Starch-based edible packaging: rheological, thermal, mechanical, microstructural, and barrier properties - a review

The alarming adverse impacts of fossil fuel-based packaging materials led to the development of sustainable packaging materials from renewable sources that are readily biodegradable. To reduce the burden of packaging material's end-use, edible packaging in the form of films and coatings is a promising alternative to protect fresh food by maintaining quality and safety, and it can also be used as a delivery vehicle for essential nutrients. Starch, a widely explored plant polysaccharide, might be the best candidate on the list of biodegradable materials due to its natural abundance, thermoplasticity, and, above all, inexpensiveness. However, starch exhibits some limitations as a stand-alone film material, such as inferior barrier and mechanical properties compared to its commercial plastic counterparts. Various approaches have been employed to make it viable for industrial adaptations, including plasticization, co-biopolymer blending, and the incorporation of active additives and nanomaterials. Accordingly, the effect of such strategies on the properties of starch-based edible films and coatings has been discussed in this review. Overall, the review presents state-of-the-art information about important properties pertaining to starch-based edible films and coatings, including rheological, thermal, mechanical, microstructural, and barrier properties. The microstructures of starch-based edible films are shown in the following micrographs. A well-defined distribution of edible oils and cellulose nanoparticles on the starch surface can be clearly visualized.