中华牛肝菌多糖的性质及抗氧化活性

中华牛肝菌经热水抽提、乙醇分级沉淀制备多糖(BSP80),测定BSP80的平均分子量大小、单糖组成及其抗氧化活性。结果显示,BSP80的主要平均分子量为53.73 ku,并含有少量4 ku的组分;BSP80主要含有半乳糖、葡萄糖和甘露糖,并含有一定量的半乳糖醛酸和葡萄糖醛酸,阿拉伯糖未检出。BSP80具有较好的还原能力和清除羟自由基能力,其中清除羟自由基的IC50为398.21μg/m L。此外,BSP80能够显著降低H2O2诱导的Hep G2细胞内ROS含量,同时提升细胞内SOD酶活性,且呈一定剂量关系。      

铝合金中元素Cr和Cu的双脉冲激光诱导击穿光谱检测

采用共线双脉冲激光诱导击穿光谱(Dual pulse laser induced breakdown spectroscopy, DP-LIBS)技术分析铝合金中微量元素含量,详细研究了共线双脉冲光谱信号强度与 双脉冲间时间延迟的关系,最佳延时为8$\sim$9 $\mu$s。在该延时条件下,双脉冲光谱信号强度比单脉冲光谱 信号强度增强了10倍以上。分别采用双脉冲激光诱导击穿光谱和单脉冲激光诱导击穿光谱(Single-pulse laser induced breakdown spectroscopy, SP-LIBS)技术,得到了以Cu I 324.75 nm, Cr I 425.43 nm 谱线为分析线 的定标曲线。与采用单脉冲激光诱导击穿光谱技术相比,铝合金中 Cu和 Cr的检测极限分别由单脉冲时的169.5 和94.5 $\mu$g/g降低至双脉冲时的21.46 和4.26 $\mu$g/g。     

凉薯(Pachyrrhizus erosus L.)块茎的营养品质分析

对云南产凉薯块茎中基本营养成分及其含量、多酚含量及其组成、多酚提取物的抗氧化活性进行了研究。结果表明:云南产凉薯块茎富含水溶性糖和淀粉,VC的含量为11.55mg·100g-1鲜重（FW）;B族维生素中B3和B6含量较高,分别为0.166和0.207mg·100g-1FW;多酚含量为2.06mg·g-1干重（DW）,其中没食子酸、香草酸、咖啡酸和芦丁为主要成分,含量分别为0.55、0.27、0.12和0.15mg·g-1DW;多酚提取物表现出与其浓度线性正相关的强抗氧化活性,其在还原能力的EC50值为1.33μg·mL-1,DPPH自由基清除能力、羟自由基清除能力和抑制脂质体过氧化能力的IC50分别为4.15、7.70和17.00μg·mL-1。表明凉薯是一种营养品质较好的食源材料。      

Simultaneous Determination of Trace Lead and Chromium in Water Using Laser-Induced Breakdown Spectroscopy and Paper Substrate

Toxic metals such as lead and chromium in aqueous solutions have been analyzed simultaneously by laser-induced breakdown spectroscopy(LIBS), in which the ordinary printing paper is used as a liquid absorber which was immerged into Pb(NO3)2and Cr(NO3)3aqueous solution to enrich the heavy metals. This method overcomes the drawbacks of splashing and low sensitivity in ordinary LIBS analysis of water, in which a laser beam is directly focused on a liquid surface. A good signal intensity and reproducibility has been demonstrated. The Pb 405.78 nm and Cr 427.48 nm spectral lines are used as the analytical lines. The variation of line intensity with immersion time was investigated. The calibration curve for quantitative measurement of Pb and Cr in water was established, and the detection limits are 0.033 mg/L and 0.026 mg/L respectively,which is about 2-3 orders of magnitude better than that in the ordinary LIBS analysis of heavy metal in solution.     

云南产6种野生食用牛肝菌的营养成分及抗氧化特性研究

本文研究了云南产6种野生食用牛肝菌的氨基酸组成及氨基酸评分、多酚提取物及其抗氧化活性、多糖制取物及其抗氧化活性。结果表明,6种牛肝菌中17种氨基酸种类齐全,含量丰富,氨基酸总量为23.13% DW（B. bicolor）~30.69%DW（B. speciosus）,品种间差异显著（p<0.05）;疏水性氨基酸所占比例较高;天冬氨酸、谷氨酸、甘氨酸、丙氨酸和半胱氨酸是含量最高的氨基酸种类;以总氨基酸为基础,6种牛肝菌氨基酸评分较高,为0.59（B. speciosus）~0.94（B. bicolor）。6种牛肝菌中多酚含量丰富,为1.20 mg GAE/g DW（B. Sinicus）~10.32 mg GAE/g DW（B. speciosus）;多酚提取物的抗氧化活性显著,特别是B. bicolor和B. craspedius表现出显著高于BHT的抑制脂质体过氧化的能力（p<0.05）。6种牛肝菌水溶性粗多糖得率较高,为11.67% DW（B. craspedius）~20.00% DW（B. speciosus）;粗多糖中的60%醇溶组分和40%醇溶组分在不同抗氧化体系中均表现出较好的抗氧化活性。表明6种野生食用牛肝菌的营养价值高,多酚及多糖等功能性成分含量高、抗氧化活性强,是潜在的抗氧化物资源。