Facile fabrication of thermostable and colorimetric starch-based waterproof coating with edible organic materials

With the attention to pollution and human health, nontoxic food grade superhydrophobic coating as a strategy to reduce food waste has aroused wide interest. Herein, a food grade colorimetric starch-based waterproof coating was achieved using starch nanoparticle (SNP), stearic acid (STA) and anthocyanin. The as-prepared coating exhibited considerable thermostability and remarkable water repellency due to the low-surface-energy pomegranate pulp-like micro/nanostructure assembled by STA and SNP. The certain mechanical and chemical durability, prominent self-cleaning property and liquid food repellency in the coating had been thoroughly verified. Additionally, anthocyanin was creatively introduced to the coating via SNP loading, which endowed the coating with color response to different pH solutions. Thus, the coating is applicable to freshness monitoring without being disabled by water. This thermostable and colorimetric starch-based waterproof coating shows promising application prospects in advanced bio-based food-contact material field.