摘要
目的:建立奶粉中A2β-酪蛋白分离定量的液相色谱-高分辨串联质谱法,并利用婴儿配方奶粉中酪蛋白、乳清蛋白和总蛋白含量的关系,间接得到乳清蛋白含量。方法:样品经前处理后,采用ACQUITY UPLC HSS T_(3)柱(100 mm×2.1 mm×1.8μm),0.1%甲酸-水和乙腈为流动相,梯度洗脱分离。多反应离子监测模式定量测定其中的A2β-酪蛋白特征肽。结果:在0.02~2.0μmol/L范围内线性关系良好(r=0.9938)。在低、中、高三水平加标试验中,回收率在94.9%~98.7%,相对标准偏差在1.7%~3.7%,检出限为0.80 mg/100 g,可满足对奶粉中A2β-酪蛋白定量要求。采用该法对市售11批声称A2奶粉和18批未声称A2奶粉(以下简称A2奶粉和普通奶粉)中A2β-酪蛋白进行测定。结论:A2奶粉中A2β-酪蛋白占总β-酪蛋白含量的86.2%~98.7%,而普通奶粉则低至20.0%~50.0%。另外,乳清蛋白含量的间接测定值和理论计算值经统计分析,无明显差异(P>0.05),为分析婴儿配方奶粉中乳清蛋白含量是否符合国标要求提供参考。
【Objective】A new and sensitive method was developed for the determination of A2β-casein in milk powder by liquid chromatography high resolution tandem mass spectrometry(LC-HRMS/MS).Then based on the relationship among casein,whey protein and total protein in infant formula,whey protein content was obtained indirectly.【Method】A2β-casein was separated on an ACQUITY UPLC HSS T_(3) column(100 mm×2.1 mm×1.8μm),and 0.1%(V:V)formate-water and acetonitrile were used as the flow phase for gradient elution and separation.The ntent of A2β-casein in milk powder was calculated by multi reaction ion monitoring mode.【Result】A good linearity with r=0.9938 was achieved within the range from 0.02—2.0μmol/L.Satisfactory recovery(94.9%—98.7%),relative standard deviation(1.7%~3.7%)and the detection limit(0.80 mg/100 g)were obtained at three levels,which could meet the quantitative requirements of A2β-casein in milk powder.The contents of A2β-casein in A2 milk powder(11 batches)and common milk powder(18 batches)were measured by this method.【Conclusion】The content of A2β-casein was 86.2%—98.7%and 20.0%—50.0%respectively.Moreover,there was no significant difference(P>0.05)between the indirect determination value and the theoretical calculation value of whey protein content,which provided reference for the test of whey protein content in infant formula whether met the requirements of national standard or not.
作者
刘彤彤
房芳
罗娇依
曹进
孙姗姗
LIU Tong-tong;FANG Fang;LUO Jiao-yi;CAO Jin;SUN Shan-shan(National Institutes for Food and Drug Control,Beijing 100050,China;Zhejiang Grain and Oil Product Quality Inspection Center,Hangzhou 310000,China)
出处
《中国食物与营养》
2022年第4期33-37,共5页
Food and Nutrition in China
