Novel applications of black pepper essential oil as an antioxidant agent in sodium caseinate and chitosan based active edible films

In the current study, sodium caseinate and chitosan-based composite edible films were developed with the incorporation of black pepper (Piper nigrum) essential oil (BPO) in various concentrations (0.05, 0.1 and 0.15 %) for potential food packaging applications. The chemical composition of BPO was determined using GCMS and the major compound detected were beta-caryophyllene, limonene, beta-phellandren, pinene, copaene and alpha-humulene. The addition of BPO resulted in an increase in the thickness, EAB, WVP, moisture content and swelling index values of the films; however, the TS and water solubility decreased. The inclusion of BPO led to a substantial enhancement in the DPPH and ABTS radical scavenging capabilities of the edible films. SEM micrographs demonstrated intermolecular interaction between BPO, sodium caseinate, and chitosan. FTIR spectra confirmed the interaction of the functional groups of the polymers and BPO. The incorporation of the BPO increased the crystallinity of the films. Moreover, the thermal analysis including TGA, DSC and DTG demonstrated an increase in the thermal stability of the edible films with the addition of the BPO. These findings demonstrated that sodium caseinate and chitosan composite based edible films loaded with BPO can be used as sustainable active food packaging material.