Abstract
A mild heat stress in the form of a hot water treatment applied to tomato fruit was shown to promote the synthesis of beneficial antioxidants, such as lycopene, and hence can enhance red color development. We hypothesized that hot water treatment can also improve the uniformity of color development. Mature-green ‘Soraya’, ‘Tasti Lee’, ‘Florida 47’, ‘Biltmore’, and ‘Crown Jewel’ tomatoes were immersed in water at 25 °C or 52 °C for 5 min, followed by treatment with 100 ppm ethylene for 48 h at 20 °C. Ripeness was evaluated during storage in air at 20 °C by measuring color (CIE a*) on the blossom end of the fruit until a* reached a stable value. The standard deviation of the a* value among fruit was used as a measurement of color uniformity. The hot water treatment improved color uniformity (i.e., reduced the standard deviation of the a* value), especially at the pink developmental stage for all cultivars. In the case of ‘Florida 47’, the effect varied within seasons.