Abstract: The volatile flavor components of three different Mozzarella cheeses (fresh buffalo milk cheese, fresh cow milk cheese and semi-hard cow milk cheese) were identified by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). By gas chromatography-olfactometry (GC-O), a total of 109 compounds were determined in the cheese samples and semi-quantified by GC-MS. The odor activity values (OAV) of 31 compounds were calculated and analyzed by principal component analysis (PCA). Results showed that the major volatile compounds in fresh buffalo milk Mozzarella cheese were hexanal, heptanal, ethyl caproate, (E)-2-nonene aldehyde, furfural and ethyl butyrate. The main volatile flavor substances of fresh bovine milk Mozzarella cheese were 1-octene-3-alcohol, 2-undecanone and δ-dodecalactone. The main volatile flavor substances of semi-hard Mozzarella cheese were n-decanoic acid phenylacetaldehyde and ethyl acetate. According to the PCA results, six Mozzarella samples could be divided into three categories, which indicated that these key aroma compounds could clearly explain the flavor differences among the 3 kinds of Mozzarella cheese. This study provides theoretical guidance for the identification of buffalo milk adulteration in Mozzarella cheese.

Key words: Mozzarella cheese; volatile compounds; solid-phase microextraction; principal component analysis