核磁共振磷谱法测定乳制品中的磷脂含量Analysis of phospholipids content in dairy products by 31P NMR

Abstract

为了测定乳制品中的磷脂含量，建立了基于核磁共振磷谱（31P NMR）的磷脂分析方法，并采用内标法对磷脂进行了定量。利用建立的方法对不同哺乳期母乳（初乳、过渡乳、成熟乳）、奶粉（全脂奶粉、婴幼儿配方奶粉）、富含乳磷脂的乳清蛋白粉、大豆磷脂及鸡蛋磷脂中的磷脂组成及含量进行了分析。结果表明：9种磷脂标准品的检出限范围为48.97~85.76 μg/mL，定量限范围为97.94~171.52 μg/mL，具有合理的加标回收率（83.40%~108.52%）和精密度（相对标准偏差小于15%）。母乳中总磷脂含量平均为19.27 mg/100 mL，随着哺乳期的延长总磷脂含量逐渐降低。不同来源的样品中磷脂的组成有较大差异，母乳中含量最高的磷脂类型为鞘磷脂，其他样品中的磷脂主要类型为磷脂酰胆碱。 In order to determine the content of phospholipids in dairy products, a method for the determination of phospholipid was established based on 31P NMR and the internal standard method was used to quantify the phospholipid. The composition and content of phospholipid in different lactation human milk (colostrum milk, transitional milk, mature milk), milk powder (whole milk powder, infant formula milk powder), whey protein powder rich in lacto-phospholipid, soybean lecithin and egg lecithin were analyzed by this method. The results showed that the limits of detection and quantification of 9 phospholipid standards were 48.97-85.76 μg/mL and 97.94-171.52 μg/mL, respectively. They also demonstrated reasonable recoveries (83.40%-108.52%) and precision (relative standard deviation < 15%). The average total phospholipid content in human milk was 19.27 mg/100 mL, and it decreased gradually with the extension of the lactation period. The composition of phospholipid varied greatly among samples from different sources. Sphingomyelin was the most abundant type in human milk, while phosphatidylcholine was the main type in other samples.

Keywords

• 31p nmr；母乳脂肪；婴幼儿配方奶粉；磷脂；乳脂肪球膜
• 31 p nmr；human milk fat；infant formula milk powder；phospholipid；milk fat globule membrane