嬰兒配方食品中牛乳鐵蛋白檢驗方法開發   全文下載

Method Development of Bovine Lactoferrin Analysis in Infant Formula

乳鐵蛋白為一種含鐵醣蛋白，分子量約為80 kDa，廣泛存在於哺乳動物之乳汁中。為配合衛生福利部111年3月10日修正「食品添加物使用範圍及限量暨規格標準」有關乳鐵蛋白「可使用於標示有每日食用限量之食品，在每日食用量中，其總量不得高於300 mg」及「本品可於特殊營養食品中視實際需要適量使用」規定，開發嬰兒配方食品中牛乳鐵蛋白檢驗方法。將樣品中牛乳鐵蛋白以二硫蘇糖醇（Dithiothreitol）及碘乙醯胺（Iodoacetamide）分別進行還原及烷化，再以胰蛋白酶（Trypsin）水解後，以超高效液相層析串聯質譜儀（Ultra Performance Liquid Chromatograph/tandem Mass Spectrometer, UPLC-MS/MS）進行分析。以不含牛乳鐵蛋白之駝乳營養粉作為空白基質進行5重複添加回收試驗結果，添加4、10及40 mg/100g乳鐵蛋白之同日間平均回收率分別為91.0、95.1及105.7%，變異係數分別為6.7、3.2及6.6%；異日間平均回收率分別為93.0、99.4及112.2%，變異係數分別為7.8、7.8及7.4%；定量極限為4 mg/100 g。市售產品之檢驗方法適用性評估結果，3件具乳鐵蛋白標示之產品，其牛乳鐵蛋白含量為120-253 mg/100 g；1件水解蛋白基質產品及2件羊奶基質產品則均未檢出牛乳鐵蛋白。

Lactoferrin is an iron-binding glycoprotein commonly found in mammalian milk. To comply with the amended“Standards for Specification, Scope, Application and Limitation of Food Additives”announced by the Ministry of Health and Welfare of March 10, 2022, which stipulates that“Lactoferrin can be used in foods labeled with daily intake limits, and the total daily intake should not exceed 300 mg”and“This product can be used in special nutritional foods as needed”. A test method for bovine lactoferrin in infant formula products was developed. The protocol in brief was that bovine lactoferrin was reduced by dithiothreitol, alkylated by iodoacetamide, hydrolyzed by trypsin, and then analyzed by an ultra-high performance liquid chromatography/tandem mass spectrometer (UPLC-MS/MS). The average recoveries of bovine lactoferrin spiked at 4, 10 and 40 mg/100 g into the blank matrix made of camel milk nutrition powder were 91.0, 95.1 and 105.7%, and the coefficients of variance were 6.7, 3.2 and 6.6%, respectively in intra-day test (n=5); the average recoveries were 93.0, 99.4 and 112.2%, and the coefficients of variance were 7.8, 7.8 and 7.4%, respectively in inter-day test (n=10). We tested commercial nutrition supplement products for the application of the testing method, the results showed the detected values of bovine lactoferrin in 3 commercial products with bovine lactoferrin labeling were in the range of 120-253 mg/100 g. One hydrolyzed formula powder and 2 commercial products constituted of goat milk were not detected of bovine lactoferrin.