Enhanced barrier and antioxidant properties of gelatin films by structural-colored bioactive materials for food packaging

Neoteric functional gelatin films were fabricated based on structural-colored bioactive materials and applied in practical food applications. The bioactive materials could induce the excellent shear-thinning structure and benefit the spreading, leveling and thus the film forming process. From FTIR, XRD, zeta potential, SEM and AFM, the hydrogen bonding and electrostatic interaction between bioactive materials (monascus red, phycocyanin, and safflower yellow) and biopolymers, could cause the compact network structure and improve the performance of final films compared to the films without bioactive materials, including chromatic appearance, mechanical characteristics (increasing tensile strength by 625.27%, 184.10% and 296.00%, respectively), barrier properties (decreasing oxygen transmittance rates by 96.27%, 85.81% and 94.58%; and increasing light opacity by 216.56%, 54.91% and 174.04%, respectively), and antioxidant activity (increasing ABTS free radical scavenging property by 92.24%, 110.12% and 111.70%, respectively). During blueberry preservation, the functional films could effectively delay the weight loss and hardness reduction. When packaging food ingredients, functional films could be cooked together with rice and oats for obtaining excellent-looking porridge with special masticatory sensation, and have little effect on the odors (electronic-nose). Therefore, gelatin films incorporated with bioactive materials could potentially act as fresh-keeping packaging or direct eating/cooking packaging, and exhibit environmental-protective merits and recyclability, holding promises as an alternative for plastic packaging.