The potential use of the UV-A and UV-B to improve tomato quality and preference for consumers

Solanum lycopersicum L. is among the healthiest fruits/vegetables due to its richness in bioactive compounds. However, its fruits from off-season (usually obtained in greenhouses that block UV-rays) have lower reputation than the ones of in-season/field productions. We hypothesise that moderate UV-A/UV-B irradiation during fruit development is able to improve its bioactive compounds and sensorial attributes, increasing its healthy properties. We supplemented for 30 days 'MicroTom' fruiting plants with two daily doses of UV-A (1 or 4 h) and UV-B (2 or 5 min). Irradiated plants showed higher ripening synchronization and produced more and smaller fruits. UV-A irradiation stimulated the fruit's antioxidant capacity, and the antiradical activity by the accumulation of phenolic compounds including the flavonoids. Only the UV-A1 h condition promoted the accumulation of ortho-diphenols in tomato fruits. Regarding the consumers' preference for aroma/taste, a consumers' panel test ranked the tomatoes as UV-A1 h, UVA 4 h, Control, UV-B 5 min and UV-B 2 min. We conclude that the supplementation of UV-A during pre-harvest is particularly effective in increasing ripening synchronization and fruit's nutritional properties, potentially making these fruits more appealing to consumers.