Trends and challenges of starch-based foams for use as food packaging and food container

ABSTRACT

Background: Expanded polystyrene (EPS), an inexpensive and widely available polymer, has been extensively employed in foam packaging. However, EPS-based foams cause environmental problems because they are non-biodegradable and little recycled. Therefore, developing foams from renewable sources for application in biodegradable packaging for food and express food delivery is essential to tackle pollution issues of synthetic plastics. Scope and approach: Starch is a renewable, abundant, and low-cost source with thermoplastic properties. For this reason, starch has been used as raw material to develop foams for packaging. This review emphasizes different strategies for improving the mechanical properties, processibility, and antimicrobial activity of starch-based foams and for decreasing their sensitivity to humidity, aiming at employing them as competitive replacement for EPS in packaging. Key findings and conclusions: Starch source, foaming process conditions, plasticizer concentration, fiber type and concentration, and addition of other polymers to form blends can affect the properties and morphology of biodegradable foams, so these factors should be better studied and optimized. Agroindustrial residues have become an interesting alternative to reduce the cost of foams, aiming at a competitive replacement for EPS. Few works have been developed on bioactive starch-based foams. Searching for starch-based foams with antiviral properties against SARS-Cov-2 is also necessary. © 2021 Elsevier Ltd