石墨消解-全自动凯氏定氮法测定液体乳中的蛋白质及其方法验证  

Determination of Protein in Liquid Emulsion by Graphite Digestion-Kjeldahl Nitrogen Analyzer and Verification of the Method

作　　者：郝琴 HAO Qin(Miluo City Food and Drug Inspection Institute,Yueyang 414400,China)

机构地区：[1]汨罗市食品药品检验所,湖南岳阳414400

出　　处：《食品安全导刊》2024年第1期74-76,共3页China Food Safety Magazine

摘　　要：采用石墨消解仪消解,全自动凯氏定氮仪蒸馏滴定,建立液体乳中蛋白质含量的测定方法。结果表明,蒸馏时样品取1.0~2.5 g、硫酸取5 mL、硫酸铜和硫酸钾用量分别为0.1 g和1.5 g,消解滴定时加碱量为25 mL、硼酸10 mL、稀释水20 mL、蒸馏时间5 min,该条件下检测效果最佳。选择10种代表性液体乳进行方法验证,所得结果均符合国家标准要求。与传统凯氏定氮法相比,该方法操作简单、安全、高效,适用于液体乳蛋白质的日常检测。A method for determining protein content in liquid milk was established by using a graphite digestion instrument for digestion and a fully automatic Kjeldahl nitrogen analyzer for distillation and titration.The results showed that during distillation,the sample volume was taken as 1.0~2.5 g,sulfuric acid was taken as 5 mL,copper sulfate and potassium sulfate were used as 0.1 g and 1.5 g,respectively.During digestion titration,25 mL of alkali was added,10 mL of boric acid was added,20 mL of diluted water was added,and distillation time was 5 minutes.Under these conditions,the best effect was achieved.Ten representative liquid emulsions were selected for the validation of this method,and the results obtained all met the requirements of national standards.Compared with the traditional Kjeldahl method,this method is simple,safe,and efficient,and is suitable for daily detection of liquid milk proteins.

关 键 词：石墨消解仪 全自动凯氏定氮仪 蒸馏 滴定 

分 类 号：TS252.7[轻工技术与工程—农产品加工及贮藏工程]