Viscera of tilapia (Oreochromis spp.) were used for the production of a protein hydrolysate, which was characterized in terms of proximate composition, molecular weight distribution, amino acid composition and antioxidant activity (ABTS radical scavenging capacity, ferric ion reducing power (FRAP) and ion chelating activity). Liposomes from soy lecithin (SL), rapeseed lecithin (RL), and soy-rapeseed (SRL) lecithin blend (1:1, w/w) were prepared, showing average particle sizes of 153, 218 and 193 nm, respectively, and similar ζ potential of −46 mV. Rapeseed lecithin liposomes presented much higher antioxidant activity than with SL. Liposomes made of SRL, having intermediate hydrodynamic and antioxidant properties than the other two, were selected to encapsulate the tilapia hydrolysate at different concentrations (5, 10 and 20 g/100 g, with respect to lecithin). Liposomes loaded with 20 g/100 g of hydrolysate (SRLH20) had smaller particle size and higher ABTS values and iron chelating activity, while liposomes loaded with 5 g/100 g (SRLH5) had higher electronegative ζ potential and entrapment efficiency, which was calculated as a function of total protein content, antioxidant capacity and individual amino acid residues. Charged amino acid residues and alanine were highly entrapped in both SRLH5 and SRLH20. No clear preference for encapsulating hydrophobic or hydrophilic amino acids was observed.

The authors are grateful for the financial support provided by Comité para el Desarrollo de la Investigación en la Universidad de Antioquia, Colombia through sustainability program 2018–2019, COLCIENCIAS (Project Code 111574558746) and by Agencia Estatal de Investigación (AEI), Spain and Fondo Europeo de Desarrollo Regional (FEDER), EU, through project NANOALIVAL AGL2017-84161.

Peer reviewed