微生物法测定婴幼儿奶粉中泛酸含量的研究

Determination of pantothenic acid in infant milk powder by microbiological method

目的:优化微生物法测定婴幼儿奶粉中泛酸含量的测定条件,为泛酸检测国标法的后续修订提供试验数据。方法:分析了国标法测定泛酸过程中有待改善的问题,并对检测过程中的菌液制备、前处理及吸光度测定等关键步骤进行重点探讨研究。结果:ATCC和CICC来源的植物乳杆菌均可用于测定泛酸;以直接接种透光率为80%的菌液至测试管中,或以5mL菌液添加至400mL灭菌测试培养基,得到的标准曲线及测定的样品结果最佳;直接提取法的结果较水解法高;酶标仪和紫外分光光度法测定结果相对偏差在5%以内,其中酶标仪法测定加标回收率达到了96.9%,相对标准偏差(RSD)为4.95%,更具优势。结论:微生物法测定泛酸的关键步骤经优化后,可简化操作过程,提高测定样品的准确性,其优化条件可作为泛酸检测国标法的后续修订的参考依据。

Objective:This study aimed to optimize the determination conditions of pantothenic acid content in infant milk powder by microbiological method and provide test data for the subsequent revision of the national standard method for pantothenic acid detection.Methods:The issues covering the determination of pantothenic acid by the national standard method were analyzed,and the key steps in the detection process,including bacterial solution preparation,pretreatment,and absorbance determination,were emphatically studied.Results:Lactobacillus plantarumfrom ATCC and CICC can be used to determine pantothenic acid.The best results were obtained by directly inoculating80%bacterial solution concentration into the test tube,or adding5 mL bacterial solution to 400 mL sterilization test medium.The results of direct extraction were higher than that of hydrolysis.The relative deviation of enzymole-plate and UV spectrophotometry was less than 5%.The recovery rate was 96.9%,and the relative standard deviation(RSD)was 4.95%.Conclusion:The optimization of the key steps in the determination of pantothenic acid by microbiological method can simplify the operation process and improve the accuracy of the samples,and the optimized conditions can be used as a reference for the subsequent revision of the National standard method for pantothenic acid determination.