Preparation and characterization of chitosan-based bioactive films incorporating Moringa oleifera leaves extract

The addition of bioactive components, especially antioxidants, and plasticizers are good strategies to improve the properties of edible films. This study aimed to evaluate the effect of adding Moringa oleifera ethanolic extract (MEE) and glycerol (G) in chitosan (C) films. Two concentrations of MEE (0.07 and 0.15% wt) and two concentrations of G (20 and 40% wt) were incorporated and their effect on the physical, mechanical, optical, barrier, structural, morphological, and bioactive properties of the film was evaluated. In physical properties, the incorporation of G increased the density and moisture in 78.2% and 71.3%, respectively. However, the addition of MEE affected the solubility. Films with 40% wt of G and MEE exhibited an antiplasticizing effect, which was observed in a decrease of 38.3% in tensile strength (TS) and 72.1% in percentage of elongation at break (% E b ) values. In the optical properties, the addition of MEE acted as a barrier to light transmission. The water vapor transmission rate (WVTR) of some films showed a decreased up to 6.5% due to the presence of MEE compared to control films. In structural properties, infrared spectroscopy revealed that the structure of the films was slightly modified. Scanning electron micrographs showed that the films were homogeneous and films with 40% wt G showed two phases on their surface. Films with 40% wt G and 0.15% wt MEE presented the highest content of phenolic compounds and antioxidant activity. This formulation showed suitable physicochemical properties and could be considered as a potential material for active packaging for food products. Graphic abstract