Physical Properties, Antioxidant Activity, and Antimi-crobial Properties of Edible Film Prepared from Black Plum Peel Extract as a Valuable By-product of Plum Processing

Abstract

Black plum peel (BPP) as a by-product of plum processing, has nutritional, antimicrobial, and antioxidant properties. In this study, the effect of black plum peel extract (BPPE) (0, 0.5, 1.5, and 2%) on physical (thickness, water solubility (WS), and water vapor permeability (WVP)), mechanical (tensile strength (TS) and elongation at break (EAB)), structural (FTIR; Fourier transform infrared spectroscopy) properties, antioxidant activity, and antimicrobial characteristics of chitosan/gelatin edible film was investigated. Antioxidant activity and total phenolic compound of BPP were 87.63% and 104.03 mg GA/g, respectively. Increasing the concentration of BPPE increased the WS, WVP, and antioxidant activity of chitosan/gelatin edible film, however reduced EAB and TS (p < 0.05). The results of FTIR presented the intramolecular and intermolecular interaction between chitosan, gelatin, and BPPE. By increasing the black plum peel extract, antimicrobial activity of films significantly improved which could be because of antioxidant and phenolic compounds of BPP. According to the results of this study, BPPE can be used to improve the quality of chitosan/gelatin edible film.