Effects of UV-C irradiation on lipid peroxidation markers during ripening of tomato (Lycopersicon esculentum L.) fruits

Abstract

The effects of a hormic dose (3.7 kJ m⁻²) of UV-C (254 nm) on changes in fruit membrane lipids perox-idation markers during storage were determined using tomato (Lycopersicon esculentum L. cv. Trust) fruit. There were two distinct response phases following the treatment. A significant induction of lipid peroxidation markers (lipofuscin-like compounds, malondialdehyde, aldehydes, pentane, ethane, hydrogen peroxide, and efflux of elec-trolytes including potassium and calcium) occurred within the first 5 days. This induction suggests that the cell mem-brane was the primary target of UV-C irradiation. After this period, the level of all of these peroxidation markers become lower in UV-C-treated fruit than in control fruit, suggesting the induction of a defense or repair mechanism, probably involving production of antioxidants and activation of antioxidative enzyme. Within the second phase, any changes in lipid peroxidation activity reflected the fruit ripening / senescence process rather than the UV-C effect.