Development of pectin-gelatin biopolymer films with DES based Chlorella vulgaris extracts as plasticizers for enhanced UV-blocking, antioxidant, and antimicrobial food packaging application
Gülşah Karabulut, Gülden Gökşen
Abstract
The growing demand for alternatives to synthetic plastic in food packaging has driven the development of multifunctional biopolymer films. This study explores the integration of Deep Eutectic Solvents (DES) and bioactive compounds from Chlorella vulgaris into pectin-gelatin films to enhance their mechanical, bioactive, and barrier properties for active food packaging applications. Films were prepared using glycerol, DES, or DES enriched with C. vulgaris (ADES) as plasticizers at 20 % and 40 % concentrations. ADES films exhibited the most significant enhancements, with tensile strength increasing by 35 % and elongation at break by 22 % compared to DES films. FTIR and XRD data revealed enhanced hydrogen bonding and crystallinity due to interactions between C. vulgaris bioactives and the polymer matrix. Optical analysis revealed that glycerol-based films exhibited the highest transparency but provided minimal UV-blocking. In contrast, DES-based films showed moderate opacity and UV protection, while ADES-based films—enriched with C. vulgaris bioactives—displayed the highest opacity and the most effective UV-blocking capability. ADES films demonstrated superior antioxidant activity and total phenolic content. Antimicrobial assays showed broad-spectrum activity, with inhibition zones against S. aureus and E. coli increasing by 20 % and 80 % in 40AD films. Food application tests on chicken meat highlighted the efficacy of ADES films in maintaining pH stability and reducing lipid oxidation by 41 %. Moreover, microbial growth was significantly suppressed, with total mesophilic bacteria reduced to 5.59 log CFU/g after 7 days. These findings demonstrate the potential of ADES-based films as bioactive packaging materials, offering multifunctionality and improved shelf life for perishable foods.