Different methods for chlorophyll removal were used for betel leaf ethanolic extracts (BLEE). Chlorophyll content, color, and antioxidant and antibacterial activities of the resulting extracts were examined. Sedimentation process remarkably reduced the chlorophyll content and color of BLEE (p < 0.05), while antioxidant and antibacterial activities were enhanced (p < 0.05). Polyphenol content and bioactivities of the extracts dechlorophyllized using organic solvents varied (p < 0.05). Antibacterial efficacy of BLEE dechlorophyllized by the sedimentation method (BLEE-SED) depended on concentrations. Lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of BLEE-SED toward 4 bacteria were obtained, compared to other extracts. Lower microbiological and chemical changes were achieved when Nile tilapia fillets were treated with BLEE-SED at 400 and 600 ppm after 12 days of storage at 4 °C. Therefore, sedimentation as a green process could be adopted for preparing a safe BLEE with augmented bioactivities and pale color, which could extend shelf-life of refrigerated Nile tilapia fillets.
Gelatin/chitosan solutions incorporated with betel leaf ethanolic extract (BLEE) at varying concentrations were electrospun on polylactic acid (PLA) films. Nanofibers with different morphologies, as indicated by scanning electron microscopy (SEM), were formed after solutions of gelatin/chitosan with and without BLEE were electrospun on PLA films at a constant voltage (25 kV) and a feed rate of 0.4 mL/h. Beaded gelatin/chitosan nanofibers (GC/NF) were found, particularly when high concentrations of BLEE were encapsulated. PLA films coated with GC/NF, and with BLEE added, showed antioxidant and antibacterial activities, which were augmented by increasing BLEE concentrations. Lower water vapor permeability and enhanced mechanical properties were achieved for GC/NF-coated PLA film (p < 0.05). Microbial growth and lipid oxidation of Nile tilapia slices packaged in PLA film coated with GC/NF containing 2% BLEE were more retarded than those packaged in low-density polyethylene (LDPE) bags over refrigerated storage of 12 days. Based on microbial limits, the shelf-life was escalated to 9 days, while the control had a shelf-life of 3 days. Therefore, such a novel film/bag could be a promising active packaging for foods.