Green Synthesis of Silver Particles Using Pecan Nutshell Extract: Development and Antioxidant Characterization of Zein/Pectin Active Films

(1) Background: The replacement of petroleum-based plastics with sustainable biopolymer films is crucial for global food preservation. Biopolymers like zein and pectin offer biodegradable and compostable alternatives but often require functionalization. This study develops and characterizes a novel antioxidant film by incorporating silver microparticles (AgMp) derived from the valorization of an agricultural waste product: pecan nutshell extract. (2) Methods: AgMp were synthesized via green reduction method using the extract. These bioactive microparticles were subsequently incorporated into a zein/pectin polymeric solution using the solvent-casting technique. The particles and the active films were characterized using FTIR, SEM, and antioxidant assays (ABTS, DPPH, and FRAP). (3) Results: The extract and AgMp exhibited a potent antioxidant activity (100% inhibition for ABTS/DPPH). SEM analysis confirmed the scale of 0.545–1.033 µm, classifying the material as microparticles. The final films retained a dose-dependent antioxidant activity (66.78% for ABTS and 53.67% for DPPH). (4) Conclusions: This work validates that pecan nutshell extract as an effective green reducing and capping agent. The resulting film possesses significant antioxidant activity, offering a promising alternative for active food packaging applications, such as bioactive pads or inserts.