Boosting the loading dosage of cinnamon essential oil within edible packaging film via the multiple cross-linking strategy for effective shrimp preservation

Cinnamon essential oil (CEO) has been extensively employed as active compound in the active packaging film for food preservation, whereas its volatilization during the fabrication process restricted the loading and preservation effect. Herein, the multiple cross-linking strategy was proposed to design and construct the novel sodium carboxymethyl cellulose (CMC)/cellulose nanofiber-cinnamon essential oil (CNF-CEO)/citric acid (CA) (CCEA) film. Experimental characterization revealed that the multiple intermolecular crosslinks (e.g. hydrogen bond and ester bond etc.) within the polymer network reinforced the network and enabled the film to reduce the thermal movement of the molecular chains, which in turn prevented the CEO volatilization during processing. The optimized CCE_0.2A_0.2 with the mass ratio of 2:0.5:0.2:0.2 (g/g/g/g) possessed the highest CEO retention of 65.7%, which was much higher than the CCE_0.2A₀ of 11.71%. The oxygen, moisture barrier and tensile strength were improved from 8.94 cm³ μm/(m²·day·KPa), 1412.34 g m⁻²·24 h⁻¹ and 10.55 MPa for CCE_0.2A₀ film to 2.01 cm³ μm/(m²·day·KPa), 1296.93 g m⁻²·24 h⁻¹ and 25.93 MPa for CCE_0.2A_0.2, respectively. CCE_0.2A_0.2 also presented well antimicrobial activity and antioxidation capacity (67.25%). When employed as packaging film, the CCE_0.2A_0.2 film can effectively prolong the freshness of shrimp in refrigeration for 7 days. Our findings provided a novel perspective to suppress the volatilization of CEO during fabrication for effective food preservation.