Evaluation of Surface Properties of Chitosan and Scale Gelatin Coatings on Shrimp Fillets (Litopenaeus vannamei)

This study aimed to evaluate the wettability of edible coatings based on chitosan or the gelatin of Nile tilapia (Oreochromis niloticus) scales on the surface of shrimp fillets (Litopenaeus vannamei) with glycerol as a plasticizer. Initially, the surface was characterized according to Zisman's methodology. The surface tension and dispersive and polar components of the shrimp fillet was 59.93 (low-energy surface), 14.14, and 45.79 mN/m, respectively. The mathematical modeling applied to experimental design 3(2) showed that the minimum concentration of biopolymers favored wettability, among other observations about the interactions between the components of the coatings and the surface of the shrimp fillet. The behavior of the plasticizer was influenced by the biopolymer; as the concentration of the plasticizer increased, the cohesion coefficient of chitosan coatings decreased, while the opposite effect was observed for gelatin coatings. The coating compositions with optimized wettability were 1.0% chitosan and 0% glycerol (W-s = -12.934 mN/m), and 1.0% gelatin and 0% glycerol (W-s = -5.588 mN/m).