Incorporation of anthocyanin into zein nanofibrous films by electrospinning: Structural characterization, functional properties, and ammonia color-responsiveness.

Green electrospinning for the production of freshness-indicating labels, employing entirely natural biopolymers and pigments, holds significance in the development of intelligent food packaging. This study aimed to prepare zein (Z) fibrous film (FF) incorporated with varying concentrations of anthocyanin (A; 0-0.5 %) through green electrospinning. Furthermore, we evaluated their structural characteristics, functional properties, and color responsiveness to ammonia. With an increase in A concentration from 0 % to 0.5 %, the average thickness and fiber diameter of the electrospun Z-FF increased from 68.6 μm to 102.0 μm and from 582.1 nm to 690.7 nm, respectively. At A concentration of 0.2 %, the A content and loading efficiency of electrospun ZA-FF exhibited the most optimal values (6.8 mg/g and 39.4 %). Surface hydrophobicity, thermodynamic properties, and mechanical characteristics of ZA-FF were significantly improved, attributable to changes in their secondary and crystal structures from the interaction of Z and A. In the ammonia color-responsiveness test, an obvious color change with Δ values of 13.1 and 20.0 was observed for -FF incorporated with A at concentrations of 0.2 % and 0.5 %, respectively. This study provides novel insights into the development of Z-based freshness-indicating labels via green electrospinning for intelligent food packaging, especially in livestock and marine products.