Food Antioxidants: Chemical Insights at the Molecular Level

In this review, we briefly summarize the reliability of the density functionaltheory (DFT)-based methods to accurately predict the main antioxidantproperties and the reaction mechanisms involved in the free radical–scavenging reactions of chemical compounds present in food. The analyzedproperties are the bond dissociation energies, in particular those involvingOH bonds, electron transfer enthalpies, adiabatic ionization potentials,and proton affinities. The reaction mechanisms are hydrogen-atom transfer,proton-coupled electron transfer, radical adduct formation, single electrontransfer, sequential electron proton transfer, proton-loss electron transfer,and proton-loss hydrogen-atom transfer. Furthermore, the chelating abilityof these compounds and its role in decreasing or inhibiting the oxidativestress induced by Fe(III) and Cu(II) are considered. Comparisons betweentheoretical and experimental data confirm that modern theoretical tools arenot only able to explain controversial experimental facts but also to predictchemical behavior.