Oxidative Stability of Edible Oils Improved by Gaultheria procumbens L. Essential Oil during Long-term Storage

The oxidative stability of edible oils is a key determinant of their shelf life and nutritional quality. Growing consumer demand for natural antioxidants has prompted research into plant-based additives capable of preventing lipid oxidation. Gaultheria procumbens L. essential oil (GEO), known for its phenolic-rich composition, may provide protective benefits when added to oil matrices. This study investigates the effect of GEO on the antioxidant capacity of selected edible oils during prolonged storage. This study investigated the effects of GEO supplementation on the total antioxidant capacity (TAC) of rapeseed, olive and grapeseed oils during 120 days of storage. The results showed that all three oils experienced a gradual decrease in TAC due to oxidative degradation over time. However, the addition of GEO consistently mitigated this decline, with the most significant antioxidant protection observed at 30 and 120 days of storage. In rapeseed oil, GEO significantly increased the TAC by 19.30% at 120 days. Olive oil enriched with GEO retained a significantly higher TAC at 120 days (loss reduced from 19.93% to 7.97%), while grapeseed oil showed the most stable antioxidant profile, including a significant increase in TAC of 13.78% at 120 days. The protective effects of GEO are attributed to its high content of phenolic compounds with radical scavenging properties. Differences in the oils' fatty acid profiles and intrinsic antioxidant levels influenced the extent of GEO's efficacy. The observed benefits of GEO supplementation highlight its promising potential as a natural preservative in food technology. Its ability to enhance oxidative stability without the use of synthetic additives is in line with current trends favouring clean label and plant-based solutions. Furthermore, the efficacy of GEO in different oil matrices suggests broad industrial applicability and opens avenues for future research into its use in emulsions, functional foods and nutraceutical formulations.