An Experimental and Educational Framework for Nonenzymatic Polyphenol Conversion: Bridging Molecular Food Science and Materials Technology through Organic Chemistry

The need to establish an effective connection between fundamental sciences—such as chemistry, physics, and mathematics—and applied disciplines, including gastronomy, is increasingly evident from high school to the workplace. In this study, an organic chemistry methodology is employed as an educational tool within the field of food sciences. The synthesis of a simple tannin, consisting of a mixture of gallic acid oligomers and polymers, is designed to illustrate the key reactions involved in the natural maturation of polyphenols in fruits and vegetable skins. These processes include radical activation of phenolic units followed by condensation through aryl C–C and O–C bond formation. The chemical transformations of the polyphenols were characterized by benchtop NMR spectroscopy, monitoring the signals of both the phenolic -OH protons (in acetonitrile) and the aromatic protons to track structural changes and the related reaction progress. The reaction is readily interpretable through observable macroscopic color changes, and this straightforward transformation pathway can be effectively integrated into broader educational frameworks related to organic materials technology. Polyphenols have been then stylishly exploited to produce organic coatings over different biological porous materials, revealing that protein backbones are generally intensely amenable to nonenzymatic polyphenol formation.