EMULSIFIED FILMS PRODUCED WITH PROTEINS EXTRACTED FROM WHITEMOUTH CROAKER BYPRODUCTS: DEVELOPMENT AND CHARACTERIZATION

This study aimed to develop and characterize biodegradable films from myofibrillar proteins from whitemouth croaker (Micropogonias furnieri) using stearic acid (SA) to improve its technological properties. The proteins extracted were lyophilized, characterized, and used to prepare the films. The filmogenic solutions were dried on a silicone stand at 35 degrees C for 14 h in an incubator oven according to the casting method. The region with the best mechanical, physical, and barrier properties in the films was defined by a full factorial design. The lyophilized myofibrillar proteins (LMP) had protein content of 96.03%. The analysis of the experimental design results indicated the best conditions to prepare the optimized film were 2.84% LMP, 3.18% SA, and 78.41% SDS (sodium dodecyl sulfate). The control films were prepared with 2.84% LMP and 30% plasticizer. The optimized film had significantly lower water vapor permeability (5.87E-11 g m m(-2) s(-1) Pa-1), higher tensile strength (6.35 MPa), and lower elongation (235.60%) compared with control (p <= 0.05). It also had lower transparency values and excellent UV barrier property, which indicates a tendency to opaque. Thermal stability was good and the microstructure revealed a structural change in the filmogenic matrix, confirmed by x-ray diffraction, which indicates influence of SDS and SA on film crystallinity. Solubility increased by 22% and swelling decreased slightly in the optimized film compared to the control. The results obtained represent a positive contribution with the use of fish byproducts by applying alternative, sustainable technologies.