Monitoring of autoxidation in LCPUFA-enriched lipid microparticles by electronic nose and SPME-GCMS

Electronic nose and SPME-GCMS were used to monitor the autoxidation in long chain polyunsaturated fatty acid (LCPUFA)-enriched lipid microparticles produced by spray congealing with ultrasonic nebulization, during storage at 20 °C up to 6 weeks with sufficient air supply and limited air supply. Conjugated dienes and peroxide value as well as secondary lipid oxidation products were analysed to follow the course of autoxidation. Principal Component Analysis evidenced that only MOS sensors but not MOSFET sensors contributed to the discrimination of the samples and facilitated the ability of the electronic nose to distinguish the LCPUFA-enriched lipid microparticles into two groups according to the different oxidative status. The selected MOS sensor responses correlated well with quantitative dominating volatile compounds (propanal and hexanal) and with volatile compounds which have been associated with fishy and rancid off flavour (1-penten-3-one, 1-penten-3-ol, 2,4-heptadienal and 2,6-nonadienal). Bread mix supplemented with the LCPUFA-enriched microparticles was analysed as an example for a LCPUFA supplemented food. Data from the present study indicate that the electronic nose can be used as a sensitive tool to evaluate the lipid oxidative status of LCPUFA-enriched microparticles. In supplemented foods like bread mix, matrix-related changes, which occur in supplemented and non-supplemented samples, make a clear distinction more difficult.