LAUSR

Abstract The present study aimed to characterize the surface properties of Nile tilapia (Oreochromis niloticus) fillets and evaluate the wettability properties of edible coatings based on chitosan and gelatin from fish scales on its surface using varying concentrations of biopolymers and plasticizer. The surface of Nile tilapia fillet was characterized as low-energy with a surface tension of 63.80 mN/m, whose polar and dispersive components were 49.98 mN/m and 13.82 mN/m, respectively. From the 32 experimental design it was observed that the increase of the chitosan concentration leads to higher values of the adhesion coefficient but results on a decrease of the spreading coefficient. For gelatin coatings, the biopolymer concentration was found to both decrease the adhesion and spreading coefficients. However, the use of higher plasticizer concentrations decreased the values of adhesion and spreading coefficients for the chitosan coatings while increases the values for the gelatin coatings. Preliminary characterization revealed that the best experimental spreadability coefficients (Ws) were −13.565 mN/m for the chitosan coatings and −10.762 mN/m for gelatin coatings.