检验食品中蛋白质含量标准测定方法的改进

Improvement of the determination method for protein content standard in foods

目的改进国家标准GB 5009.5-2010《食品安全国家标准:食品中蛋白质的测定》,第一种方法:凯氏定氮法中蛋白质的含量测定方法。方法用工业液体NaOH替代GB 5009.5-2010中规定的固体NaOH,对食品中蛋白质含量进行测定,并对测定结果进行对比分析。结果实验结果显示,用工业液体NaOH替代固体NaOH,对食品中蛋白质含量进行测定,2种方法平均值绝对值差占算术平均值的0.12%,替代方法引入的不确定度仅占测量值的1%,远低于GB 5009.5-2010精密度10%的要求。结论实验结果证明,使用工业液体NaOH代替固体NaOH,不仅测定结果精确,而且可以大大节约检验成本、提高工作效率、过程安全、可靠,有利于生态环境保护。

Purposes--To improve the determination of protein content in Kjeldahl nitrogen meth- od, the first method in National food safety standard： Determination of protein in foods （GB 5009.5- 2010）. Methods--The solid NaOH in GB 5009.5-2010 was replaced with industrial liquid NaOH to de- termine the protein content in foods and then the results were compared and analyzed. Results--Ex- perimental results showed that the absolute deviation of the mean value takes up 0.12 % of arithmetic mean value in the determination of protein content in foods with solid NaOH and industrial liquid NaOH, the uncertainty of the introduction of alternative method was only 1%, which is far lower than 10% stipulated in the GB 5009.5-2010. Conclusion--The experiment results prove that the a- bove-mentioned replacement not only has accurate results but also can greatly save the inspection cost, lower carbon emissions, promote process safety, improve work efficiency as well as protect the eco- logical environment.