Functional Olive Oil Production via Emulsions: Evaluation of Phenolic Encapsulation Efficiency, Storage Stability, and Bioavailability

Background/Objectives: Olive oil is valued for its health benefits, largely due to its bioactive compounds, including hydroxytyrosol (HTyr) and oleuropein (OLE), which have antioxidant, anti-inflammatory, and cardioprotective properties. However, many of these compounds are lost during the production process. This study developed a functional olive oil-derived product using water-in-oil emulsions (W/O) to incorporate commercial extracts rich in HTyr and OLE. Methods: HTyr and OLE were encapsulated in a W/O emulsion to preserve their bioactivity. The encapsulation efficiency (EE) was evaluated, and the performance of the emulsion was tested using an in vitro gastrointestinal digestion model. Bioaccessibility was measured by calculating the recovery percentage of HTyr and OLE during the digestion stages. Results: The results showed that OLE exhibited higher EE (88%) than HTyr (65%). During digestion, HTyr exhibited a gradual and controlled release, with bioaccessibility exceeding 80% in the gastric phase and a maintained stability throughout the intestinal phase. In contrast, OLE displayed high bioaccessibility in the gastric phase but experienced a notable decrease during the intestinal phase. Overall, the W/O emulsion provided superior protection and stability for both compounds, particularly for the secoiridoids, compared to the non-emulsified oil. Conclusions: The W/O emulsion improved the encapsulation and bioaccessibility of HTyr and OLE, constituting a promising method for enriching olive oil with bioactive phenolic compounds. Therefore, this method could enhance olive oil’s health benefits by increasing the availability of these bioactive compounds during digestion, offering the potential for the development of fortified foods.