Abstract
This work was dedicated to improving the utilization rate of yellow peach peel (YPP), with the addition of sodium alginate (SA) and glycerol (G) to prepare a biodegradable antioxidant film. First, the formulation of the film was optimized via response surface methodology (RSM) combined with the multi-index comprehensive evaluation method, considering physical properties including tensile strength (TS), elongation at break (E%), water solution (WS) and light transmittance (T). The RSM results displayed the best process condition was 2.50% of YPP, 0.60% SA and 0.80% of G (based on water) and compared with pure YPP film and YPP-SA film, the optimized (YPP-SA-G) film presented excellent properties with TS of 21.52 MPa, E of 24.8%, T of 21.56% on 600 nm, and WS of 41.61%, the comprehensive evaluation score of the film was 0.700. Furthermore, the films were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). FTIR analysis showed the main interaction of hydrogen between YPP, SA and G make the film has excellent compatibility, and the SEM images displayed that the film was dense and compacted with a little roughness. In addition, the optimized film had excellent thermal stability, suggested by TGA and XRD showed that the film's crystal structure has been changed significantly when the SA and G were mixed in. The TPC and the ability of DPPH radical scavenging of the YPP-SA-G film was 17.68 mg·g-1 of GAE and 18.65%, then potential packaging applications were evaluated using soybean oil and the YPP-SA-G antioxidant film significantly decreased peroxide value (POV) to delay oil oxidation during storage. Therefore, the YPP-SA-G film is expected to provide a new theoretical basis for the use of food processing by-products and the packaging industry.