Eunice Lua Hanry1 and Noumie Surugau1
1Seaweed Research Unit, Faculty of Science and Natural Resources, Universiti Malaysia Sabah,
88400 Kota Kinabalu, Sabah, Malaysia
Recently, seaweed and its hydrocolloids were being promoted as ingredient for biodegradable plastics. In this study, bioplastics were developed from whole seaweed (Kappaphycus
alvarezii) biomass (WS), semi-refined carrageenan (SRC) and refined carrageenan (RC). To enhance their properties, they were dyed using butterfly pea flower (Clitoria ternatea L.),
bougainvillea flower; and dragon fruit (Hylocereus polyrhizus) peel extracts. The bioplastics
development employed material-to-water ratio of 1:50; 2% (v/v) glycerol as plasticizer and 5% (v/v) natural dye. As results, the bioplastics were 0.03 – 0.100 mm in thickness which is in the
range of commercial food packaging. Without dye, the WS, SRC and RC bioplastics has opacity (mm-1) of 4.14 ± 0.45, 3.50 ± 0.30 and 1.63 ± 0.31, respectively; meanwhile colour
difference (∆E) were 29.6 ± 0.1, 14.2 ± 0.1 and 6.4 ± 0.1, respectively. RC bioplastic has the highest tensile strength (12.80 ± 0.90 MPa) and elongation-at-break (25.7 ± 0.5 %), followed
by SRC (8.0 ± 0.4 MPa, 21.3 ± 0.6%) and WS (5.4 ± 0.7 MPa, 17.9 ± 1.0 %). No significant difference in water vapour permeability (WVP); WS degraded the fastest with all bioplastics
fully degraded after 18 days; and shelf life (at 25oC, 56% RH) up to 17 weeks. For the dyed bioplastics, the natural dye blended well into the natural colour of base material resulting in
attractive shade. Mechanical properties, WVP and biodegradability were not significantly affected but shelf-life was 20 – 30% longer. Seaweed bioplastics have a potential as green
alternative for single-use non-degradable food packaging.