傅立叶变换近红外光谱法快速评价涪陵榨菜品质

应用傅立叶变换近红外光谱技术,建立了评价涪陵榨菜品质的定量分析模型.测定了58份涪陵榨菜的近红外光谱数据,通过光谱预处理方法消除噪声,以偏最小二乘法(PLS)建立回归模型.最终得到评价其品质的水分、总酸(以乳酸计)和氨基酸含量近红外光谱分析模型的决定系数(R2)依次为0.957 8、0.975 4、0.950 4,交叉...     

马铃薯酪氨酸酶的性质

用硫酸铵分级沉淀、DEAE SepharoseFF和SephadexG 150柱层析,从马铃薯中分离纯化出酪氨酸酶,纯化倍数50,比活170.03U mg蛋白。SDS PAGE检测呈现一条带。分子量42KD。酶的最适pH7 5,最适温度30℃。该酶具有单酚酶和二酚酶活性,其中以邻苯二酚为底物活性最高,以L DOPA为底物Km值为3 70mmol·L-1。Hg2+、Zn2+、Fe2+为激活剂,K+、Ga2+、Mg2+是抑制剂。Ga2+为非竞争性抑制,抑制常数ki为116 8mmol·L-1,K+为竞争性抑制,抑制常数ki为10mmol·L-1。     

Expression of Potato virus Y cytoplasmic inclusion protein in tobacco results in disorganization of parenchyma cells, distortion of epidermal cells, and induces mitochondrial and chloroplast abnormalities, formation of membrane whorls and atypical lipid accumulation

Infection of plant cells by potyviruses induces the formation of cytoplasmic inclusions ranging in size from 200 to 1000 nm. To determine if the ability to form these ordered, insoluble structures is intrinsic to the potyviral cytoplasmic inclusion protein, we have expressed the cytoplasmic inclusion protein from Potato virus Y in tobacco under the control of the chrysanthemum ribulose-1,5-bisphosphate carboxylase small subunit promoter, a highly active, green tissue promoter. No cytoplasmic inclusions were observed in the leaves of transgenic tobacco using transmission electron microscopy, despite being able to clearly visualize these inclusions in Potato virus Y infected tobacco leaves under the same conditions. However, we did observe a wide range of tissue and sub-cellular abnormalities associated with the expression of the Potato virus Y cytoplasmic inclusion protein. These changes included the disruption of normal cell morphology and organization in leaves, mitochondrial and chloroplast internal reorganization, and the formation of atypical lipid accumulations. Despite these significant structural changes, however, transgenic tobacco plants were viable and the results are discussed in the context of potyviral cytoplasmic inclusion protein function.     

不同分辨率无人机数码影像的马铃薯地上生物量估算研究

地上生物量（AGB）是表征作物生命活动的重要参数,对作物长势监测和产量预测尤为关键。因此,快速准确地获取AGB信息,对于监测作物生长状况、指导农业管理和提高产量具有重要的意义。以无人机为平台搭载数码相机传感器,因机动性强、价格低、空间分辨率高的优势,能够及时准确的估算作物AGB,已成为遥感估算研究的热点之一。由于无人机不同飞行高度及其对应不同分辨率数码影像的AGB估算模型精度不同,因此,尝试在马铃薯的块茎增长期,通过设置10,20,30,40和50 m共5种无人机飞行高度,获取不同分辨率的数码影像,探究其对以光谱信息、纹理特征和光谱信息+纹理特征构建AGB模型精度的影响。首先,基于无人机数码影像,分别提取光谱信息和纹理特征,通过光谱信息构建的植被指数和纹理特征,分别结合地面试验获取的实测地上部生物量数据进行相关性分析,分别筛选了相关系数绝对值较大的前10个影像指数和前8个纹理特征。然后,分别以3种输入变量整合方差膨胀因子（VIF）进行主成分分析（PCA）降维处理,获得最佳主成分后以多元线性回归（MLR）构建AGB估算模型。最后,对比不同分辨率的数码影像以3种变量和同种分辨率下以同种变量构建的AGB估测模型效果。结果发现：（1）获得的影像分辨率在0.43~2.05 cm之间变化时,纹理特征与马铃薯AGB相关性弱于植被指数,但都达到极显著相关水平（p<0.01）,随着数码影像分辨率降低,二者相关性差异明显。（2）同种分辨率影像下,光谱信息+纹理特征估算AGB的效果最优,其次为单一纹理特征模型,而单一光谱模型表现效果最差。（3）随着数码影像分辨率提高,光谱信息、纹理信息以及光谱+纹理信息估算AGB的精度逐渐变好。     

Gas Chromatographic Determination of Glycerides in Potato Crisps Fried in Different Oils

Summary Glycerides in eight commercial potato crisps were identified after conversion to fatty acids. The profiles were analysed and compared, with regard to 14 fatty acids, by use of a gas chromatographic method. Results showed that the fatty acid profile is quite variable among brands and depends on the type of oil used in the frying process. To provide a means of identifying the frying oil correctly, brands were classified into three groups depending on the main fatty acid present. After the first analysis samples were stored at room temperature in the dark and analysed again 1 and 3 months later.Presented at: International Symposium on Seperation and Characterization of Natural and Synthetic Macromolecules, Amsterdam, The Netherlands, February 5–7, 2003     

FT-Raman光谱法无损鉴定药材的真伪

本文利用傅里叶变换拉曼（FT-Raman）光谱法无损快速鉴定了正品大黄与伪品大黄以及有掺伪物的知母样品。结果表明：大黄（西宁大黄）与伪品大黄（华北大黄，山大黄，水根大黄）在拉曼谱图中均有各自的特征峰，可容易地将它们区别开；知母样品中所掺杂的其他饮片，经与白芨的拉曼谱图比对，证实为白芨饮片，该方法具有快速，准确，操作简单，不需对样品进行提取分离，可直接进行测定的特点。     

Determination of acrylamide in food by solid-phase microextraction coupled to gas chromatography-positive chemical ionization tandem mass spectrometry

A method has been developed to determine acrylamide in aqueous matrices by using direct immersion solid-phase microextraction (SPME) coupled to gas chromatography-positive chemical ionization tandem mass spectrometry (GC-PCI-MS-MS) in the selected reaction monitoring (SRM) mode. The optimized SPME experimental procedures to extract acrylamide in water solutions were: use of a carbowax/divinylbenzene (CW/DVB)-coated fiber at pH 7, extraction time of 20 min and analyte desorption at 210 °C for 3 min. A detection limit of 0.1 μg L⁻¹ was obtained. The linear range was 1-1000 μg L⁻¹. The relative standard deviation was 10.64% (n = 7). The proposed analytical method was successfully used for the quantification of trace acrylamide in foodstuffs such as French fries (1.2 μg g⁻¹) and potato crisps (2.2 μg g⁻¹).     

FAAS测定黑马铃薯中的8种微量元素

采用火焰原子吸收光谱法对黑马铃薯中Cu、Zn、Fe、Mn、Ca、K、Mg和Na 8种微量元素进行了分析测定.在选定的测定条件下,黑马铃薯中各元素间相互干扰小,对测定结果无明显影响.方法的校准曲线线性关系良好(r=0.9973-0.9999),方法回收率(n=7)在97.5%-100.3%之间,RSD值(n=7)在1.1...     

Comparison of Immobilisation Procedures for Development of an Electrochemical PPO-Based Biosensor for on Line Monitoring of a Depuration Process

SUMMARY

The development of amperometric biosensors based on polyphenol oxidase (PPO) as a novel tool for the determination of phenolic compounds is described.

Biosensors have been obtained using different PPO-rich matrices: tissue slices from mushroom and potato, acetonic powder from mushroom; lyophilised enzyme from mushroom (tyrosinase-SIGMA). A large variety of immobilisation procedures have been used with pure enzyme and acetonic powder. Behaviour of all biosensors obtained has been investigated in terms of sensitivity. linearity range, response time and half life time. Preliminary experiments have been carried out, using a Flow Injection Analysis, with standard solutions of catechol and phenol in the range 1-10 mM, then biosensors have been also tested on a real sample (green water from crushers) with a direct method and a standard addition, one obtaining good reproducibility.