Monitoring by 1H nuclear magnetic resonance of the changes in the composition of virgin linseed oil heated at frying temperature. Comparison with the evolution of other edible oils

► The degradation of virgin linseed oil at frying temperature was monitored by 1H NMR. ► A great number of composition parameters were determined throughout the heating. ► These were compared with that of sunflower and extra virgin olive oil. ► Linseed oil degrades the fastest but its content in aldehydes is the lowest. ► The main aldehydes formed, like in sunflower oil, were (E,E)-2,4-alkadienals.