Valorization of cranberry bean processing residues into functional protein-isolate films with antioxidant properties

The growing demand for sustainable packaging has driven the valorization of agricultural byproducts within a circular economy framework. This study explored the extraction of protein isolate from cranberry bean ( Phaseolus vulgaris L.) processing residues and its use in developing bioactive edible films incorporated with clove essential oil (CEO, 0.1–0.5% w/w). The films were evaluated for mechanical, barrier, optical, structural, and antioxidant properties. CEO incorporation significantly reduced water vapor permeability by 24.9% (3.46 to 2.60 × 10 -10 g·m -1 ·s -1 ·Pa -1 ). Tensile strength decreased (55.18 to 38.18 MPa), while elongation at break increased by 50.5%, indicating improved flexibility. Film solubility (38.50 to 42.96%) remained within acceptable limits. FTIR analysis further confirmed interactions between CEO compounds and protein chains, indicating modifications in the film network structure. Additionally, antioxidant properties were markedly enhanced, with total phenolic content rising from 0.82 to 16.89 mg GAE/g, DPPH scavenging from 16.85 to 80.59%, ABTS from 23.04 to 98.40%, and reducing power from 0.59 to 12.89 mg AAE/g. These findings demonstrate that cranberry bean protein isolate is a promising biopolymer for producing flexible, antioxidant-active films suitable for sustainable packaging applications.