Biopolymer-coated nanoliposomes as carriers of rainbow trout skin-derived antioxidant peptides

•Fish skin-derived antioxidant peptides were encapsulated in polymer-coated liposomes.•FTIR spectra revealed interactions between phospholipids and biopolymer chains.•Chitosan coating up to 0.4% favored the peptide encapsulating efficiency of liposomes.•Encapsulation retained the antioxidant activity of the gelatin peptide fraction.•Sustained in vitro release of bioactive peptide was improved by chitosan coating.

In this study, an antioxidant peptide fraction with a molecular mass < 30 kDa (PF30) isolated from rainbow trout (Oncorhynchus mykiss) skin gelatin hydrolysates was encapsulated in chitosan-coated nanoliposomes. The mean particle size of liposomal nanovesicles containing PF30 was found to be in the range 163.4-234 nm with a low polydispersity index (PDI < 0.5); furthermore, the ζ-potential changed from +3.9 mV in uncoated liposomes to +45.5 mV in biopolymer-coated liposomes. FTIR spectra showed electrostatic interactions as well as hydrogen bonding between phospholipid head groups and amine groups of chitosan. The entrapment efficiency of PF30 (2 mg/ml) was found to be highest in nanoliposomes coated with 0.4% (w/v) chitosan. Biopolymer-coated liposomes demonstrated more sustained peptide release behavior in vitro. Moreover, the chitosan-coated nanoliposomes maintained the antioxidant activity of the PF30 and could be considered a potential candidate for efficient delivery of bioactive compounds in nutraceutical and functional foods.