膠錠保健食品中葉酸檢驗方法之探討   全文下載

Investigation of the Analytical Method for Folic Acid Quantification in Functional Foods in Capsule or Tablet Form

參照衛生福利部食品藥物管理署（下稱食藥署）之「膠囊與錠狀食品中水溶性維生素之檢驗方法」，以酸性液萃取葉酸進行檢測，發現於部分產品中葉酸含量偏低。為瞭解pH值對檢測膠錠食品中葉酸含量之差異，將葉酸標準原液分別調製成酸性（pH2.5）與鹼性（pH 9.0）之2系列標準溶液，經液相層析儀分析結果，所得之標準曲線之線性關係均良好。此外，5件市售錠狀產品以鹼性液萃取所得葉酸之檢測值為其標示值之89-108%；而於酸性液萃取之檢測結果，3件含葉酸之綜合型維生素產品之檢測值分別為其標示值之112、83及22%，另2件以葉酸為單一成分之產品，其檢測值均低於方法定量極限（0.025 mg/g），顯示葉酸經鹼性液萃取分析之回收率較佳，而於酸性液萃取環境下，產品中抗氧化成分之存在，具有保護葉酸安定性之效果。當檢體為僅含葉酸之膠錠食品，或對產品中葉酸含量檢驗結果有疑義時，應使用鹼性液配製標準溶液及進行檢體之萃取，以確保葉酸檢驗結果之正確性。上開說明已加註於修正之檢驗方法中並於110年10月1日公開於食藥署網站供大眾參考。

Some products showed lower folic acid content than labeled using the acidic extraction method (Method of Test for Water-Soluble Vitamins in Foods in Capsules or Tablets Forms) published by the TFDA, therefore, the effect of pH on the detection of folic acid content in foods in capsule or tablet form was studied. The linear regressions of the folic acid standard curve were good using high performance liquid chromatography (HPLC), regardless of the standard stock solution was diluted with acidic (pH 2.5) or alkaline solution (pH 9.0). Five products labeled with folic acid were investigated. With alkaline extraction, the ratios of the amounts of folic acid detected to those labeled in 5 samples in tablet form were in the range of 89-108%; with acidic extraction, the ratios of the amounts of folic acid detected to those labeled in 3 samples labeled as multivitamin tablets were 112%, 83% and 22%, respectively, while the amounts of folic acid detected in the other 2 samples labeled as single folic acid ingredient tablets were lower than the limit of quantification (0.025 mg/g). It was indicated that recoveries of folic acid by the alkaline extraction solution were higher than those by the acidic extraction solution. However, the presence of antioxidant components in the samples could protect the stability of folic acid in the acidic extraction solution. The alkaline solution should be used as the diluent for the standard solution and the extraction solvent of the sample to ensure the accuracy of the results if the sample contains only folic acid ingredient or there is any doubt about the analytical results of folic acid in the product. The above description has been annotated in the amended recommended method which was published on the TFDA website on October 1, 2021.