食品科学 ›› 2004, Vol. 25 ›› Issue (1): 158-160.

• 分析检测 • 上一篇    下一篇

凯氏定氮法测定大米蛋白质时蛋白系数的确定

 王章存, 姚惠源   

  1. 郑州轻工业学院食品与生物工程系,江南大学食品学院
  • 出版日期:2004-01-15 发布日期:2011-10-24

Determination of Conversion Factor of Percent Nitrogen to Percent Protein in Rice Protein

 WANG  Zhang-Cun, YAO  Hui-Yuan   

  1. 1.Department of Food and Biological Engineering, Zhengzhou Institute of Light Industry;2.Department of Food Science & Technology, Southern Yangtze University
  • Online:2004-01-15 Published:2011-10-24

摘要: 本文通过对10个不同来源大米蛋白粉样品氨基酸成分的分析,计算出17种氨基酸含氮量平均值为13.48%,标准差S为0.19,变异系数CV为1.2%,表明重复性很好。通过对天冬酰胺和谷氨酰胺含量范围的设定计算出大米蛋白含氮量变化范围为13.48%~15.78%,即蛋白系数在6.34~7.41之间;进一步通过对高纯度蛋白质样品全成分的分析,确定大米蛋白质的蛋白系数为6.70。经验证计算结果更符合真实情况。

关键词: 大米蛋白质, 蛋白系数, 氨基酸分析

Abstract: The conversion factor of percent nitrogen to percent protein in rice protein was determined by amino acid contentanalysis of ten samples obtained from different areas. The nitrogen contents of amino acid in 10 samples were almost same(N=13.48%, S=0.19, CV=1.4%). Considering the variations of the contents of asparagine (Asn) and glutamine (Gln) in riceprotein, and with the analysis of all compositions in high purity rice protein isolate (RPI), the conversion factor was determinedto be 6.70, which was then verified to be credible.

Key words: rice protein isolate, conversion factor, amino acid content analysis