Radiation-induced effects in the electron-beam irradiation of dietary flavonoids

The harmful effects of oxidative processes in living organisms can be reduced by the dietary intake of flavonoids, a class of phenolic compounds ubiquitous in plants and widely found in a number of fruits, vegetables and beverages. Many fruits and vegetables are treated by irradiation to solve preservation problems and a radical-induced degradation of nutrients, including polyphenols, may occur. The free radical chemistry of two abundant flavonoids in food, catechin and quercetin, have been investigated by using pulse radiolysis technique. The central role of the phenoxyl-type radical and the strong influence of the state of protonation of the compounds on the pathway of formation and decay of the corresponding oxidized radicals has been evidenced from the spectral properties and chemical reactivity of the radicals derived from the attack of several oxidizing species (.OH, N3.,SO4-.)