Valorization of cassava starch waste for multifunctional packaging: Optimizing antimicrobial, thermal, mechanical,...

Cassava starch is a major global starch source, with 80 % of its production generating waste, predominantly cassava bagasse. This study valorized cassava bagasse by developing active packaging films incorporated with nutmeg essential oil (NO) at varying concentrations (1-3% w/w). The integration of NO increased film thickness from 0.38 mm to 0.67 mm, and tensile strength (TS) from 0.66 MPa to 1.19 MPa, while reducing density (1.33-1.21 g cm^-3), transparency (75.51-53.62%), and solubility. Films exhibited higher opacity (46.72-58.73%) and enhanced color intensity. SEM images revealed fewer oil droplets and a more microporous structure, indicating improved compatibility. FT-IR confirmed that NO did not alter the film's chemical composition, although XRD indicated enhanced crystallinity. Thermal stability improved as the maximum decomposition temperature increased from 299.28 °C to 301.48 °C. Migration analysis demonstrated enhanced phytochemical release in different solvents, following Fickian-type diffusion. HS-SPME analysis revealed p-cymene, terpinen-4-ol, γ-terpinene, sabinene, and safrole as the dominant volatiles, contributing to antioxidant and antimicrobial activity. Disk diffusion assays showed N03 exhibited the largest inhibition zones against E. coli (20.67 mm) and S. aureus (31.33 mm). Moreover, grapes packed with N03 (NO 3%) film maintained quality for 10 d at room temperature, with reduced weight loss, color variation, and microbial proliferation compared to controls. The findings confirm that NO incorporation significantly enhanced the physicochemical, structural, and bioactive performance of cassava bagasse films, demonstrating strong potential for sustainable food packaging applications.