Encapsulation of tuna oil by liquid and solid self‐emulsifying delivery system: in vitro digestion and oxidative stability assessment

Abstract

SummaryTuna oil, one of the main sources of omega‐3 polyunsaturated fatty acids (omega‐3 or n‐3 PUFAs), is known to have limited bioavailability due to its hydrophobicity. Moreover, the main n‐3 PUFAs found in tuna oil, that is docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are prone to oxidation. To overcome these drawbacks, tuna oil encapsulation via liquid (LSEDS) and solid self‐emulsifying delivery system (SSEDS) was developed. Different LSEDS formulations were prepared and evaluated in terms of tuna oil droplet size and dispersibility. Accordingly, the formulation with small droplets size and narrow size distribution was selected and further developed into SSEDS by spray drying process. SSEDS was thereafter characterised concerning production yield, moisture content, size, size distribution and morphology. Furthermore, the in vitro simulated gastrointestinal model of LSEDS and SSEDS was carried out. The results showed that after intestinal digestion stage, 87% and 72% of DHA were released from LSEDS and SSEDS, respectively. Therefore, these formulations of LSEDS and SSEDS were proven their ability to enhance the bioaccessibility of DHA. Moreover, the oxidative stability of LSEDS and SSEDS formulation was investigated and compared to pure tuna oil using non‐isothermal differential scanning calorimetry (DSC) analysis under oxygen. The results showed that both LSEDS and SSEDS formulations exhibited a high oxidative resistance with a higher energy needed to induce tuna oil oxidation than pure tuna oil. The chemical and thermal stability given by LSEDS and SSEDS may be efficiently applied in food area to enhance the techno‐functional properties of hydrophobic compounds.