为解决部分婴幼儿配方食品中矿物元素检测不均的问题,采用干法、湿法、微波法和复溶-微波法对样品进行消解检测,结果表明:干法消解的数据质量最差;湿法与微波消解法检测的结果相比,铜、铁、钾、镁、锰和钠的含量差异不显著(P>0.05),...为解决部分婴幼儿配方食品中矿物元素检测不均的问题,采用干法、湿法、微波法和复溶-微波法对样品进行消解检测,结果表明:干法消解的数据质量最差;湿法与微波消解法检测的结果相比,铜、铁、钾、镁、锰和钠的含量差异不显著(P>0.05),部分矿物元素(铜、铁、钾、钠、磷、锌)检测结果的相对标准偏差(relative standard deviation,RSD)减小,但未达到预期。样品复溶后进行微波消解检测发现,用水复溶后的大部分元素含量偏低,特别是铁,且检测的矿物元素RSD均较大,而用5%硝酸复溶后,元素含量均没有明显偏高和偏低,且RSD均明显减小。因此,通过5%硝酸复溶样品后进行微波消解检测婴幼儿配方食品中的矿物元素,可以解决样品中矿物元素测定结果不均的问题。展开更多
In vitro models of human colon carcinoma cell line(Caco-2 cell monolayer) and human intestinal bacteria were used to investigate the intestinal transport and biotransformation of resibufogenin and cinobufagin in Chan ...In vitro models of human colon carcinoma cell line(Caco-2 cell monolayer) and human intestinal bacteria were used to investigate the intestinal transport and biotransformation of resibufogenin and cinobufagin in Chan Su by HPLC/APCI-MSn. The experimental results of Caco-2 cell monolayer demonstrate that the apparent permeability coefficients(Papp) of resibufogenin and cinobufagin are higher than 10–6 cm/s, which indicates that both resibufogenin and cinobufagin have a good absorption in the small intestine. And the biotransformation result of human intestinal bacteria shows that resibufogenin has been transformed to 3-epiresibufogenin and cinobufagin has been transformed to 3-epicinobufagin, deacetylcinobufagin and 3-epideacetycinobufagin, respectively.展开更多
文摘目的探究灵芝菌固态发酵下夏秋梅占红茶的风味特征。方法采用高效液相色谱法(high performance liquid chromatography,HPLC)、电子舌(electronic tongue,E-tongue)与气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS)相结合,利用多元统计分析,对夏秋梅占灵芝菌茶的滋味与香气品质特征进行判定。结果与夏秋梅占红茶相比,梅占灵芝菌茶在滋味与香气特征上具有差异,HPLC检测结果显示儿茶素类、咖啡碱类苦涩味物质及部分氨基酸类物质含量显著下降,电子舌结果表明甜味响应值增加,苦味、鲜味响应值降低。其中梅占灵芝菌茶中脯氨酸、没食子酸、儿茶素没食子酸与苦味特性呈显著负相关,天冬氨酸、丙氨酸与涩味特性呈显著负相关,丙氨酸与鲜味特性呈极显著正相关,没食子儿茶素与鲜味特性呈显著正相关。挥发性成分上,建立正交偏最小二乘法-判别分析(orthogonal partial least squares-discriminant analysis,OPLS-DA)模型,选取模型中变量重要性投影(variable importance in the projection,VIP)值>1的香气化合物作为关键香气差异特征化合物,经筛选共得到48个,其中酮类6个,醛类9个,醇类15个,酯类7个,酸类化3个,其他芳烯类、呋喃等烷烃类8个,共有8个化合物相对含量上升,40个化合物相对含量下降。结论在灵芝菌影响下,对夏秋梅占红茶滋味与香气特征具有改善作用,此研究为夏秋茶的品质改善与多元化利用提供了新路径。
文摘为解决部分婴幼儿配方食品中矿物元素检测不均的问题,采用干法、湿法、微波法和复溶-微波法对样品进行消解检测,结果表明:干法消解的数据质量最差;湿法与微波消解法检测的结果相比,铜、铁、钾、镁、锰和钠的含量差异不显著(P>0.05),部分矿物元素(铜、铁、钾、钠、磷、锌)检测结果的相对标准偏差(relative standard deviation,RSD)减小,但未达到预期。样品复溶后进行微波消解检测发现,用水复溶后的大部分元素含量偏低,特别是铁,且检测的矿物元素RSD均较大,而用5%硝酸复溶后,元素含量均没有明显偏高和偏低,且RSD均明显减小。因此,通过5%硝酸复溶样品后进行微波消解检测婴幼儿配方食品中的矿物元素,可以解决样品中矿物元素测定结果不均的问题。
基金Supported by the National Natural Science Foundation of China(Nos.30772721 and 30873360)
文摘In vitro models of human colon carcinoma cell line(Caco-2 cell monolayer) and human intestinal bacteria were used to investigate the intestinal transport and biotransformation of resibufogenin and cinobufagin in Chan Su by HPLC/APCI-MSn. The experimental results of Caco-2 cell monolayer demonstrate that the apparent permeability coefficients(Papp) of resibufogenin and cinobufagin are higher than 10–6 cm/s, which indicates that both resibufogenin and cinobufagin have a good absorption in the small intestine. And the biotransformation result of human intestinal bacteria shows that resibufogenin has been transformed to 3-epiresibufogenin and cinobufagin has been transformed to 3-epicinobufagin, deacetylcinobufagin and 3-epideacetycinobufagin, respectively.