微生物法测定婴幼儿配方乳粉中叶酸的超声提取条件优化

Optimization of ultrasound-assisted extraction for folic acid in infant formula milk powder by microbiological method

中文关键词:  叶酸  响应面法  微生物法  超声提取法

英文关键词:folic acid  response surface methodology  microbiological method  ultrasound-assisted extraction

中文摘要:

      目的 通过响应面法优化微生物法测定婴幼儿配方乳粉中叶酸的超声提取条件。方法 以超声温度、超声时间、样品中叶酸含量和提取液pH为研究对象, 通过Plackett-Burman试验、最陡上升路径法和Box-Benhnken试验进行响应面分析。结果 经响应面法优化后, 对超声提取影响最显著的3个因素及最佳提取条件为: 超声温度32 ℃、超声时间135 min、样品中叶酸含量657 ng。在此条件下, 验证试验测得样品中叶酸含量均值为148.12 μg/100 g, 标准差为1.39 μg/100 g, 与预测值和样品特性值基本一致。对市售17个样品分别用最佳提取条件和国标提取条件测定, 最佳提取条件测定结果平均提高13.7%。结论 优化后条件显著提升了微生物法检测叶酸的准确性和实验室间一致性, 有效消除了国标法的系统误差, 为保障婴幼儿配方乳粉营养标签的真实性提供了可靠的技术依据。

英文摘要:

      Objective To optimize the ultrasound-assisted extraction conditions for folic acid in infant formula via the microbiological method using response surface methodology. Methods Taking ultrasonic temperature, ultrasonic duration, folic acid content in the sample, and pH of the extraction solvent as research objects, response surface analysis was conducted through Plackett-Burman design, the steepest ascent path method, and Box-Behnken design. Results The 3 most significant factors influencing ultrasonic extraction and the optimal extraction conditions were: Ultrasonic temperature of 32 ℃, extraction time of 135 min, and sample folic acid content of 657 ng. Under these conditions, validation tests yielded a mean folic acid content of 148.12 μg/100 g with a standard deviation of 1.39 μg/100 g, aligning closely with predicted values and sample specifications. The 17 commercially available samples were analyzed using both optimal and national standard extraction conditions. The results demonstrated an average improvement of 13.7% with the optimal extraction protocol compared to the national standard method. Conclusion Under the optimized conditions, the accuracy and inter-laboratory consistency of folic acid determination by the microbiological method are significantly improved, effectively eliminating the systematic errors associate with the national standard method. This provides a reliable technical basis for ensuring the authenticity of nutrition labeling in infant formula.