Biodegradable active composite film based on pea protein isolate, sage seed gum, and cumin essential oil: Fabrication and characterization

The present study perused the physicochemical, mechanical, thermal, barrier, and optical properties of pea protein isolate (PPI)-Sage seed gum (SG) (3:1, 1:1, and 1:3) composite films incorporated with cuminum essential oil (CEO, 0, 1, and 2 %). Results indicated that the thickness, contact angle (CA), yellowness index (a*), total color differences (∆E), and opacity (OP) significantly enhanced with increasing PPI portion and CEO concentration (p < 0.05), as well as heterogeneous and inconsistent structure were increased in film surface due to protein agglomeration and oil droplets. However, the moisture content (MC), water solubility (WS), and swelling ratio (SR) decreased. Results also indicated that the antioxidant property significantly increased (P < 0.05) following the increase in CEO concentration. The highest tensile strength (TS) and elastic modulus (EM) and the least elongation at break (EAB) in PPI 3-SG 1–0 % were estimated. The potential antimicrobial property of CEO containing film was confirmed, and the maximum inhibition zone for E.coli, S.aureus, C.albicans, and A.niger were measured in film containing 2 % CEO. The barrier properties of the film against water and oxygen (WVP, OXP) diminished with increases the SG ratios, due to the hydrophilic nature of SG. The FTIR analysis identified the functional groups in film components and the interaction between film components. The DSC thermogram indicated the thermal stability of films and the highest decomposition temperature in PPI 3-SG 1–2 % film. XRD revealed a semi-crystalline structure of biopolymer active films. With the increase of SG portion and CEO concentration, the crystallinity of the films was enhanced. Results also indicated that prepared films were more than 90 % biodegradable.