Natural SilibininLinoleate: A Protective Antioxidant in Edible Vegetable Oils

This study evaluated the potential of silibinin linoleate (SL), a natural derivative of silibinin, as an antioxidant to improve the thermal stability of sunflower oil (SF). SL was synthesized through green technology by enzymatic esterification, using mild reaction conditions. SL was added to high-oleic SF samples at three concentrations (200, 400, and 600 ppm), and the oils were subjected to heating at 180 °C for 4 and 8 h. Oxidative stability, fatty acid composition, and nutritional indices were analyzed. The results showed that 600 ppm SL provided the strongest antioxidant effect, significantly reducing oxidation parameters after 8 h of heating, in addition to the following values: peroxide value (PV) 14.22 ± 0.31 meq O₂/kg, p-anisidine value (p-AV) 22.85 ± 0.34, inhibition of oxidation (IO) 56.41 ± 0.31%, and total oxidation value (TOTOX) 51.30 ± 0.39. FTIR spectroscopy confirmed that SL effectively protected the triglyceride structure and limited the formation of oxidation by-products. SL demonstrated a protective effect against thermal oxidation in sunflower oil, with its efficacy being clearly dose-dependent. At 600 ppm, SL showed comparable or superior activity to BHT. However, this effect was specific to the highest tested concentration and does not indicate superiority across all concentrations. These findings suggest that SL has potential as a natural antioxidant for improving oil stability, but further studies are needed to validate SL as a practical and scalable alternative to synthetic antioxidants in the food industry.