Sustainable active bio-composite films based on cassava starch reinforced with durian rind nano cellulose and cinnamon essential oil: Optimization and characterization

Abstract

The development of sustainable active bio-composite films based on cassava starch (CS), reinforced with durian rind cellulose nanofibre (CNF) and functionalised with cinnamon essential oil (CEO), was investigated to valorise agricultural waste. The CNF reinforcement was isolated from durian rind using a TEMPO-mediated oxidation method combined with ultrasonication and subsequently incorporated into the starch matrix along with CEO. Response surface methodology (RSM) with a central composite design (CCD) was employed to model and optimise the effects of CNF and CEO concentrations on mechanical properties, water barrier performance, as well as antibacterial activity. The optimisation process identified an optimal formulation containing 5% CNF and 2% CEO. This formulation yielded a maximum tensile strength of 10.45 MPa and a Young's modulus of 188.2 MPa. Furthermore, the simultaneous presence of CNF and CEO effectively enhanced hydrophobicity, reducing the water absorption capacity to 37.5%. The antibacterial modelling revealed broad-spectrum activity, with a more pronounced effect against Gram-positive bacteria. The films exhibited significant inhibition zones against Staphylococcus aureus (up to 2.5 cm) and Escherichia coli (up to 1.0 cm), as demonstrated by the response surface plots. These findings confirm that the durian rind-derived CNF combined with CEO is a potent reinforcement for sustainable starch-based active food packaging with tunable mechanical and antimicrobial properties