Optimization of Antibacterial Edible Carboxymethyl Cellulose-L-Arginine Coating Formulations Incorporating Rosemary Oil Extract Using Response Surface Methodology

Justification: The growing demand for eco-friendly and safe food preservation methods has driven interest in edible antimicrobial coatings. This study integrates carboxymethyl cellulose (CMC) as a biodegradable matrix with L-arginine and rosemary oil extract, known for their antimicrobial and antioxidative properties. This formulation reduces reliance on synthetic preservatives and plastic packaging, aligning with sustainability and food safety goals.

Objective: To optimize the formulation of edible antimicrobial coatings by evaluating the effects of rosemary oil concentration, Tween 80 levels, and ultrasonication time on antimicrobial activity and emulsion stability.

Methods: Coating solutions were prepared by dissolving 0.5% (w/w) CMC in deionized water, followed by the addition of 0.25% (w/w) L-arginine and varying concentrations of rosemary oil (1.5–4.5 mL) and Tween 80 (1–5% v/v). The emulsions were homogenized using ultrasonication (5–25 min, 70% amplitude). Antimicrobial efficacy was evaluated against Escherichia coli and Listeria innocua using inhibition zone assays, and emulsion stability was determined gravimetrically. A Box-Behnken design was employed to optimize responses.

Results: ANOVA indicated significant quadratic effects of rosemary oil, Tween 80, and ultrasonication time on inhibition zones and emulsion stability (p < 0.001). Optimal conditions were identified as 4.4 mL rosemary oil, 1.6% Tween 80, and 5 minutes ultrasonication, yielding inhibition zones of 10.38±1.29 mm (E. coli) and 11.24±0.03 mm (L. innocua), with 84.16±1.89% emulsion stability.

Significance: The optimized coating formulation demonstrates strong antimicrobial activity and stability, offering a sustainable alternative for emulsion coating-based food preservation.