Study of the effect of the chitosan use on the properties of biodegradable films of myofibrillar proteins of fish residues using response surface methodology

This study aimed to determine the optimal formulation to prepare biodegradable myofibrillar protein films from fish residues, chitosan, and glycerol using the response surface methodology. The myofibrillar proteins (MP) were extracted from filleting residues of gilthead bream (Brachyplatystoma roussauxii). A full factorial design was employed to assess three independent variables (MP, chitosan, and plasticizer concentrations) and three dependent variables (tensile strength, elongation, and water vapor permeability). The experimental design results indicated the best conditions to prepare the film were 1.3% (m/v) MP, 30% (m/m) chitosan, and 40% glycerol (m/m). The control film was prepared with 1.3% (m/v) MP and 40% glycerol (m/m). Adding chitosan increased the viscosity of the solution and the elongation, but reduced solubility and swelling by 66,43% and 74,56%, respectively. The optimized film tended to have an opaque structure with excellent UV-barrier properties. It also had good thermal stability and dense structure, indicating chitosan is able to enhance the properties of fish myofibrillar protein films.