Impact of interactions between whey protein isolate and different phospholipids on the properties of krill oil emulsions: A consideration for functional lipids efficient delivery

The interactions between different phospholipids (yolk phospholipid, soybean phospholipid, and perilla seed phospholipid) and whey protein isolate (WPI) were studied. Physical characteristics and bioaccessibility of different emulsions were compared. According to the results of multiple spectroscopy, isothermal titration calorimetry (ITC), and molecular docking, hydrophobic interactions played an important role in the interaction of phospholipid and WPI, enhanced as more unsaturation. Dynamic light scattering showed that combination of phospholipids and proteins could decrease particle sizes (from 232.33 ± 4.79 nm to 188.59 ± 2.61 nm) and improve emulsion stability significantly (from −34.26 ± 1.31 mV to −49.13 ± 1.91 mV), presenting dose-dependency. Microstructure results indicated that phospholipids would contribute to dispersity and homogeneity of emulsions. Furthermore, the phospholipid-WPI emulsion can be an efficient tool for functional lipid delivery and improving the functional lipid ratios in the zebrafish model. Compared to WPI emulsions, the phospholipid-WPI emulsion group exhibited higher ratios of functional lipids in zebrafish fatty acid compositions (up to 29.41% ± 0.87%). In vitro digestion supported that perilla seed phospholipid-WPI emulsions would contribute to a higher bioaccessibility of EPA (from 36.59% ± 0.88%–53.08% ± 0.96%), DHA (from 36.42% ± 1.03%–54.10% ± 1.07%) and astaxanthin (from 31.54% ± 2.52%–53.31% ± 4.05%). Overall, our research can be useful to an efficient delivery system for functional lipids with phospholipid-protein structures.