3D printed corn starch–gelatin film with glycerol and hawthorn berry ( Crataegus pinnatifida ) extract

The effects of glycerol (1, 2, 3, 4, and 5% wt/vol) and hawthorn berry (Crataegus pinnatifida) extract (HBE) (2, 4, 6, 8, and 10% wt/vol) on texture of film-forming blends, film's physical, mechanical, and antimicrobial properties of 3D-printed corn starch–gelatin edible films (CSG) were assessed. The mechanical properties of the hydrogel, the thickness of the film, and its water solubility improved as the glycerol concentration increased. In addition, the formulation with the desirable properties was observed in 4% (wt/vol) glycerol's film, with the elongation at break (%E) at 71.57%. Meanwhile, higher HBE improved film's thickness, water solubility, yellowness, redness, and color index (∆E). A film with 6% (wt/vol) HBE exhibited good tensile strength (TS), and %E hence was determined as the final film-formulation in 3D-printed CSG films. Films with 4% (wt/vol) glycerol and 6% (wt/vol) HBE inhibited against Pseudomonas aeruginosa, suggesting it can be utilized in antibacterial food packaging. Practical applications Because of their high antioxidant content, hawthorn berries have long been used as a functional food and folk medicine. Furthermore, due to their antibacterial properties, they could be incorporated into edible film to create active packaging. The corn starch–gelatin (CSG) edible film incorporated with hawthorn berries extract was developed by using the 3D printing method. The effect of the 3D printed CSG edible film with various concentrations of glycerol and hawthorn berry extracts on the CSG film forming blend, physical and mechanical properties of the film were assessed. Furthermore, the antibacterial properties of hawthorn berries extract as well as a 3D printed CSG edible film enhanced with hawthorn berries extract were evaluated. The outcome of this work was expected to be beneficial to food industry, in particular packaging, to comprehend the effect of edible film and its properties when printed in 3D.