Controlled release of alginate-encapsulated Thymus vulgaris essential oil and its phenolic compounds enhances the oxidative stability of Arbequina olive oil

Abstract

Abstract This study aimed to investigate the oxidative stability of Arbequina olive oil enriched with Thymus vulgaris essential oil encapsulated in calcium alginate capsules. Oxidation in the control oil was greatly accelerated, as confirmed by the peroxide value, from 1.5 ± 0.07 to 47 ± 1.41 meq O 2 /Kg. However, the peroxide value of the encapsulated oil was considerably lower, only reaching 20.5 ± 2.12 meq O 2 /Kg. This demonstrates the effectiveness of encapsulation in enhancing oxidative stability. Moreover, the encapsulated oil showed a significantly lower malondialdehyde value (0.223 mg/Kg), showing the efficacy of the method in reducing oxidation. Rancimat analysis also confirmed the protective role of encapsulation. Induction times were recorded as 0.085 h for the control oil, 9.46 h for Thyme-EO@Alg, 15.06 h for Thymol@Alg, 14.45 h for γ-terpinene@Alg, and 13.40 h for Carvacrol@Alg. All these results showed that alginate-based encapsulation is an effective method for improving the oxidative stability of Arbequina olive oil.