Acetone as Indicator of Lipid Oxidation in Stored Margarine

Margarine contains a minimum of 80% fat and is therefore prone to lipid oxidation. While lipid oxidation in vegetable oils and <i>o</i>/<i>w</i> emulsions has been thoroughly investigated, studies about the oxidative stability and the identification of potential indicators of lipid oxidation in margarine are scarce. To evaluate the oxidative stability and to indicate the progress of lipid oxidation, four different types of industrial margarine (M1–M4), which differed in their composition of the minor ingredients and the oil phase, were stored at 15 °C for 180 days and analyzed at days 0, 1, 7, 14, 28, 56, 99, and 180 regarding peroxides, conjugated dienes, oxidized triacylglycerols, and volatiles. The peroxide value and the conjugated dienes increased up to 4.76 ± 0.92 meq O₂/kg oil and 14.7 ± 0.49 in M2, respectively. The oxidative stability decreased by a maximum of 50.9% in M4. We detected three different epoxidized triglycerides—TAG54:1 (O), TAG54:2 (O) and TAG54:3 (O)—in M3. Acetone could be identified, for the first time, as lipid oxidation product in stored margarine by headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). It increased in all types of margarine during storage by a maximum of 1070 ppb in M2. Acetone might be used as a new indicator for lipid oxidation in margarine.