Development and characterization of alginate-based edible film incorporated with hawthorn berry (Crataegus pinnatifida) extract

In this study, alginate (AG) based edible films incorporated with Chinese hawthorn (Crataegus pinnatifida) berry extract (HBE) at the concentrations of 0, 1, 2, 3 and 4% (v/v) were developed and their physical, mechanical and antimicrobial properties were investigated. The results showed that the addition of HBE from 0 to 4% (v/v) enhanced the film thickness and water solubility, while reducing the moisture content of the films. The film containing 4% (v/v) HBE exhibited the highest water solubility (77.60%) and the lowest moisture content (14.54%). The colour profile analysis revealed that the presence of HBE increased the opacity, yellow and red intensity of the films. The incorporation of HBE produced films with reduced tensile strength (TS) and enhanced elongation at break (EB%). However, at 4% (v/v) HBE, the EB% of film decreased (from 43.57% to 27.67%) due to the high content of HBE. The inhibition zones against Escherichia coli and Staphylococcus aureus increased (p < 0.05) by increasing the HBE from 0 to 2% (v/v). No significant differences (p > 0.05) in inhibition zones were observed between films containing from 2 to 4% (v/v) HBE against both bacteria. Therefore, the AG-HBE film with 2% (v/v) HBE was considered as the optimal film due to its good TS (14.47 MPa) and EB% (41.13%), as well as its antibacterial properties. In conclusion, the alginate film incorporated with HBE has potential to be used in the active secondary food packaging application.