From Food Waste to Edible Packaging: Development and Characterization of Biodegradable Gelatin Films with Microfibrillated Cellulose from Cowpea Pod Skin (Vigna unguiculata) and Corn Straw (Zea mays)

This research focused on the development and characterization of gelatin-based films incorporated with cellulose microfibrils (CMFs) extracted from cowpea pod skin (<i>Vigna unguiculata</i>, CPMC) and corn straw (<i>Zea mays</i>, CSMC). The use of CPMC to produce gelatin films has not been previously reported in the literature. Eleven formulations were prepared based on a 2² factorial design with four axial and three central points, in addition to a control film (FC) composed of 1.00% gelatin and 1.00% glycerol without CMFs. The physical, chemical, structural, and mechanical properties of the films were evaluated. The optimized formulation (FO), containing 1.00% CPMC and 1.00% CSMC, exhibited a four-fold increase in tensile strength (2.71 MPa) compared to the control. Water vapor permeability was significantly reduced (from 6.33 × 10^-4 to 2.82 × 10^-4 gH₂O·mm/m²·h·mmHg), and solubility decreased to 75.82%. Biodegradability was modulated, with FO exhibiting 73.06% degradation over three days versus complete degradation of FC within one day. The incorporation of CMFs, particularly from agro-industrial residues, significantly improved the structural integrity and barrier properties of the films, highlighting their potential for use in biodegradable packaging systems.