Konjac glucomannan/zein active film loaded with tea polyphenol-ferric nanoparticles for strawberry preservation

With increasing global environmental awareness and concerns about food safety, biodegradable active packaging has garnered widespread attention. In this study, the stability and bioactivity of tea polyphenol (TP) were enhanced through the preparation of TP-ferric nanoparticles (TP-Fe NPs) using metal-polyphenol ion coordination. Moreover, the introduction of Fe ions can further enhance the antibacterial effects of TP-Fe NPs. Using the hydrogen bonding between konjac glucomannan (KGM) and zein to enhance the hydrophobicity and mechanical properties of the film. By employing KGM and zein as the matrix, we incorporated TP-Fe NPs as active fillers to create multifunctional active packaging films. This study aimed to meet the needs of food safety and sustainable development goals. The resulting film exhibited excellent water resistance (water contact angle: 117.73°), mechanical strength (tensile strength: 21.82 MPa, elongation at break: 94.30 %), ultraviolet-shielding ability (>99 %), biodegradability (5 days in soil), and antioxidant (>85 %) and antibacterial (>99 %) properties. Moreover, the film significantly reduced strawberry decay and extended its shelf life by 10 days. These findings provide new insights into the application of nanomaterials in active packaging, highlighting their potential and advantages in food preservation.