Abstract:

Supercritical CO2 fluid was used to extract volatile flavor compounds from an artificially oxidized mutton fat (peroxide value, 197 mmol oxygen/ kg fat; and acid value, 3.90 mg KOH/kg fat). The influences of extraction temperature, pressure and time on appearance and odor characteristics and yield of extract were evaluated. The optimal technological parameters were determined as follows: extraction vessel at 20 MPa and 45 ℃, separation vessel I at 4.8 MPa and 20 ℃, separation vessel II at 4.8 MPa and 20 ℃, CO2 flow rate 45 L/h, and extraction duration 1 h. Correlation analysis between GC-MS and GC-O analytical results with retention time revealed that the characteristic odor of oxidized mutton fat was due to aldehydes and carboxylic acids, of which 6 short-chain fatty aldehydes including (E)-2-hexenal, (Z)-2-heptenal, (E)-2-octenal, decanal, (E)-2-decenal and (E, E)- 2, 4-decadienal, and three short-chain fatty acids including heptanoic acid, nonanoic acid and decanoic acid, were considered as key odorants contributing to odor of oxidized mutton fat.

Key words: oxidized mutton fat, supercritical CO2 fluid extraction, flavor compound, fatty aldehyde, fatty acid