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.