Development and characterization of cinnamon essential oil incorporated active, printable and heat sealable cellulose nanofiber reinforced hydroxypropyl methylcellulose films

Cellulose nanofiber (CNF) reinforced hydroxypropyl methylcellulose (HPMC) films were incorporated with antioxidant cinnamon essential oil (CEO) to develop active, printable, and heat-sealable films. CEO was carried into the films via three types of active systems: β-cyclodextrin (β-CD) encapsulation, cellulose nanocrystal (CNC) Pickering emulsion (CNC-P), or the combination thereof (CNC-P/β-CD). The films were characterized for their mechanical, physicochemical, structural, thermal, and optical properties along with CEO release, printability, and heat seal strength. The Control film (without active CEO) and CNC-P film showed the highest transparency, 17.02% and 18.17%/mm, respectively, followed by the CNC-P/β-CD (12.86%/mm) and β-CD (11.68%/mm) films. A significant difference (P < 0.05) in water vapor permeability (WVP) was observed between the Control film stored at 33% RH (72.01 g mm/m2 d kPa) and 53% RH (54.45 g mm/m2 d kPa) whereas no difference in WVP for β-CD, CNC-P, and CNC-P/β-CD films under RH range of 33–84% (P > 0.05). The presence of active CEO in the films enhanced the moisture barrier and stability of films without influencing the mechanical and thermal properties of the films. The CEO incorporated films via both CNC Pickering emulsion and β-CD encapsulation prolonged the release of CEO. All CEO incorporated films were printable by inkjet and stamp inks and showed good heat seal strength (∼61–73 N/m). This study provided new strategies to develop cellulose-based active films with extended antioxidant function and sealable and printable properties to replace single-use plastic packaging for various food, especially high-fat food items.