Preparation and Characterization of Yellow Peach Peel/Sodium Alginate/Glycerol Antioxidant Film Applicable for Oil Package

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.