4种蛋白质分析方法在液态乳中的适用性研究  

Applicability study of four methods for determining protein in milk

作　　者：赵静[1] 傅泽田[1] 路勇[2] 黄昕[1] 周丽静[1] 乔艳慧[1] 侯彩云[1] 

机构地区：[1]中国农业大学,北京100083 [2]北京市食品安全监控中心,北京100041

出　　处：《中国乳品工业》2010年第6期43-46,共4页China Dairy Industry

基　　金：农业科技成果转化资金项目(2009GB23600525);科技部星火计划项目(2007EA600004)

摘　　要：分别利用凯氏定氮法、三氯乙酸-双缩脲比色法、考马斯亮蓝法和福林-酚法等4种方法,对液态乳中添加尿素、甘氨酸、硝酸铵、亚硝酸钠、水解蛋白、三聚氰胺等非蛋白含氮物后的蛋白质量浓度进行了测定,并与其理论值进行了比较。结果表明:凯氏定氮法和福林-酚法测定的液态乳蛋白质量浓度与其理论值存在显著差异,而考马斯亮蓝法和三氯乙酸-双缩脲比色法则能较好地反映其真实的蛋白含量。考马斯亮蓝法灵敏度高,适合测定蛋白含量较低的样品;而三氯乙酸-双缩脲比色法的测定结果与液态乳中真实蛋白质量浓度更加接近。The contents of protein were determined using Kjeldahl nitrogen method,trichloroacetic acid and biuret method,coomassie brilliant blue method and lowry after adding urea,glycine,ammonium nitrate,sodium nitrite,hydrolyzed protein and melamine in milk,and the results were compared with true protein of milk.It is shown from the results that there a very significant difference between the protein conttent of milk determined using Kjeldahl nitrogen method and lowry with true protein of milk,while the protein content of milk determined using coomassie brilliant blue method and trichloroacetic acid and biuret method is close to the true protein of milk.The sensitivity of coomassie brilliant blue method is high,so that coomassie brilliant blue method suitable for determination of milk with low protein content;while the protein content determined using trichloroacetic acid and biuret method is closer to true protein.

关 键 词：三氯乙酸-双缩脲比色法 凯氏定氮法 考马斯亮蓝法 福林-酚法 蛋白质 液态乳 

分 类 号：TS252.7[轻工技术与工程—农产品加工及贮藏工程]