Biopolymer-Based Films from Sodium Alginate and Citrus Pectin Reinforced with SiO(2)

Blend films based on sodium alginate (SA) and citrus pectin (P) reinforced with different concentrations of SiO(2) (0–10% w/w) were developed in this study. From the morphological (SEM) and structural (FT-IR) evaluation, it was verified that the incorporation of the reinforcing agent did not drastically modify the microstructure of the films, nor did new chemical bonds form. However, the XRD results suggested a slight reduction in the crystallinities of the blends by the incorporation of SiO(2). Among the formulations prepared, the addition of a 5% reinforcing agent was responsible for the simultaneous improvement of mechanical and barrier properties. Comparing the control sample (SA/P) with the SA/P/5.0%SiO(2) film, the tensile strength increased from 27.7 ± 3.7 to 40.6 ± 4.5 MPa, and the water-vapor transmission rate decreased from 319.8 ± 38.7 to 288.9 ± 23.5 g m(−2) day(−1). Therefore, SiO(2,) as a reinforcing agent in SA/P blends, represents a simple and effective strategy for improving the properties of biopolymer-based films in applications, such as packaging.