Characterization of antibacterial polyvinyl alcohol/sodium alginate films loaded with stigmasterol isolated from corn silk ( stigma maydis) for food packaging

This study aimed to develop novel polyvinyl alcohol/sodium alginate (PVA/SA) films containing stigmasterol (STG), isolated from corn silk. STG at different concentrations (0, 0.3, 0.6, 0.9, and 1.2 % w /w) was mixed into the film-forming blend. The physical properties, color traits, surface shapes, mechanical properties, thermal characteristics, and crystallinity of the prepared films were evaluated. Gradually adding STG up to 1.2 % in the film blend increased the opacity from 0.8 to 4.6 A/mm. It decreased the solubility, swelling, water vapor permeability (WVP), and moisture of PVA/SA films from 59 to 34.7 %, 49 to 41.5 %, (4.8 to 3.8x 10- 10 g m- 1 s- 1 Pa- 1 ), and 13.4 to 10.7 %, respectively. In addition, the surface micrographs demonstrated a smoother surface when minor STG concentrations were used, whereas elevated concentrations caused rough and irregular surface characteristics. FT-IR analysis revealed a physical interaction between the STG and the PVA/SA matrix. The PVA/SA films with STG exhibited adequate thermal stability. The addition of STG to the PVA/SA-prepared films exhibited good antioxidant and antimicrobial properties. Moreover, the developed films significantly decreased the changes in the browning index during cold storage and increased the overall acceptability of white button mushrooms.