Use of residual lipid fractions and protein hydrolysates from salmon skin cleaning processing for liposome production and their application in Pickering emulsions

In the salmon skin and scale cleaning process, several lipid fractions and protein materials were recovered as secondary by-products, presenting opportunities for the production of bioactive ingredients with high nutritional value. The predominant lipid component in all oil fractions was oleic acid. A protein hydrolysate was also obtained, consisting of ≈27% essential and ≈60% hydrophobic amino acids, below 3KDa (≈90.2%), and with significant antioxidant, ACE inhibitory and antidiabetic properties. Hydrolysate-loaded Liposomes (LH), prepared from partially purified phospholipids from recovered lipids, exhibited a slightly larger mean size (283 nm) than empty liposomes (226 nm) (L), and a very stable ζ potential for both. Stable oil-in-water emulsions (30/70) were produced using the oil fraction and replacing the aqueous phase by a dispersion of empty liposomes or hydrolysate-loaded liposomes. The presence of free or encapsulated hydrolysate resulted in poorer stabilisation compared to the empty liposomes, demonstrating that the latter are good Pickering agents.