Abstract: Gas chromatography-ion mobility spectrometry (GC-IMS) was used to analyze the volatile flavor compounds different dairy products, including two brands of pasteurized milk, five brands of ultra-high-temperature sterilized milk and one brand of reconstituted milk. A total of 29 compounds were identified, mainly aldehydes, ketones, alcohols, esters, and others. Methyl hexanoate, ethyl butanoate, 3-methylbutyl acetate, ethyl acetate, ethyl pentanoate, 1-pentanol, and limonene constituted the characteristic peak region of pasteurized milk; furfural, benzaldehyde, methyl isobutyl ketone, 2-octanone, 1-butanol, and isopropyl acetate constituted the characteristic peak region of reconstituted milk; and new volatile compounds generated by sterilization constituted the characteristic peak region of ultra-high-temperature sterilized milk. By means of principal component analysis (PCA), the different types or brands of dairy products were clearly classified. This study indicates the usefulness of GC-IMS to discriminate different dairy products.

Key words: gas chromatography-ion mobility spectrometry; dairy products; volatile flavor compounds; discrimination