Sargassum inspired, optimized calcium alginate bioplastic composites for food packaging

Abstract

Plastic pollution, more specifically from food packaging and containers which account for the largest share of 36% of current plastic production, is one of the greatest threats to the natural environment and human health. Thus, the development of alternative renewable plastics are needed to complement a circular economy and reduce resource depletion. Seaweeds have been known to possess good film forming properties ideal for bioplastic production, and Sargassum natans-an invasive brown seaweed which has been inundating the shores of the Caribbean, has been shown to be an excellent candidate. This study presents, for the first time, the development of a novel optimized biodegradable alginate composite bioplastic as an alternative to traditional plastic packaging. The optimization process was carried out using Response Surface Methodology (RSM) resulting in a formulation of 6 wt% alginate, 0.263 wt% starch, 0.35 wt% CMC, 0.065 g/g sorbitol and 0.025 g/g PEG 200- with ultra-high oxygen barrier (OP - 0.2 cm3 μm m−2 d−1 kPa−1), good water vapor barrier (WVP - 2.18 × 10−12 g m/m2 s Pa) and high tensile modulus (E - 3.93 GPa)- with no migration of additives into a simulated aqueous food system in 10 days. Furthermore, composite films were found to fully degrade in 14 days and possessed better OP, higher WVP and comparable material properties to HDPE, PET and PLA. Ultimately, our results support alginate composite films as a viable alternative for food packaging best fitted for low moisture environments-encouraging the use of renewable materials for packaging innovation and supporting UNSDGs.