Effect of tomato (Solanum lycopersicum L.) lycopene-rich extract on the kinetics of rancidity and shelf-life of linseed (Linum usitatissimum L.) oil.

The effect of tomato lycopene-rich extract (TLE) addition on shelf-life of linseed oil was evaluated. Linseed oil was extracted by cold pressing and TLE by supercritical CO2. Linseed oils with and without TLE addition were characterized for moisture, color, refractive index, fatty acid composition and antioxidants. Adding TLE to 80 mg lycopene/kg oil improved linseed oil stability, showing the same induction time at 110 °C (by Rancimat) of control linseed oil with 200 mg/kg butylhydroxytoluene. The increase of free fatty acid, peroxide value, p-anisidine value, K232 and K268 at 40, 50, and 60 °C until 90 days followed first-order kinetics. Rancidity rate augmented with temperature. TLE addition slowed oil degradation without changing the mechanism since the Arrhenius lines were parallel. Mean Ea were respectively 38.2, 24.7, 38.0, 38.2, 41.5 kJ/mol. TLE addition increased linseed oil shelf-life by 31% (Rancimat) and by 42% (stability kinetics during storage).