纤维素酶预处理法提取郁金中姜黄素的研究

提出了纤维素酶预处理法提取郁金中姜黄素的新工艺。探讨了酶的用量、酶解时间、酶解pH值、酶解温度、提取次数、提取时间等因素对姜黄素提取率的影响。筛选出了最佳的单因素工艺条件为:每10g郁金粉纤维素酶的用量为180U、酶解时间120min、pH值3.5、温度50℃、提取次数2次、提取时间90min。与传统提取方法相比,该方法及其新工艺能显著提高姜黄素的提取率。     

复合酶法提取洋葱多糖的研究

本文以洋葱为原料,以多糖提取率为考察指标,用苯酚-硫酸法测定多糖的总糖含量。采用正交试验确定了纤维素酶、木瓜蛋白酶和果胶酶的最佳配比为18∶5∶10,进而采用中心组合设计对洋葱多糖的复合酶法提取工艺进行了优化。结果表明:在提取温度55℃、时间120min、pH为5.0、酶用量为0.4%、料液比为1∶40(m/V)时,洋葱多糖提取率为3.27%,多糖含量高达50.5%,实验重现性好。     

响应面法优化微波提取翻白草总黄酮

利用响应面法研究了翻白草总黄酮的微波辅助提取工艺.在单因素试验的基础上,以乙醇体积分数、液固比、提取温度、微波时间为自变量,总黄酮的得率为响应值,研究各因素及其交互作用对黄酮得率的影响.结果表明其最佳提取条件是:乙醇体积分数55%、液固比32 m L/g、温度82℃、微波时间10 min.此条件下,翻白草中黄酮的提取率为6.96 mg/g,与理论预测值基本吻合.     

“红七星”大蒜油提取工艺研究

以乙醇提取法提取温江大蒜("红七星")油,通过考察各影响因素对温江大蒜油提取率的影响,最终确定最佳提取工艺是酶解p H值为6.5、酶解温度40℃、酶解时间1.5 h、料液比1∶4、95%乙醇、在35℃下萃取1.5 h,总提取率为0.35%。通过深入研究乙醇提取法提取温江大蒜油的工艺研究,为温江大蒜的产业提升提供理论基础。     

脐橙皮中黄酮类化合物与果胶的分离和提取研究

黄酮类化合物是具备主要生物活性的天然产物,果胶是人体7大营养素中膳食纤维的主要成分.实验就黄酮和果胶提取分别作L9(34)和L16(44)正交化实验.工艺条件表明,提取黄酮的较佳工艺条件是:固液比1∶30,超声处理时间55 min,处理温度50℃,浸提液浓缩得到粗黄酮.提取黄酮后的脐橙皮渣中提取果胶的较佳工艺条件是:70℃的温度,提取时间为55 min,pH=2.0,固液提取比为1∶25.     

微波预处理复合酶法浸提茶皂素工艺条件研究

以油茶饼粕为原材料,采用微波预处理复合酶法,通过单因素试验研究了液固比、温度、时间、pH值和复合酶用量对油茶饼粕中茶皂素提取率的影响,采用正交试验确定最佳提取工艺条件。结果表明在时间为1.5 h、液固比为9∶1、pH值为6、浸提温度为55℃、复合酶用量为0.45%的条件下,茶皂素的提取率为13.35%,产品纯度为58.47%。     

星点设计-响应面法优化麦冬总黄酮提取工艺及其抗氧化活性的研究

在单因素试验的基础上,利用星点设计-响应面法来优化酶提取法提取麦冬总黄酮的提取工艺,同时利用DPPH法和Fenton法测定总黄酮提取液清除1,1-二苯基-2-三硝基苯肼自由基和羟基自由基的能力.结果表明麦冬总黄酮酶提取法的最佳提取工艺条件:酶用量为46.61 mg,酶解时间为4.14 h,酶解温度为55.56℃,提取率...     

超声辅助浸提-紫外分光光度法测定酸枣中黄酮

建立超声辅助浸提法提取酸枣中黄酮的方法。以雅安碧峰峡野生酸枣为研究对象,通过单因素实验考察提取条件对黄酮提取率的影响,采用自由基清除(DPPH)法研究果皮粗黄酮提取物的抗氧化活性。在料液比为1∶30(g/m L),乙醇体积数为80%,浸泡时间为4 h,超声温度为80℃,超声时间为30 min时提取黄酮效果最好,果皮中黄酮含量为7.76%。果皮粗黄酮提取物对DPPH具有较好的抗氧化活性,其半数抑制浓度(IC50)为0.517 1 mg/mL。测定结果的相对标准偏差为0.54%(n=6),加标回收率在93.5%～100.6%之间。该方法具有较好的精密度与准确度,适用于酸枣中黄酮的提取。     

川佛手中多酚类物质的微波和超声波联合提取工艺优化

采用微波和超声波提取技术,实现了川佛手中多酚类物质的有效提取.在微波功率800 W和微波提取时间40 min的条件下,通过单因素实验条件优化,考察了超声功率、乙醇浓度、提取温度、超声时间和提取料液比对提取效率的影响;通过正交试验设计,确定了最佳提取工艺条件参数,即超声功率800 W、乙醇体积分数60%、提取温度55℃、超声时间1.0 h和提取料液比1∶20 g/m L;通过验证实验,得到川佛手多酚的提取率约为20.79 mg/g.     

酶法纯化茶皂素的工艺研究

采用淀粉酶、糖化酶、纤维素酶和蛋白酶对茶皂素进行纯化水解,探讨了温度、p H、时间等因素对茶皂素纯化效果的影响。结果表明,通过酶法可以提高茶皂素的纯度,当温度50℃、p H=7、水解时间24 h的条件下,酶可使茶皂素的纯度由67.5%提高到90%以上。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.