Enhanced functional pectin films incorporated with olive fruit extracts prepared by deep eutectic solvents

The effect of olive extracts extracted with deep eutectic solvent (DES: choline chloride/glycerol, dl-malic acid/ sucrose/glycerol, and citric acid/glycerol, respectively) on the structure, physical properties, and functional activities of pectin films, using DES both as a plasticizer and an extraction medium were explored. The findings revealed the integration of DES as a plasticizer was observed to increase film's water vapor permeability and elongation at break, while concurrently diminishing its opacity. Furthermore, the incorporation of DES-olive extracts significantly enhanced the tensile strength, moisture barrier property, and opacity of the film, as well as improved its antioxidant and antibacterial activities. The structural analysis indicated the interaction among DES, olive extracts, and pectin facilitated the development of more ordered structures within the films, thereby improving the thermal stability of the pectin-based films. In conclusion, pectin active films using DES as a solvent and plasticizer have the potential to be used to improve antimicrobial and antioxidant packaging materials along with acceptable water resistance.