationized-proteins covalently modified with polyethylenimine (PEI) (direct PEI-cationization) efficiently enter cells and function in the cytosol [Futami et al. (2005) J. Biosci. Bioeng. 99, 95-103]. However, it may be more convenient if a protein could be delivered into cells just by mixing the protein with a PEI-cationized carrier protein having a specific affinity (indirect PEI-cationization). Thus, we prepared PEI-cationized avidin (PEI-avidin), streptavidin (PEI-streptavidin), and protein G (PEI-protein G), and examined whether they could deliver biotinylated proteins and antibodies into living cells. PEI-avidin (and/or PEI-streptavidin) carried biotinylated GFPs into various mammalian cells very efficiently. A GFP variant containing a nuclear localization signal was found to arrive even in the nucleus. The addition of a biotinylated RNase A derivative mixed with PEI-streptavidin to a culture medium of 3T3-SV-40 cells resulted in remarkable cell growth inhibition, suggesting that the biotinylated RNase A derivative entered cells and digested intracellular RNA molecules. Furthermore, the addition of a fluorescein-labeled anti-S100C (beta-actin binding protein) antibody mixed with PEI-protein G to human fibroblasts resulted in the appearance of a fluorescence image of actin-like filamentous structures in the cells. These results indicate that indirect PEI-cationization using non-covalent interaction is as effective as the direct PEI-cationization for the transduction of proteins into living cells and for expression of their functions in the cytosol. Thus, PEI-cationized proteins having a specific affinity for certain molecules such as PEI-streptavidin, PEI-avidin and PEI-protein G are concluded to be widely applicable protein transduction carrier molecules.     

Enzymatic synthesis of biodiesel from palm oil assisted by microwave irradiation

Optimal conditions for enzymatic synthesis of biodiesel from palm oil and ethanol were determined with lipase from Pseudomonas fluorescens immobilized on epoxy polysiloxane–polyvinyl alcohol hybrid composite under a microwave heating system. The main goal was to reduce the reaction time preliminarily established by a process of conventional heating. A full factorial design assessed the influence of ethanol-to-palm oil (8:1–16:1) molar ratio and temperature (43–57 °C) on the transesterification yield. Microwave irradiations varying from 8 to 15 W were set up according to reaction temperature. Under optimal conditions (8:1 ethanol-to-oil molar ratio at 43 °C), 97.56 % of the fatty acids present in the palm oil were converted into ethyl esters in a 12-h reaction, corresponding to a productivity of 64.2 mg ethyl esters g^?1 h^?1. This represents a sixfold increase from the process carried out under conventional heating, thus proving to be a potential tool for enhancing biochemical modification of oils and fats. In general, advantages of the new process include: (1) microwaves speed up the enzyme-catalyzed reactions; (2) there are no destructive effects on the enzyme properties, such as stability and substrate specificity, and (3) the microwave assistance allows the entire reaction volume to be heated uniformly. These bring benefits of a low energy demand and a faster conversion of palm oil into biodiesel.     

Image study of pectin extraction from orange skin assisted by microwave

The process of pectin extraction from orange skin assisted by microwave has been researched by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The effects of microwave radiation on organization of the orange skin and the changes on this orange skin organization during the extraction have both been analyzed.     

Matrix assisted refolding of proteins by ion exchange chromatography

Two different approaches of matrix assisted refolding have been evaluated and compared to conventional refolding by dilution. Bovine alpha-lactalbumin was used for the studies as model protein. It was adsorbed under denaturing conditions on an ion exchange matrix and refolding was completed on the column prior to elution or, depending on the buffer system, in the eluate. Agarose based chromatography matrices showed high capacities for the denatured alpha-lactalbumin. A positive effect on the yield of refolded protein by the matrix could be observed for Fractogel EMD DEAE and a negative for Toyopearl DEAE 650M, DEAE Sepharose FF and Q Sepharose FF. In the case of Fractogel EMD DEAE the ion exchange surface might act as a folding helper. This property may be caused by the grafted polymers. For Source 30Q only a marginal negative influence on the refolding kinetics was observed, thus the ion exchanger is only a mean for removal of chaotropic agents. Refolding on the column is characterized by a low yield but high productivity due to significant reduction of refolding time.     

Preparation and characterization of activated carbon from sunflower seed oil residue via microwave assisted K2CO3 activation

Sunflower seed oil residue, a by-product of sunflower seed oil refining, was utilized as a feedstock for preparation of activated carbon (SSHAC) via microwave induced K(2)CO(3) chemical activation. SSHAC was characterized by Fourier transform infrared spectroscopy, nitrogen adsorption-desorption and elemental analysis. Surface acidity/basicity was examined with acid-base titration, while the adsorptive properties of SSHAC were quantified using methylene blue (MB) and acid blue 15 (AB). The monolayer adsorption capacities of MB and AB were 473.44 and 430.37 mg/g, while the Brunauer-Emmett-Teller surface area, Langmuir surface area and total pore volume were 1411.55 m(2)/g, 2137.72 m(2)/g and 0.836 cm(3)/g, respectively. The findings revealed the potential to prepare high surface area activated carbon from sunflower seed oil residue by microwave irradiation.     

Purification and properties of thiamine-binding proteins from sesame seed

Three thiamine-binding proteins of 17-19 kDa (STBP-I, II, and III) were purified from sesame seed (Sesamum indicum L.). Each of the proteins was composed of two subunits of equal molecular mass and each subunit consisted of a large polypeptide and a small polypeptide linked by a disulfide bond(s). They were rich in glutamic acid (or glutamine) and arginine. Their binding activities were optimal at neutral pH. They bound specifically free thiamine but not thiamine phosphates. STBP-I had higher affinity for thiamine than STBP-II or STBP-III. STBP-II and STBP-III bound one molecule of thiamine per molecule, and STBP-I bound 0.5 molecule. The amino acid composition and structure of the STPBs were similar to those of 2S storage proteins.