| 摘要: |
| 用GB/T5413.1《婴幼儿配方食品和乳粉蛋白质的测定》、GB/T 21704—2008《乳与乳制品中非蛋白氮含量的测定》和ISO8968-5:2001/IDF 20-5:2001《Milk-Determination of nitrogen content-Part 4:Determination ofprotein nitrogen content》3种国内外现行标准方法,对液态乳中添加三聚氰胺后的蛋白质、非蛋白氮和蛋白氮含量进行了测定,并与双缩脲比色法和三氯乙酸-双缩脲比色法测定的蛋白质含量进行了比较。结果表明:利用前3种标准方法分别测定液态乳添加三聚氰胺后的蛋白质、非蛋白氮和蛋白氮含量,误差率依次为46.60%、93.00%和52.70%;利用双缩脲比色法和三氯乙酸-双缩脲比色法测定液态乳添加三聚氰胺后的真蛋白含量,误差率分别为2.87%和2.22%,比上述3种标准方法更为准确,说明它们既可以排除添加尿素、甘氨酸等非蛋白氮的干扰,又可以准确测定液态乳中的蛋白质含量;其中三氯乙酸-双缩脲比色法比双缩脲比色法的适用性更广。 |
| 关键词: 液态乳 蛋白质 标准方法 双缩脲比色法 三氯乙酸-双缩脲比色法 |
| DOI：10.11841/j.issn.1007-4333.2009.02.029 |
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| 基金项目:国家“863”项目资助(20060110Z2005);;科技部星火计划项目(2007EA600004) |
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| Research on the methods of protein determination after added melamine in milk |
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| Abstract: |
| The contents of protein,non-protein nitrogen and protein nitrogen were determined using GB/T5413.1,GB/T 21704-2008 and ISO 8968-5:2001/ IDF 20-5:2001 methods after adding melamine in milk,and the results were compared with the standard methods,the Biuret Spectrophotometry methord(B method) and Trichloroacetic acid and Biuret Spectrophotometry method(T+B method).It is shown from the results that the error rates were 46.60%,93.00% and 52.70% respectively for the methods of GB/T5413,GB/T 21704-2008 and ISO 896... |
| Key words: milk protein standard methords Biuret Spectrophotometry methord Trichloroacetic acid and Biuret Spectrophotometry methord |
