Development and characterization of a novel multifunctional film based on wheat filter flour incorporated with carvacrol: Antibacterial, antifungal, and insecticidal potentials

Wheat filter flour is a by-product derived from the modern wheat milling process. In this study, the influence of plasticizer type (glycerol (G) and sorbitol (S)) and content (25, 35, and 45 g/100 g polymer) on the wheat filter flour-based film was evaluated. Regardless of plasticizer type, increasing the plasticizer content enhanced moisture content, water solubility, and water vapor permeability of film samples. The S-plasticized films presented the greatest tensile strength and the lowest EAB%. The scanning electron microscope observations confirmed the uniform structure of G-plasticized film. Moreover, antimicrobial and physico-mechanical properties of G-plasticized (25%) film were evaluated at the presence of carvacrol (5 and 10 g/100 g polymer). The considerable improvement was achieved in water affinity (14.2%) and flexibility (8.6%) by incorporating 10% carvacrol in G-plasticized films. The greatest inhibitory properties of active wheat filter flour films were observed against Aspergillus niger. By increasing the carvacrol concentration in film-forming solution, the inhibitory activity against Listeria monocytogenes and Escherichia coli in the liquid food model system was increased by 90.3% and 66.95%, respectively. Moreover, the active wheat filter flour-based film released a considerable insecticidal activity against Sitophilus granarius and Tribolium confusum. This work offers a novel utilization of wheat filter flour as an inexpensive blend polymer to manufacture multifunctional active film, which provides a promising approach for pest management besides enhancing the safety of products.