Natural Dyes Used as Organic Coatings UV Protecting for Food Packages
Nowadays, the use of biodegradable and bio-derived plastics such as poly(lactic acid) (PLA) and cellulose in food packaging applications are replacing the use of different and more conventional oil-derived polymers that are much more expensive and unsuitable for the environment. However, their high transparency to ultraviolet (UV) radiation limits their current commercialization. Therefore, this study focuses on the deposition of organic thin films on commercial PLA and cellulose in order to enhance their performance, in particular for UV shielding. Coatings with different natural and biocompatible (edible) molecules, quinine and p-Coumaric acid, dispersed in different matrices are deposited by comparing different deposition techniques such as spray coating and spin coating. Morphological characterizations are carried out with atomic force microscopy (AFM) and scanning electron microscopy (SEM), with spectroscopic characterizations performed by light transmission measurements. Our results show that it is possible to enhance the UV protection of packaging using a suitable deposition with these biocompatible materials.