用SDS滴定奶粉中蛋白质的实验研究  

Experimental Study for Titrating Protein Content in Milk Powder by SDS

作　　者：何莉萍[1] 郝俊[1] 张瑞斌[1] 尹宏雷[1] 

机构地区：[1]天津医科大学卫生化学教研室,天津300070

出　　处：《食品科学》2007年第3期298-300,共3页Food Science

摘　　要：目的:研究用十二烷基硫酸钠(sodium dodecyl sulfate,SDS)快速测定奶粉中蛋白质含量的实验条件。方法:一定量的奶粉用蒸馏水溶解后,在一定介质中用0.1000%的SDS溶液滴定,当被滴定溶液析出凝乳状的白色沉淀时,即为终点。研究了温度、pH值及奶粉中淀粉、蔗糖含量对测定的影响,确定了SDS溶液的滴定量与蛋白质含量的关系。结果:用该方法对同一奶粉测定8次,RSD=0.53%,用本法和凯氏定氮法对8份不同奶粉中的蛋白质含量测定,结果无显著性差异(p>0.05)。结论:该方法简便、准确、可靠,适合于奶粉中蛋白质的快速检测,检验一个样品仅仅用4min。Objectives： To study the experimental conditions for titrating protein content in milk powder by sodium dodecyl sulfate（SDS）. Methods： The milk powder was diluted with distilled water in acidic medium, and then the diluted solution was litrated with SDS in acidic medium. At the endpoint the content of conical flask was suddenly separated into curdy white coagulum The effects of temperature, pH, amylum, sugar and flour in the experiment were studied. The relationship between the liter of SDS soluition against the protein content in milk powder was also studied. Results： With this method the same milk powder was assayed 8 times with RSD=0.53%.The results determined, by this method coincide with those of Kjieldahls method for the 8 different samples （p 〉 0.05）. Conclusions： This method is simple, accurate, dependable and suitable as rapid titration method for the determination of protein in milk powder. The time for assaying every sample is only 4 minutes.

关 键 词：奶粉 蛋白质 滴定 十二烷基硫酸钠 

分 类 号：Q503[生物学—生物化学]