pH‐Sensitive and Antimicrobial ZnO‐Ath Nanomaterials for Innovative Food Packaging Solutions

Abstract Growing concerns about food preservation and safety have driven the development of smart packaging capable of providing real‐time information about product freshness. Among the most promising strategies are pH‐sensitive materials based on natural compounds that change color in response to spoilage. This study aimed to develop innovative pH‐sensitive materials for packaging applications by combining zinc oxide (ZnO) nanoparticles with anthocyanins (Ath). Three ZnO–Ath composites with different ratios were synthesized and characterized. Color change tests confirmed that these nanocomposites exhibited clear pH‐dependent color variations, making them strong candidates as visual freshness indicators. Fourier transform infrared spectroscopy (FTIR) evidenced coordination interactions between Zn 2 ⁺ and anthocyanins. Density functional theory (DFT) calculations explored the structure and reactivity of the ZnO–Ath complexes. X‐ray Diffraction (XRD) showed a reduction in ZnO crystallite size due to anthocyanin stabilization. Scanning electron microscopy (SEM) revealed uniform nanoparticle dispersion, and Thermogravimetric Analysis (TGA) confirmed improved thermal stability. Furthermore, the nanocomposites displayed excellent antioxidant and antibacterial properties, enhancing their potential as protective agents against food spoilage. The nanocomplex retained its pH sensitivity even after incorporation into a poly(vinyl alcohol) matrix, as demonstrated by distinct color changes under varying pH conditions, reinforcing its suitability for smart packaging applications.