Rapid-response nanofiber films against ammonia based on black wolfberry anthocyanins, polyvinyl alcohol and sodium alginate for intelligent packaging.

To develop novel intelligent indicator films, the mixture of anthocyanin (BWA), polyvinyl alcohol (PVA) and sodium alginate (SA) were spun into PVA/SA/BWA nanofiber films with BWA concentration of 0 %, 5 %, 10 %, and 15 % (based on PVA and SA) via electrospinning technology. The results showed that the BWA was sensitive to pH and was controlled release from films. With increasing BWA concentration, the fiber diameter, tensile strength, and elongation at break gradually decreased, while water contact angle, thickness, moisture content, and antioxidant properties gradually increased. The electrospinning films exhibited high sensitivity to ammonia with rapid color changes in 1 s and excellent color reversibility and color stability within 21 d. The application for shrimp packaging showed that the colorimetric response of the films was closely related to the changes in pH, total volatile basic nitrogen (TVB-N), and total viable count (TVC) of shrimp. This suggests that the prepared films are promising in application for intelligent packaging.