The effects of UV-C irradiation on postharvest quality of tomatoes (Solanum lycopersicum)

Tomato (Solanum lycopersicum) is globally one of the most important vegetables. It is an important source of antioxidants in the human diet. However, the loss of quality at postharvest is a major issue limiting the shelf-life of tomatoes. Irradiation is a non-thermal technology that eliminates pathogens and extends the shelf-life of fruit and vegetables. This study investigated the potential of UV-C irradiation in delaying the ripening process and enhancing the overall quality of tomatoes. Tomatoes ('Henry's Beauts'), harvested at mature pink stage, were irradiated at 0, 208.2 and 969.8 µW cm^-2, three replications of 5 fruits replicate^-1 were used. The radiation dose was measured with a portable digital radiometer. After irradiation, the fruits were stored at 20°C for 4, 8, 12 and 16 d. The total soluble solids (TSS), fruit colour and total carotenoids were determined. UV-C irradiation had no significant effect on the TSS, however, measured and calculated fruit colour parameters (a*, L and hue angle) were significantly influenced by irradiation treatments. Exposing fruit to 969.8 µW cm^-2 delayed the colour development and ripening process. Irradiation had significant effect on the content of carotenoids. Although fruit exposed to 969.8 µW cm^-2 had better overall quality, the development of lesions on exocarp possibly due to high irradiation intensity remains a concern. This study showed the potential of UV-C irradiation treatment as a postharvest tool for the management of tomatoes. Further research aimed at understanding the mechanism of action used by UV-C irradiation is warranted.