凯氏定氮法测定豆类粗蛋白含量的消解条件探究

Study on the digestion conditions of crude protein content in legumes by Kay type nitrogen

以凯氏定氮法为理论基础,以样品质量、硫酸添加量、消解温度、消解时间为试验变量,通过单一变量试验和正交试验,以4种常见豆类为研究对象,探究豆类样品的最优消解条件。试验表明:消解温度对蛋白含量的测定具有显著影响,消解时间次之,而硫酸添加量和样品添加量对试验结果影响不明显。以大豆为例,通过正交试验发现,当称样量为0.40 g,消解温度为430℃,消解时间为60 min,硫酸添加量为10 mL时,样品消解效果最佳,所测粗蛋白含量最大,高达54.50%。

Based on theory of the Kay type nitrogen determination,the optimal digestion conditions for legume samples were discussed by single variable and orthogonal test.Four types of legume were tested with the variables of sample quality,sulfuric acid addition amount,digestion temperature and digestion time.The test showed that the digestion temperature had a significant effect on the determination of protein content,and the digestion time was second,while the amount of sulfuric acid added and the amount of sample added did not have significant effect on the test results.Taking 0.40 g soybean as example,orthogonal test found that best digestion effect was reached under 430℃at the time of 60 min by 10 mL sulfuric acid addition which obtain the largest coarse crude protein content as high as 54.50%.