AbstractBACKGROUNDThe microstructure and the physical, mechanical, barrier and thermal properties of films based on different concentrations of protein isolated from croaker waste (CPI) and palm oil (PO) were analyzed. Films were elaborated by a casting technique using 2, 3 and 4 g CPI 100 g−1 of a filmogenic solution and 0, 10 and 20 g of PO 100 g−1 CPI.RESULTMicrostructure of the film surfaces of CPI with PO showed no presence of lipid droplets dispersed in the filmogenic matrix, although a rough surface was present. Films with 3% and 4% CPI and 20% PO had the lowest rates of water vapor permeability. When there was an addition of PO to the reduced tensile strength of the films, regardless of the concentration of CPI, this addition reduced the elongation of films with 3% and 4% CPI; however, it did not influence films with 2% CPI, which did not differ from the control film (0% OP). Thermal analysis revealed that films with the highest PO percentage had a lower initial weight loss when compared with other films, due to higher hydrophobicity.CONCLUSIONThe use of protein isolate obtained from fish residues of low commercial value and palm oil is viable for the production of biodegradable films because the latter constitute good barrier properties and thermal stability. © 2015 Society of Chemical Industry