Preparation and characterization of nanosilica-incorporated starch/k-carrageenan active food packaging film functionalized by eucalyptus oil

The growing environmental concerns regarding usage of conventional petroleum-based plastics have prompted the investiga-
tion 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 flex-
ibility 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 dem-
onstrated that the starch/k-carrageenan film modified with selected plasticizers, nanosilica and essential oil exhibited signifi-
cantly improved mechanical properties, flexibility, moisture resistance and antimicrobial efficacy.
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