Lipid oxidation and flavor changes in saturated and unsaturated fat fractions from chicken fat during a thermal process

Chicken fat, due to its rich fatty acids (FAs), is more prone to lipid oxidation and the production of volatile compounds. The aim of the present study was to investigate the oxidative characteristics and flavor changes of saturated (SFF) and unsaturated fat fractions (USFF) from chicken fat induced by heating (140 °C at 70 rpm min-1 for 1 h and 2 h: SFF1, USFF1, SFF2 and USFF2). The FAs and volatile compounds were analyzed by gas chromatography-mass spectrometry (GC-MS) and two-dimensional gas chromatography time of flight mass spectrometry (GC × GC-ToFMS), respectively. The results showed that higher contents of unsaturated fatty acids (UFAs) were found in USFF compared to that in SFF, whereas USFF showed lower levels of saturated fatty acids (SFAs). With the extension of heating time, the SFA/UFA ratio in USFF and SFF significantly increased (p p Z)-3-hexenal, (E)-2-decenal, 2-undecenal, (E)-2-dodecenal, (E,E)-2,4-nonadienal, (E,E)-2,4-decadienal, 2-decanone, γ-octalactone and γ-nonalactone. Our data elucidated that fat fractions from chicken fat with varying degrees of saturation could impart different flavor characteristics during a thermal process.