The application of UV-C irradiation followed by storage in continuous low level ethylene atmosphere to delay the ripening of mature green tomatoes

Mature green tomatoes (Solanum lycopersicum ‘Neang Pich’) were exposed to 0, 3.1, 7.1, 10.5 and 13.6 kJ m^-2 UV-C irradiation at 20°C. After treatment, tomatoes were stored in continuous air containing either <0.005 or 0.1 μL L^-1 ethylene at 20°C and 100% RH for up to 11 days. The untreated fruit (0 kJ m^-2 UV-C) ripened significantly faster than UV-C treatments in both storage conditions. All UV-C treatments followed by storage at either <0.005 and 0.1 μL L^-1 ethylene had significantly slower ethylene production rates throughout the ripening period. There was no difference between treatments in fruit TSS, TA and, TSS/TA ratio. After storage, fruit treated with 10.5 and 13.6 kJ m^-2 UV-C were significantly firmer than untreated fruits for both storage conditions. Overall, tomatoes stored at <0.005 μL L^-1 ethylene were significantly firmer and had lower TSS/TA ratio than fruits stored at 0.1 μL L^-1 ethylene. These results show that UV-C treatment delayed ripening of tomatoes in the presence of low level of ethylene during storage. In the absence of added ethylene, UV-C treatment resulted in firmer fruit with higher TSS and TSS/TA ratios. This new treatment could be used to extend the shelf-life of mature green tomatoes through the supply chain.