Fabrication and characterisation of sustainable biofilm derived from starch and waste African tulip flower extract for food packaging applications

Petroleum-based plastics possess persistent environmental and human health risks due to their non-biodegradability and accumulation in ecosystems. The present study develops biodegradable starch-based biofilms incorporating waste African tulip flower extract (ATFE). Three formulation matrices (AT1, AT2, AT3) and a standard (S) were prepared using the solvent casting method with a constant dose of starch and Maida (5 g), and varying proportions of AFTE, citric acid, vinegar, and formaldehyde. The prepared biofilms were characterised according to their physical, chemical, and mechanical properties. The results revealed that AT1 exhibited the lowest moisture content (7.08 %) and high transparency, whereas AT2 showed the highest tensile strength (11.667 MPa) and moderate hydrophobicity (39°). Furthermore, AT3 displayed the highest WCA (49°) but a lower TS (6.03 MPa) due to an excess extract content. The results suggest that the ATFE polyphenols, combined with citric/formaldehyde crosslinking, reinforce the polymer matrix, enhancing film strength and restricting moisture uptake in AT1/AT2. In contrast, the excess hydrophilic content in AT3 increases water affinity. Finally, in 30-day biodegradation tests, the mass loss in soil/sand reached 40–66 % (highest in S), while AT1/AT2 showed a loss of 27–60 %. AT1/AT2 lost up to 15–28 % of their mass, whereas in S, it was 5–11 % in aqueous and photodegradation conditions. The addition of ATFE enhanced mechanical and barrier properties, offering a promising alternative to petroleum plastics.