Pickering emulsion stabilized by salmon protein-fucoidan complex and its absorption promotion effect on astaxanthin

In this experiment, salmon protein-fucoidan complexes (SMP-FU) were used to stabilize Pickering emulsions encapsulating astaxanthin (AXT). The hydrophobic forces and hydrogen bonding between SMP and FU were revealed as the main interaction to form the SMP-FU complex. The addition of FU led to the increase of threephase contact angle from 51.3 degrees to 92.1 degrees, and the best hydrophilic-hydrophobic balance was achieved with 2 % FU. The emulsions stabilized by SMP-FU became more homogeneous and denser with the increase of FU concentration, and the smallest droplet size was obtained in the emulsion stabilized by SMP-FU(2 %), which exhibited good rheological properties and acceptable stabilities under the heating, strong ionic strength and extreme acid-base conditions. AXT loaded Pickering emulsion (PEAs) stabilized by SMP-FU (SMP-FU-PEAs) provided better protection for AXT and improved the AXT retention rate under different storage condition, and displayed better gastric acid stability and higher AXT release rate (60.57 %) and bioaccessibility index (71.52 %) in than SMP-PEAs during in vitro digestion. The Caco-2 cell assay and in vivo experiments revealed a significant increase in the uptake rate of AXT embedded in SMP-FU-PEAs, which provided a feasible way to subsequently promote the uptake and utilization of the active substance.