Improvement of antimicrobial activity of sago starch/guar gum bi-phasic edible films by incorporating carvacrol and citral

Abstract Edible films and coatings formulated with antimicrobial agents and renewable biopolymers have attracted research interest because of their contribution towards food safety and biodegradability. In this study, a biphasic edible film based on sago starch (SS) and guar gum (GG) was developed, and thereafter, two essential oils (EOs), namely, carvacrol (0.75% w/w) and citral (1.0% w/w) were impregnated either individually or in combination into the blend. The morphology, optical, structural, and water barrier properties of the films were evaluated by various analytical techniques. Scanning electron micrographs exhibited the roughness on the top surface of the EO incorporated blend films, whereas the confocal microscopy confirmed the dispersibility of EOs into the blend. The tensile strength of films significantly reduced and elongation at break increased when EOs were incorporated. The SS/GG/EO films exhibited excellent antimicrobial activity against Bacillus cereus and Escherichia coli. These results indicate that EOs have the potential as antimicrobial agents in SS/GG films for use as active packaging materials in the food applications.