Performance of Plasma-Modified Peanut Hulls on the Physicochemical and Functional Properties of Waxy Starch Films

In this study, the effect of ethylene (E), styrene (S), and hexamethyldisiloxane (H) plasma-modified peanut hulls (PF) on the structural and functional properties of waxy starch-based films (WS) was investigated. TGA analysis confirmed the deposition of the coating on the PF surface after plasma treatment. Nevertheless, using the same operating conditions, the treatments resulted in partially (PFE and PFS) and fully (PFH) coated PF. During the gelatinization process, the fully coated PF interacted more strongly with starch molecules, displacing starch-glycerol interactions and improving the contact angle (from 85° to 93°), water vapor permeance (0.23-0.15 g/daym²Pa), and the storage modulus (from 192 to 554 MPa). Conversely, the partially coated PF were attracted to each other, limiting interaction with starch, resulting in films with high hydrophilicity and low rigidity. Thus, the plasma-modified PF type interacts to a different extent with starch molecules, which determines the functional properties and potential applications of the films in the packaging field.