【作者】 孔令瑶；

【导师】 汪云；

【作者基本信息】 江南大学 ， 分析化学， 2008， 硕士

【摘要】 黑米是一种古老而名贵的稻种,因其表皮呈黑色而得名。黑米往往不像白米那样精加工,多半在脱壳之后以“糙米”的形式直接使用,米糠和胚芽部分得以保存,所以黑米具有很高的营养价值。本课题的研究方向是,黑米色素的组成结构分析及黑米中一些生物活性物质测定方法的研究。主要内容包括三个部分:1黑米色素的组成及结构分析;2毛细管电泳电化学检测分离测定黑米米糠中的手性肌醇和肌醇;3毛细管电泳-电化学法检测发芽黑米胚芽中γ-氨基丁酸含量。第一部分,黑米色素属天然花青苷色素,有较强的清除自由基和抗氧化的能力,是一种具有药用价值的天然食用色素资源。实验采用液质联用(LC-MS)与毛细管电泳电化学检测(CE-ED)技术对黑米色素进行定性分析。结果表明,黑米色素主要含有两种花青苷色素,分别是矢车菊素-3-葡萄糖苷和芍药素-3-葡萄糖苷。第二部分,肌醇是黑米中另外一种具有生物活性的保健因子。肌醇即环己六醇,它共有九个异构体,其中肌-肌醇(MI)和手性肌醇(DCI)是常见的存在形式。用CE-ED方法对黑米中这两种物质进行同时分离测定。以直径140μm铜圆盘电极为工作电极,50 mmol/ L硼砂(pH 9.24)为运行缓冲液,检测池内为0.1 mol/L的NaOH溶液,研究了检测电位、分离电压和进样时间等实验参数对分离、检测的影响,得到了优化的测定条件。在优化条件下,两物质在14 min内得到良好的分离。第三部分,采用OPA为柱前衍生化试剂,用CE-ED方法测定发芽黑米胚芽中γ-氨基丁酸的含量。为了比较毛细管电泳的分离效果,同时还检测了与γ-氨基丁酸具有相似结构的亮氨酸和缬氨酸的含量。以直径为300μm的碳圆盘电极为工作电极,50 mmol/L硼砂(pH 8.2)为运行缓冲液,对上述三组分的分离检测条件进行优化研究。在优化条件下,三组分可在15 min内完全分离。结果表明发芽黑米样品中三种氨基酸的含量均高于未发芽黑米样品中三种氨基酸的含量。更多还原

【Abstract】 Black rice, an ancient and precious rice species, is named because of its black color. Unlike other species of rice, black rice is eaten in the form of brown rice, namely the rice only without the outside layer (the hull) of whole grain, which makes the least damage to the nutrition since most nutrients are reserved without further processing. In this work, the components and structures of black rice pigment and the analytical methods of some biological activity materials in black rice were studied. The thesis mainly includes the following three parts: 1.The analysis of components and structures of black rice pigment. 2. Determination of Myo-inositol and D-chiro-inositol in black rice bran by capillary electrophoresis with electrochemical detection (CE-ED). 3. Determination ofγ-aminobutyric acid in germinated black rice germ by CE-ED method.Firstly, black rice pigments is a natural anthocyanin pigments, which has strong antioxidant and free radical scavenging capacity. Liquid chromatography-mass spectrometry (LC-MS) and CE-ED method were applied to determine the components and structures of black rice pigment. The result showed that there were two major anthocyanins in black rice pigment: cyanidin-3-glucoside and peonidin-3-glucoside.Secondly, Inositol, another important active ingredient in black rice, is also known as hexahydroxycyclohexane that has nine different forms. The well-known and nutritionally active forms are myo-inositol (MI) and D-chiro-inositol (DCI). CE-ED was developed for simultaneous determination of myo-inositol and D-chiro-inositol in black rice bran. A 140μm diameter copper-disk electrode was used as working electrode, which exhibited good response for the two analytes in 50 mmol/L sodium hydroxide solution, The optimum conditions for determination was optimized with regard to the potential applied to the working electrode, concentration of the running buffer, separation voltage and injection time. The analytes were separated within 20 min.Finally, using o-phthaldehyde (OPA) as a pre-column derivative agent, the contents of leucine, valine andγ-aminobutyric acid in germinated black rice germ were determined by CE-ED method. A 300μm diameter carbon disk electrode was used as the working electrode and the 50 mmol/L borax solution (pH 8.2) was used as running buffer. The effects of working potential, injection time and separation voltage were investigated. Under the optimum condition, three analytes were base-line separated within 15 min. The result indicated that the contents of amino acids from germinated black rice were higher than those in ungerminated black rice.更多还原