食品科学

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微波消解-电导率法快速测定花叶滇苦菜中粗蛋白

高向阳1,3,高遒竹2,王长青3,刘要卫1   

  1. 1.郑州科技学院食品科学与工程学院,河南 郑州 450064;2.江南大学食品学院,江苏 无锡 214122;
    3.河南农业大学食品科学技术学院,河南 郑州 450002
  • 出版日期:2014-11-25 发布日期:2014-12-09
  • 基金资助:

    河南省重点学科建设项目(10466-X-082301)

Rapid Determination of Crude Protein in Sonchus asper by Microwave Digestion-Conductivity Titration

GAO Xiang-yang1,3, GAO Qiu-zhu2, WANG Chang-qing3, LIU Yao-wei1   

  1. 1. School of Food Science and Engineering, University for Science and Technology of Zhengzhou, Zhengzhou
    450064, China; 2. School of Food Science and Technology, Jiangnan University, Wuxi 214122, China;
    3. College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, China
  • Online:2014-11-25 Published:2014-12-09

摘要:

建立一种快速、简便测定食品中蛋白质的方法,以郑州地区花叶滇苦菜为样品,以硝酸-过氧化氢混酸为消解剂,利用微波技术进行快速消解,将蛋白质中的氮转化为NH4+。根据单因素试验确定中性甲醛的用量后,用中性甲醛将弱酸根NH4+转化为强酸H+,以NaOH标准溶液进行电导滴定。结果表明,花叶滇苦菜干基样品中粗蛋白的平均含量为20.16%,平行测定的相对标准偏差为2.5%(n=6)。与标准方法对比测定,经F检验和t检验表明这2 种测定方法无显著性差异,置信度为95%,结果令人满意。该方法具有快速、简便、准确、节省试剂、污染小、不需要指示剂等优点。

关键词: 花叶滇苦菜, 微波消解, 电导率, 粗蛋白

Abstract:

A rapid and simple method to determine crude protein content in Sonchus asper was established in this study.
Samples were digested with nitric acid-hydrogen peroxide by microwave digestion technique to convert crude protein to
NH4+. The NH4+ generated in the digestion was further converted to H+ ions by neutral formalin for conductivity titration with
standard NaOH solution. The results indicated that the average content of protein in wild Sonchus asper from Zhengzhou
was determined to be 20.16% with relative standard deviation (RSD) of 2.5% (n = 6). Compared with the classic method,
the conductivity titration method did not exhibit significant difference as analyzed by F-test and t-test at 95% confidence
level. This method has the advantages of convenient operation, high sensitivity, quick determination, accurate results and no
requirements for indicators.

Key words: Sonchus asper, microwave digestion, conductivity, crude protein

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