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.