傅里叶变换红外光谱法分析乳制品的成分

利用甲醇沉淀进口奶粉、国产奶粉和奶茶粉水溶液中的蛋白质,所得上清液用二氯甲烷萃取,再经傅里叶变换红外光谱法(FT-IR)分析沉淀物和各相中物质的成分.试验结果表明:3种样品沉淀物中均含有蛋白质和脂肪酸甘油三酯,在萃取时均有乳糖析出.三者上层(水+甲醇)均含有糊精;而下层(二氯甲烷-甲醇)进口奶粉中含有磷脂酰胆碱,国产奶粉中含有磷脂酰胆碱和长碳链伯酰胺,奶茶粉中含有咖啡因.

Analysis of Ingredients of Milk Product Via FTIR Spectrosmetry

Proteins in imported milk powder, China-made milk powder and milk tea powder were precipitated via the addition of methanol.The supernatant was extracted by dichloromethane. Then the components of precipitates and substance in the two phases were analysised by Fourier transform infrared spectrometry (FT-IR). Reasults were as follows: Precipitates of the powders contained proteins and triglyceride. Lactose was separated out during the extraction. The upper layer(mixture of water and methanol)of the powders contained dextrin. The lower layer(mixture of dichloromethane and methanol) of the imported milk powder contained phosphatidylcholine, while that of the China-made milk powder contained phosphatidylcholine and long carbon chain amide, and that of the milk tea powder contained caffeine.