The interest in plant sterols enriched foods has recently enhanced due to their healthy properties. The
influence of the unsaturation degree of different fatty acids methyl esters (FAME: stearate, oleate, linoletate
and linolenate) on a mixture of three plant sterols (PS: campesterol, stigmasterol and b-sitosterol)
was evaluated at 180 C for up to 180 min. Sterols degraded slower in the presence of unsaturated
FAME. Both PS and FAME degradation fit a first order kinetic model (R2 > 0.9). Maximum oxysterols concentrations
were achieved at 20 min in neat PS and 120 min in lipid mixtures and this maximum amount
decreased with increasing their unsaturation degree. In conclusion, the presence of FAME delayed PS
degradation and postponed oxysterols formation. This protective effect was further promoted by increasing
the unsaturation degree of FAME. This evidence could help industries to optimize the formulation of
sterol-enriched products, so that they could maintain their healthy properties during cooking or
processing.