Preparation and characterization of nanosilica‐incorporated starch/k‐carrageenan active food packaging film functionalized by <i>eucalyptus</i> oil

Abstract The growing environmental concerns regarding usage of conventional petroleum‐based plastics have prompted the investigation of sustainable and biodegradable alternatives for food packaging applications. The present research focuses on the development and characterization of flexible food packaging films based on starch and k‐carrageenan, plasticized with mixed bio‐plasticizers like glycerol, castor oil, mannitol, sorbitol and xylitol. Starch, a natural polymer obtained from renewable resources, offers a promising base for the development of biodegradable films. However, native starch films tend to be highly brittle and moisture‐sensitive, which limits their direct practical applications. To overcome these limitations, plasticizers are added to enhance the flexibility and overall performance of the films. The nanosilica isolated from industrial waste was included to reinforce the plasticized films and to improve the mechanical strength and barrier properties. To give additional antimicrobial functionality, eucalyptus essential oil was incorporated. The addition of mixed bio‐plasticizers enhanced the flexibility almost eightfold. Fourier transform infrared spectroscopy analysis of films provided detailed insights into the chemical interactions and structural integrity of the modified starch films, ensuring that the plasticizers and essential oil were effectively integrated. The water contact angle of the modified film was 84° as compared to 38° for pristine starch films. The water vapor transmission rate analysis showed an improvement (about fivefold) in barrier property of the developed films. The results demonstrated that the starch/k‐carrageenan film modified with selected plasticizers, nanosilica and essential oil exhibited significantly improved mechanical properties, flexibility, moisture resistance and antimicrobial efficacy. © 2025 Society of Chemical Industry.