Sustainable Antioxidant Cassava Starch–Pectin Films Functionalized With Guava Peel Nanoparticles for Food Packaging

ABSTRACT In this study, nanocomposite films were developed from cassava starch and pectin, functionalized with guava peel polyphenol nanoparticles and reinforced with a polylactic acid bilayer. Guava peel, an agro‐waste, is a rich source of polyphenolic compounds. It was processed into nanoparticles and integrated into the biopolymer matrix to improve structural, functional and protective properties. Mechanical evaluation demonstrated that tensile strength increased from 9.05 MPa in the control film to 15.6 MPa in the film containing 25% peel nanoparticles (PCS/G5), indicating effective reinforcement of the polymer network. Barrier properties were enhanced, with water vapour permeability reduced to 0.05 × 10 −10 g m −1 s −1 Pa −1 in the PCS/G5 film. The bioactivity of the films was markedly improved, with antioxidant capacity reaching 69.8% DPPH radical scavenging compared with 5.9% in the control, and antimicrobial activity resulting in inhibition zones of 18.5 mm against Escherichia coli and 24.5 mm against Staphylococcus aureus . Soil burial assays confirmed complete biodegradation within 42 days. Packaging trials using spray‐dried stevia powder validated the films' performance, showing retention of 70.1% antioxidant activity after 5 months of storage compared with 52.9% in kraft paper packaging, while maintaining powder flowability and bulk density similar to commercial laminate films. The findings demonstrate that guava peel–fortified cassava starch–pectin composites combine mechanical strength, barrier protection, bioactivity and biodegradability, establishing their potential as high‐performance materials for sustainable food packaging.