Abstract: Milk fat is central to the sensory experience of dairy and bakery products. Many kinds of volatile compounds are found in milk fat, whereas only a small number of key flavor compounds have significant contribution to its whole flavor. In this study, solid phase microextraction coupled with gas chromatography - mass was used to investigate the volatile compound profiles of 8 milk fat products (including 4 butters, 2 creams and 2 cultured butters) popular on the Chinese market. Then key flavor compounds of milk fat were analyzed by both relative odor activity value (ROAV) and gas chromatography - olfactometry (GC-O). The results showed that 40 kinds of volatiles were found in the eight milk fat products. 17 kinds of volatiles were identified as key flavor compounds using ROAV, and GC-O identified 7 kinds of key flavor compounds. Acetic acid, butanoic acid, hexanoic acid, δ-octanolactone, δ-decanolactone and γ-dodecalactone appeared to be the most significant flavor compounds in milk fat, which were identified by both ROAV and GC-O.

Key words: milk fat, solid - phase microextraction, relative odor activity value, olfactometry, key flavor compounds