婴幼儿配方乳粉中叶黄素的测定及其储存过程中损失率的研究

Detection method and loss rate of lutein content in infant formula milk powder

目的建立一种婴幼儿配方乳粉中叶黄素含量的测定方法。并确定叶黄素标准储备液的有效期和考察婴幼儿配方乳粉储存和食用过程中叶黄素含量的损失率。方法样品经超纯水溶解后以0.1%BHT-丙酮溶液超声提取。以甲醇-甲基叔丁基醚为流动相等度洗脱,流速为1.0 m L/min,进样量50μL,柱温25℃,二极管阵列检测器检测,检测波长445 nm。结果在15 min内完成目标物的分离分析,叶黄素在0.1、1.0、10.0μg/100g 3个浓度水平的回收率为90.0%-98.9%,相对标准偏差小于1.47%（n=6）,方法定量限为0.5μg/100 g。叶黄素储备液在-70℃冰箱中保存12个月内含量稳定。结论该方法快速、准确、灵敏,适合测定婴幼儿配方乳粉中叶黄素含量的检测,婴幼儿配方乳粉在储存过程中叶黄素含量有下降趋势,保质期内符合国家标准要求。

Objective To establish a detection method of lutein content in infant formula milk powder, confirm the period of validity of lutein standard reserve liquid, and study the storage stability of infant formula milk powder. Methods Samples were dissolved by ultra pure water and then extracted by 0.1% BHT-acetone solution with ultrasonic. Target compounds were separated on a reversed phase using methanol-methyl tert butyl, with the flow rate of 1.0 m L/min, sampling volume of 50 μL and column temperature of 25 ℃ by DAD detector. Detection wavelength was set at 445 nm. Results The target compound was completely separated and analyzed in 15 min. The recoveries were ranged from 90.0% to 98.9% with 3 spiked levels of 0.1, 1.0 and 10.0 μg/100 g. The relative standard deviations（RSDs） were less than 1.47%（n=6）, and the limits of quantitation（LOQ） were 0.5 μg/100 g. The shelf life of lutein standard solution was 12 months in-70 ℃refrigerator. Conclusion The proposed method is fast, accurate and sensitive, which is suitable for the detection of lutein content in infant formula milk powder. The content of lutein has decreased in the preservation process of infant formula milk powder.