STARCH FILMS INCORPORATED WITH CHITOSAN/CARBOXYMETHYLCELLULOSE POLYELECTROLYTE COMPLEXES AND VITAMIN B3

Starch is a promising biopolymer for packaging films due to its low cost and wide availability; however, its application remains limited compared to the physical properties of conventional plastics. A promising strategy to optimize the properties of starch films involves the incorporation of polyelectrolyte complexes (PECs). PECs can enhance the mechanical strength of the films and additionally serve as efficient carriers for the controlled release of bioactive compounds, such as vitamin B3, thereby expanding the functionality of the packaging material. In this context, starch-based films incorporating polyelectrolyte complexes (PECs) of chitosan and carboxymethylcellulose, with or without the addition of vitamin B3, were developed. Films were prepared using the casting method. Four formulations, optimized based on previous unpublished studies, were tested: (a) starch film (ST); (b) starch film with vitamin B3 (ST-B3); (c) starch film with PEC (ST-PEC); and (d) starch film with PEC and vitamin B3 (ST-PEC-B3). The films were characterized in terms of physical properties (thickness, solubility), mechanical properties (tensile strength), and structural features (Scanning Electron Microscopy - SEM, X-Ray Diffraction - XRD, FTIR, and profilometry). The results demonstrated that PECs and vitamin B3 significantly influenced the film properties. Specifically, the addition of vitamin B3 (ST-B3) increased the opacity of the films, possibly due to the dispersion of the vitamin within the matrix, and led to an increase in moisture content (27.57% ± 3.58) and solubility (51.98% ± 1.57), which may be attributed to the hydrophilic nature of vitamin B3. In contrast, SEM analysis suggested that the addition of PECs (ST-PEC) resulted in a thicker and more uniform structure, indicating a structural reinforcement effect provided by the PECs. This result was confirmed by mechanical analysis, in which the ST-PEC films exhibited higher tensile strength (939 MPa). Ongoing studies aim to explore the application of these films as coatings, investigating whether the incorporation of PECs and vitamin B3 contributes to structural reinforcement and, consequently, to the extended shelf life of perishable foods.