β‐Apo‐8′‐Carotenoic acid and its esters in sunflower oil oxidation

The oxidation kinetics of sunflower oil (SO) and pure triacylglycerols of sunflower oil (TGSO) in the presence of different concentrations (0.0008–0.02%, 1.9–32.7×10 −5 M) of β‐apo‐8′‐carotenoic acid (CA), ethyl β‐apo‐8′‐carotenoate (EC), and β‐apo‐8′‐carotenoylglycerol (CG) were studied. The process was performed at high (kinetic regime) and low (diffusion regime) oxygen concentrations at room temperature and at 100°C and in the dark and in daylight. CA, EC, and CG were not antioxidants in TGSO systems. However, the carotenoid derivatives, especially CA, increased the stability of tocopherol‐containing SO at room temperature and in daylight. The stabilization effect was more evident in a kinetic regime of oxidation. The synergism between the carotenoids and tocopherols was characterized by the increase of the stabilization factor F and activity A. F and A were highest for CA ( F =1.2–5.5, A =2.4–78.6), followed by EC ( F =1.2–3.5, A =1.7–14.6) and CG ( F =1.1–2.1, A =1.6–5.5) in the kinetic regime for SO exposed to daylight at room temperature.