Encapsulation of thyme essential oil (Thymus vulgaris) in chia mucilage (Salvia hispanica L.) and its application in fresh pork sausage

Abstract

This study evaluated the application of thyme essential oil (TEO) encapsulated in chia mucilage in meat sausages as a partial or total substitute for sodium nitrate and nitrite. We assessed three capsules produced with different concentrations of TEO (3.5 %, 7.5 %, and 10 %) in terms of encapsulation efficiency, antioxidant activity, thermal properties, morphology, and antimicrobial activity. Compared to the other concentrations, the 10 % TEO capsules demonstrated higher encapsulation efficiency (98.25 %), antioxidant activity (25.53 %), minimum inhibitory concentrations (0.028 for Escherichia coli and 0.34 for Staphylococcus aureus), thermal stability, and efficacy in inhibiting S. aureus. The oil concentration did not influence capsule yield. We evaluated the physicochemical and microbiological characteristics of different fresh pork sausage formulations: preservatives only (FC), half the concentration of preservatives with the addition of TEO (F1), TEO only (F2), and no preservatives or TEO (F3). The F2 formulation exhibited reduced acidity, peroxide index, and p-anisidine content compared to formulations F1 and F3. Formulations F1 and F2 showed an increased a* parameter (redness) during storage. The F2 formulation exerted microbiological control over coagulase-positive Staphylococcus, E. coli, mesophilic aerobic bacteria, and Salmonella. We concluded that chia mucilage-encapsulated thyme essential oil represents a promising substitute for nitrates and nitrites in meat products.

Keywords: Antimicrobial activity; Antioxidant activity; Encapsulation; Lyophilization; Meat products.