Bioaccessibility of EPA and DHA in microencapsulated algae oil as affected by wall material and homogenisation techniques

The present work aims to elucidate the potential effect of emulsion homogenisation technique (high pressure (HP) vs. ultrasounds (US)) and wall material (a combination of polysaccharides, chitosan and maltodextrin (CM), vs. plant proteins, pea protein isolate (PP)) on the quality characteristics of omega-3-rich algae oil microcapsules and, in turn, on the bioaccessibility of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Both studied factors induced differences in most quality variables under study. Moreover, their interaction significantly influenced crucial microcapsule properties, including microencapsulation efficiency, omega-3 content and oxidative stability. Thus, CM microcapsules demonstrated a higher solubility and a lower external oil content than PP microcapsules. Conversely, PP microcapsules, especially HP homogenised ones, evidenced higher yields and oxidative stability. Additionally, PP-US exhibited higher bioaccessibility for both EPA and DHA, constituting the optimal combination for microencapsulating omega-3-rich algae oil. Algae oil microencapsulated with pea protein produced by ultrasound shows excellent EPA/DHA bioaccessibility while keeping high encapsulation efficiency and oxidative stability. • Ultrasound and high-pressure homogenization were compared for emulsion properties. • Algae oil was microencapsulated using plant-based protein and polysaccharide walls. • Chitosan-maltodextrin improve solubility and reduce external oil in microcapsules. • Wall material and homogenisation method have significant interactive effects. • Pea protein-ultrasound yield the highest stability and omega-3 bioaccessibility.