PH-responsive and Antimicrobial Starch-based Smart Packaging Films Containing Black Rice Anthocyanins and SBA-15@CMA

Abstract

Cinnamaldehyde (CMA)-loaded mesoporous silica (SBA-15@CMA) was successfully synthesized and combined with varying concentrations of black rice anthocyanins (BRAs) to fabricate pH-responsive, paper-based intelligent food packaging materials using acetylated potato starch as the polymer matrix. The influence of BRA on the physicochemical, mechanical, antioxidant, and antibacterial properties of the food packaging materials was systematically examined. The results demonstrated that the incorporation of an appropriate amount of BRA significantly improved the uniformity, flexibility, and overall functionality of the packaging films. At a BRA concentration of 0.04 g, the food packaging materials exhibited superior mechanical properties (tensile strength: 15.23 MPa), low oxygen transmission rate (91 g/m²·d), and minimal water vapor permeability (5.93 × 10⁻⁷ g·m⁻¹·h⁻¹·Pa⁻¹). The film containing 0.08 g BRA demonstrated the highest antioxidant activity, with an ABTS radical scavenging rate of 73.49%. In addition, the films exhibited antibacterial activity against E. coli and S. aureus, with inhibition zone diameters of 7.91 and 7.64 mm, respectively. Importantly, the films displayed clear and reversible color transitions in response to ammonia and acetic acid vapors, demonstrating their potential for real-time freshness monitoring in intelligent food packaging applications. These findings suggest that the pH-responsive SBA-15@CMA/potato starch/paper-based composites offer excellent potential as sustainable, active, and intelligent packaging materials.

Graphical Abstract