Bio-based film development: Harnessing alginate and fucoidan extracted from Ascophyllum nodosum with glycerol and choline chloride-based solvent

Abstract

Development of bioactive films and food coverings from renewable resources has major advantages for reducing reliance on plastic materials and increasing the shelf life of associated food products. This study assessed the development of such food covering films using combined alginate and fucoidan extracted from the brown seaweed Ascophyllum nodosum. A solvent containing glycerol and choline chloride was used to extract fucoidan before sodium carbonate was used for alginate extraction. The extracted fucoidan contained approximately 42.2% glycerol and was used as a substitution for glycerol when developing alginate films through 0, 50 and 100% glycerol supplementation. Two sets of films were produced using either crudely extracted or analytical grade alginate. These films were tested for suitability within food covering applications through tensile testing, moisture barrier analyses, antibacterial, and antioxidative assays. We show that glycerol supplementation with fucoidan had minimal effect on tensile properties at 50% glycerol supplementation, though it decreased significantly at 100% glycerol supplementation. Furthermore, the glycerol supplementation with fucoidan significantly reduced each film's moisture barrier properties, allowing for higher moisture transfer through the films. The re-addition of fucoidan into the alginate films also had little effect on the oxygen scavenging abilities of the films but maintained a substantial hydroxyl scavenging capacity of 48.09 ± 0.3% from crude alginate films with 100% glycerol supplementation when compared to 7.29 ± 3.42% neat alginate films without fucoidan supplementation. Our results show that combining alginate and fucoidan is an effective strategy to produce bioactive films for food coverings and facilitates solvent recycling, while reducing alginate polymer development costs.