微生物阻抗法快速测定乳粉中的叶酸含量  

Rapid Determination of the Folic Acid Content in Milk Powder by Microbial Impedance Method

作　　者：张杰[1,2] 朱慧丹 孔欣欣 郭楠楠[1,2] 张中义[1] ZHANG Jie;ZHU Huidan;KONG Xinxin;GUO Nannan;ZHANG Zhongyi(School of Food Science and Engineering,Zhengzhou University of Science and Technology,Zhengzhou 450064,China;Key Laboratory of Food Safety Rapid Detection in Zhengzhou City,Zhengzhou 450064,China)

机构地区：[1]郑州科技学院食品科学与工程学院,河南郑州450064 [2]郑州市食品安全快速检测重点实验室,河南郑州450064

出　　处：《食品科技》2024年第3期293-299,共7页Food Science and Technology

基　　金：郑州科技学院校级大学生创新创业训练计划项目(DC202161);国家级大学生创新创业训练计划项目(202112746011);河南省高等学校重点科研项目(21B550008);郑州科技学院校级科研项目(23010121005)。

摘　　要：为建立一种基于微生物阻抗法快速测定乳粉中叶酸含量的新方法,在GB 5009.211—2022第一法的基础上制作标准系列管,优化测定条件,探索菌体的阻抗变化与叶酸含量之间的线性关系,建立微生物阻抗法标准曲线。以乳粉质控样品和市售乳粉为试验样品,考察此方法的检测性能。结果表明:当标准系列管培养20 h,采用离心+超声破碎处理时,测定菌体的电阻率值与叶酸含量在0.000~0.100 ng/mL之间的线性关系最好。拟合出标准曲线方程为Y=8866.3X+177.38,相关性系数R2=0.9952。检出限为1.26μg/100 g,定量限为4.20μg/100 g,加标回收率为96.2%~103.6%。对乳粉质控样品和4种市售乳粉的相对标准偏差(Relative standard deviation,RSD)值在3.4%~6.4%之间,总检测时间为3 d左右。与国家标准方法相比,该方法的重复性、准确度相当,但检测时间更短,可快速测定乳粉中的叶酸含量。In order to establish a new method for rapid determination of folic acid content in milk powder based on microbial impedance method,the test made a standard series of tubes based on the first method of the national standard GB 5009.211—2022,and optimized the determination conditions of the series tubes,the standard curve of microbial impedance method was established through exploring the linear relationship between the impedance changes of bacterial bodies in various series of tubes and the folate content.And then using milk powder quality control samples and commercially available milk powder as test samples,the detection performance of this method was evaluated.The results showed that when the standard series of tubes were cultured for 20 h and subjected to centrifugation and ultrasonic fragmentation treatment,the linear relationship between the resistivity value of the measured bacterial body and folate content between 0.000 ng/mL and 0.100 ng/mL was the best.The fitted standard curve equation was Y=8866.3X+177.38,with a correlation coefficient of R2=0.9952.The limit of detection was 1.26μg/100 g,the limit of quantification was 4.20μg/100 g,and the recovery was 96.2%-103.6%.The relative standard deviation(RSD)values for quality control samples of milk powder and four commercially available milk powders ranged from 3.4%to 6.4%,and the total detection time was about 3 d.Compared with the national standard method,this method has comparable repeatability and accuracy,but with shorter detection time,which can quickly determine the content of folic acid in milk powder.

关 键 词：叶酸 乳粉 阻抗法 电阻率值 快速测定 

分 类 号：TS207.3[轻工技术与工程—食品科学]