The objective of this study was to evaluate the properties of nanocomposite biofilms based on Whitemouth croaker (Micropogonias furnieri) protein isolate with organophilic clays. Initially the croaker protein isolate (CPI) was obtained using the pH shifting process from by-products of croaker industrialization. A Box and Behnken experimental design was used to develop the films, with three levels of CPI (2, 3.5 and 5 g.100 g-1 solution), montmorilonite MMT clay (0.3, 0.5 and 0.7 g.100 g-1 solution) and glycerol (25, 30 and 35 g.100g-1 CPI). The polymeric films were produced by the "casting" technique. The tensile strength values ranged from 7.2 to 10.7 MPa and the elongation values from 39.6 to 45.8%. The water vapor permeability (WVP) values ranged from 3.2 to 5.5 (g.mm.m-2.d-1.kPa-1) and the CPI had an average protein content of 97.87% protein (d. b.). It was concluded that the nanocomposite films produced from CPI with MMT were promising from the standpoint of their mechanical properties, visual appearance and easy handling, as well as for their low water vapor permeability and low water solubility. With respect to their mechanical properties, the concentrations of CPI and MMT were the main factors influencing the development of the nanocomposite films. The results obtained from the experimental design indicated that 3.5 g of CPI.100 g-1 solution, 0.5 g of MMT.100 g-1 solution and 30 g of glycerol.100 g-1 CPI would be the ideal parameters for the development of nanocomposite films by "casting".
Whitemouth croaker; Byproduct; Protein isolate; Composite films; Properties
