Isolation and identification of headspace volatiles formed in heated butter

Unsalted sweet butter was heated at 100, 150, or 200 degrees C for 5 h. The headspace volatiles formed were collected during heating using a simultaneous purging and solvent extraction apparatus. Among 140 peaks on a gas chromatogram of the headspace sample from butter heated at 200 degrees C, 77 were positively identified by gas chromatography and gas chromatography/mass spectrometry. Major compounds identified were 21 aldehydes, 12 fatty acids, 11 ketones, 10 nitrogen- and/or sulfur-containing compounds, 7 alkanes, 6 delta-lactones, and 4 furans, which constituted over 85% of total volatiles recovered. The number of volatiles formed in a headspace of butter heated at 100 or 150 degrees C was much less than that formed at 200 degrees C. However, all volatiles formed at 100 and 150 degrees C were found in a sample heated at 200 degrees C