刺葡萄皮色素的提取及性能测定

对刺葡萄果皮色素的溶剂法提取工艺在单因素水平基础上进行了研究,并对提取所得色素的理化性质进行了测定.结果表明:以80%的乙醇水溶液为提取剂,料液比为1:5,在80℃条件下提取1.5h,提取效果最好,提取得率为2.2%;对提取所得色素的理化性质进行的测定结果表明:所得色素色价高,耐酸性d、耐光性好,Mg2 、Cu2 、K 等金属离子对其稳定性影响不大,具有很好的开发应用前景.     

鸡冠花叶色素的提取及理化性质研究

本文研究了鸡冠花叶色素的提取条件和理化性质,结果表明,用料液比1∶50（g/mL）、10%乙醇作提取剂,在80℃恒温浸提60min,提取效率较好.鸡冠花叶色素属黄酮类色素,pH值对色素影响明显,低温时比较稳定.光照能加快色素降解.金属离子Na^＋、Ca^2＋、Al^3＋、Zn^2＋对色素色泽无影响,而Cu^2＋、Fe^3＋、Pb^2＋有不良影响.色素抗氧化还原性能较好.蔗糖、柠檬酸和盐等添加剂对色素无影响.     

莴笋叶绿色素的提取与性质研究

研究了莴笋叶绿素的提取及理化性质，结果表明，在30%丙酮及5%氢氧化钠溶液中易于提取，得到绿色粉末状色素，该色素对光，热和糖类具有较好的稳定性。     

红花继木叶红色素的提取及性质研究

研究了红花继木叶色素的提取条件和理化性质，结果表明，用料液比1：40、pHl的80％乙醇作提取剂、在80℃恒温浸提40min，提取效率较好。红花继木叶色素属花青素类色素，pH值对色素影响明显，60℃以内比较稳定。光照能加快色素降解。金属离子Na^＋、Ca^2＋、Al^3＋、Cu^2＋、Zn^2＋对色素色泽无影响，而Fe^3＋、Pb^2＋有不良影响。色素的抗氧化能力较差而耐还原性能较好。蔗糖、葡葡糖和盐等添加剂对色素无影响。     

益母草花红色素的提取及理化性质研究

研究了益母草花红色素的提取条件和理化性质，结果表明，用1：50（g／mL）的pH1的盐酸水溶液，在80℃恒温浸提1．5h，提取效率较好。益母草花红色素属花青素类色素；pH值对色素影响明显：在酸性条件下色泽稳定且具有热稳定性；光照能加快色素降解；金属离子Na^＋、Ca^2＋、Cu^2＋、Al^3＋、Zn^2＋对色素色泽无影响，而Fe^3＋、Pb^2＋有不良影响；色素的抗氧化能力较差而耐还原性能较好；蔗糖、葡葡糖和盐等添加剂对色素无影响。     

石榴皮色素理化性能的研究

对石榴皮色素的提取及理化性质作了研究，结果表明该色素宜于碱性条件下使用，耐热性好，葡萄糖、蔗糖对色素的稳定无影响，大部分金属离子对色素色泽无影响。     

以微波-超声波法提取草毒色素及对其理化性质的研究

研究了微波和超声波对草莓色素提取的影响 ,通过单因素分析和正交试验设计确定了最佳提取工艺条件 ,并对草莓色素的理化性质进行了进一步研究。试验结果表明 ,最佳提取工艺条件为微波功率 62 4W ,微波处理时间 60s ,超声波处理时间 40s ,物液质量比为 1∶6。pH值对草莓色素的影响明显 ,该色素在 pH值 5 0以下稳定 ;在温度低于 80℃时草莓色素基本上是稳定的 ;蔗糖对色素影响不明显 ,柠檬酸具有明显的增色和护色作用 ;苯甲酸钠和山梨酸钾对色素都有一定的降解作用 ,并且质量分数 >0 0 1%时降解作用十分明显。     

郁金香红色素的提取及性质研究

研究了郁金香花红色素的提取条件和理化性质。结果表明，用料液比1：30（g／mL）、pH1（10％盐酸调）的95％乙醇作提取剂、在80℃恒温提取20min，提取效率较好。郁金香花红色素属花青素类色素，易溶于水和酸性乙醇；pH值对色素影响明显，在酸性条件下色泽稳定且具有热稳定性。光照能加快色素降解。金属离子Na^＋，Ca^2＋，A^13＋，Cu^2＋，Zn^2＋对色素色泽无影响，而Fe^3＋，Pb^2＋有不良影响。色素的色素抗氧化较好而抗还原性能较差。蔗糖、葡萄糖和盐等添加荆对色素无影响。     

木槿花红色素的提取及理化性质研究

本文研究了木槿花红色素的提取条件和理化性质，结果表明，用料液比1：30（g／mL）、pH1（10％盐酸调）的95％乙醇作提取剂，在80℃恒温浸提60min，提取效率较好。木槿花红色素属花青素类色素，pH值对色素影响明显，在酸性条件下色泽稳定且具有热稳定性。光照能加快色素降解。金属离子Na^＋、Ca^2＋、Al^3＋、Cu^2＋、Zn^2＋对色素色泽无影响，而Fe^3＋、Pb^2＋有不良影响。色素抗氧化能力较差而耐还原性能稍好。蔗糖、葡葡糖和盐等添加剂对色素无影响。     

黑豆皮色素的提取及其理化性质研究

通过对黑豆皮色素提取方法的研究，确定其最佳提取条件为：０．８％盐酸酒精（Ｖ／Ｖ）提取液，７５℃恒温，１：２５０物料比，１ｈ提取时间。在此条件下，提取３次，得率可达９１．２％，所得色素浸膏经理化性质研究，确定该色素具有花色苷色素性质，适于用作天然食用色素。     

Arsenic(III) oxidation by iron(VI) (ferrate) and subsequent removal of arsenic(V) by iron(III) coagulation

We investigated the stoichiometry, kinetics, and mechanism of arsenite [As(III)] oxidation by ferrate [Fe(VI)] and performed arsenic removal tests using Fe(VI) as both an oxidant and a coagulant. As(III) was oxidized to As(V) (arsenate) by Fe(VI), with a stoichiometry of 3:2 [As(III):Fe(VI)]. Kinetic studies showed that the reaction of As(III) with Fe(VI) was first-order with respect to both reactants, and its observed second-order rate constant at 25 degrees C decreased nonlinearly from (3.54 +/- 0.24) x 10(5) to (1.23 +/- 0.01) x 10(3) M(-1) s(-1) with an increase of pH from 8.4 to 12.9. A reaction mechanism by oxygen transfer has been proposed for the oxidation of As(III) by Fe(VI). Arsenic removal tests with river water showed that, with minimum 2.0 mg L(-1) Fe(VI), the arsenic concentration can be lowered from an initial 517 to below 50 microg L(-1), which is the regulation level for As in Bangladesh. From this result, Fe(VI) was demonstrated to be very effective in the removal of arsenic species from water at a relatively low dose level (2.0 mg L(-1)). In addition, the combined use of a small amount of Fe(VI) (below 0.5 mg L(-1)) and Fe(III) as a major coagulant was found to be a practical and effective method for arsenic removal.     

Mind the (yield) gap(s)

This paper explores the origin of the notion of ??yield gap?? and its use as a framing device for agricultural policy in sub-Saharan Africa. The argument is that while the yield gap of policy discourse provides a simple and powerful framing device, it is most often used without the discipline or caveats associated with the best examples of its use in crop production ecology and microeconomics. This argument is developed by examining how yield gap is used in a selection of recent and influential agricultural policy documents. The message for policy makers and others is clear: ??mind the (yield) gap(s)??, for they are seldom what they appear.     

Iron(VI) and iron(V) oxidation of copper(I) cyanide

Copper(Il) cyanide (Cu(CN)4(3-)) in the gold mine industry presentsthe biggest concern in cyanide management because it is much more stable than free cyanide. Cu(CN)4(3-) is highlytoxic to aquatic life; therefore, environmentally friendly techniques are required for the removal of Cu(CN)4(3-) from gold mine effluent. The oxidation of Cu(CN)4(3-) by iron-(VI) (FeVIO4(2-), Fe(VI)) and iron(V) (FeVO4(3-), Fe(V)) was studied using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 5HFeO(4-) + Cu(CN)4(3-) + 8H2O - > 5Fe(OH)3 + Cu2+ + 4CNO- +3/202 + 6OH-. The rate law for the oxidation of Cu(CN)4(3-) by Fe(VI) was found to be first-order with each reactant. The rates decreased with increasing pH and were mostly related to a decrease in concentration of reactive protonated Fe(VI) species, HFeO4-. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate constant for the oxidation of Cu(CN)4(3-) by Fe(V) was determined at pH 12.0 as 1.35 +/- 0.02 x 10(7) M(-1) s(-1), which is approximately 3 orders of magnitude larger than Fe(VI). Results indicate that Fe(VI) is highly efficient for removal of cyanides in gold mill effluent.     

Supercritical fluid extraction (SFE) of 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI) from ground-coffee with high-performance liquid chromatographic-electrospray mass spectrometric quantification (HPLC/ESI-MS).

Two polar analytes, 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI), were extracted with supercritical carbon dioxide (CO2) modified with aqueous methanol. The method was applied to a roasted coffee powder with good recovery rates. Method efficiency was compared with that of solid-phase extraction using SCX Disc cartridges and validated for spiked solid matrix. The analytes were determined using isocratic liquid chromatography-mass spectrometry (LC/MS) on an Atlantis HILIC Silica column (150 x 2.1 mm, 3 microm) with 80% methanol and 20% 0.01 mol l-1 ammonium formate as the mobile phase. The limit of quantification was around 1.5 pg for 4-MeI and 2.0 pg for THI. The linearity of the calibration curves was satisfactory as indicated by correlation coefficients of >0.999. The coefficient of variation for the intra-day and inter-day precisions was <4% (n = 6). Accuracy was in the range 98-101%; recovery rates were > or = 98 and > or = 99% for THI and 4-MeI, respectively. Several samples of Arabica coffee from various locations and commercially available 'off-the-shelf' coffee products (Arabica/Robusta mixtures) were analysed to test the method.     

Reduction of Tc(VII) by Fe(II) sorbed on Al (hydr)oxides

Under oxic conditions, Tc exists as the soluble, weakly sorbing pertechnetate [TcO4-] anion. The reduced form of technetium, Tc(IV), is stable in anoxic environments and is sparingly soluble as TcO2 x nH2O(s). Here we investigate the heterogeneous reduction of Tc(VII) by Fe(II) adsorbed on Al (hydr)oxides [diaspore (alpha-AlOOH) and corundum (alpha-Al2O3)]. Experiments were performed to study the kinetics of Tc(VII) reduction, examine changes in Fe surface speciation during Tc(VII) reduction (M?ssbauer spectroscopy), and identify the nature of Tc(IV)-containing reaction products (X-ray absorption spectroscopy). We found that Tc(VII) was completely reduced by adsorbed Fe(II) within 11 (diaspore suspension) and 4 days (corundum suspension). M?ssbauer measurements revealed thatthe Fe(II) signal became less intense with Tc(VII) reduction and was accompanied by an increase in the intensity of the Fe(III) doublet and magnetically ordered Fe(III) sextet signals. Tc-EXAFS spectroscopy revealed that the final heterogeneous redox product on corundum was similar to Tc(IV) oxyhydroxide, TcO2 x nH2O.     

表没食子儿茶素没食子酸酯的甲基化分子修饰

研究表没食子儿茶素没食子酸酯(EGCG)的甲基化分子修饰。以碘甲烷作为甲基供体,采用化学合成方法研究EGCG 的甲基化分子修饰,并通过HPLC-MS 和NMR 等对反应产物进行结构鉴定。结果表明：采用化学合成方法能有效完成EGCG 的甲基化分子修饰,并分离鉴定出5 个EGCG 甲基化衍生物,分别为4″-Me-EGCG、4′,4″-di-Me-EGCG、5,3′,4′,5′,3″,4″,5″-hepta-Me-EGCG、5,7,3′,4′,3″,4″,5″-hepta-Me-EGCG、5,7,3′,4′,5′,3″,4″,5″-octa-Me-EGCG。     

Attractancy of diethyl ether extracts of Arachis hypogaea (Linnaeus) (Papilionaceae), Citrullus lanatus (Thunberg) (Cucurbitaceae) and Irvingia gabonensis var. excelsa (Baillon) (Irvingiaceae) to Oryzaephilus mercator (Fauvel) (Coleoptera: Silvanidae)

Volatiles of the diethyl ether extracts of I. gabonensis, C. lanatus and A. hypogaea attracted 1–7 and 28–42-day-old adult O. mercator when tested in a two-choice pitfall Petri dish bioassay. For both age groups, a significant difference was observed in response between fed and starved adults to the different extracts. Differences in starvation time did not affect responses of individuals in the 1–7-day-old group; a significant effect was observed in the 28–42-day-old group.

Adults, 28–42-day-old were significantly more responsive to virtually all extracts than 1–7-day-old adults. Responses of adults in each age group to the different extracts were not significantly different. The time of trial within the period 0900–1900 h did not significantly affect the response of adults in both age groups, starved for 2 days, to any extract.     

优质农业生产管理指导手册(二)

4病虫害综合防治 病虫害综合防治(IPM)是烟叶生产的一项系统体系,利用病虫害预测预报系统,提供最好的病虫害综合防治决策,重点是协调应用一切可行的办法.病虫害综合防治并不意味着完全排除使用农药,而是在使用其它办法不能使病虫害的种群数保持在可接受的范围时适当使用农药.施用农药的地方应确保安全,并遵守一切法律法规.     

优质农业生产管理指导手册(三)

7 烘烤（调制）和烤房管理 烟叶的正确烘烤和烤房管理对优化烟叶的产量、质量和产值来说是非常关键的因素。烟叶烘烤是保持烟叶产量、质量的最后一道环节。烟叶质量会因烘烤不当而降低，而正确进行烘烤能确保烟叶质量的稳定。然而，若将劣质的鲜烟叶或烟株放入烤房，则不可能提高最终的烟叶质量。