Producing novel edible films from semi refined carrageenan (SRC) and ulvan polysaccharides for potential food applications

Edible films were developed from seaweed polysaccharides (Kappaphycus alvarezii and Ulva fasciata). The total extracted yield of semi refined carrageenan (SRC) and ulvan polysaccharide was 31.55%, and 28.86%, with total carbohydrate being 78.08% and 82.43% in SRC and ulvan polysaccharides. Results of viscometric studies revealed molecular weight to be 210 kDa and 72 kDa for SRC and ulvan polysaccharides. Proton NMR studies showed presence of anhydro-D-galactopyranose and glucosidic linkages in SRC, while ulvan polysaccharide had rhamnose-3-sulfate, glucosyl and beta-D-glucuronic acid. Three different films developed from SRC and ulvan polysaccharides [SRC, ulvan polysaccharide and combination of SRC and ulvan polysaccharide films] with glycerol. FT-IR spectra confirmed functional group of all the edible films which corresponds with NMR results. Water vapor permeability of films indicated a range of 7.82 to 9.96 x 10(-8) gm(-1) s(-1) Pa-1 with high tensile strength varying between 36.78 and 49.12 MPa. Results on antioxidant activity indicated a strong hydroxyl radical scavenging activity detected in ulvan polysaccharide based film, while metal ion chelating activity was higher in films with a combination of SRC and ulvan polysaccharides. Further, low molecular weight films had better antioxidant activity, while high molecular weight films possessed good mechanical properties. (C) 2018 Elsevier B.V. All rights reserved.