Time-Dependent Effects of Caraway Essential Oil on the Total Antioxidant Capacity of Rapeseed, Olive, and Grapeseed Oils

Abstract

The use of essential oils in food preservation supports innovation in food technology and the development of healthier and more sustainable foods for consumers. The incorporation of essential oils into edible oil formulations or food products can help to extend shelf life, improve sensory attributes, and maintain nutritional quality, thus contributing to the development of healthier and more sustainable food products. This study aimed to investigate the effects of commercial caraway essential oil (CEO) as an antioxidant on the total antioxidant capacity (TAC) of rapeseed, olive, and grapeseed oils during 120 days of storage. Commercial CEO was provided by the Polish essential oil producer (Etja, Elbląg, Poland). The rapeseed, olive, and grapeseed oil samples (5 mL) were incubated with 0.1 mL CEO (final concentration 20 μg/mL) at 25 °C for 240 days. This reaction mixture was gently shaken at fixed intervals during incubation at 25 °C. Samples were collected for analysis after 0, 8, 15, 30, 60, and 120 days of storage. The rapeseed, olive, and grapeseed oil samples without additives were used as control samples. These oils showed different responses to the addition of CEO at different time intervals, highlighting the importance of considering temporal dynamics when assessing antioxidant effects. The addition of CEO to rapeseed oil increased the TAC in rapeseed oil at 30 and 120 days of storage, while the addition of CEO to olive oil increased the TAC at 30 and 60 days of storage. The addition of the CEO increased the TAC in grapeseed oil at 7, 30, and 120 days of storage. Our results suggest that the addition of CEO did not increase the antioxidant capacity of rapeseed and olive oils, especially during the early stages of storage. However, this effect changed over time, indicating a time-dependent increase in antioxidant potency. Interestingly, grapeseed oil showed a sustained increase in TAC after the incorporation of CEO after 30 days of storage, suggesting a potential synergistic relationship between the two components that warrants further investigation. Further research is warranted to optimise antioxidant formulations, elucidate underlying mechanisms, and assess safety considerations for wider use in food preservation and other food industry applications.