Effects of continuous red light and short daily UV exposure during postharvest on carotenoid concentration and antioxidant capacity in stored tomatoes

- Red light and red light with UV radiation accelerates ripening of tomato fruit.
- Red light treatments increase antioxidant activity in tomato fruit.
- Red light represents the best treatments for stored tomato fruit by cost consideration.

Due to their health benefits, high concentrations of antioxidative compounds in vegetables and fruit are important for end-consumers. The aim of this research was to investigate the effects of continuous red light and short periods of daily ultraviolet (UV) radiation on the postharvest quality of green tomatoes. Green tomatoes were exposed for 30 min to UV radiation, continuous red light or a combination of both for up to 20 d. Non-treated (control) fruit ripened within 15 d while fruit exposed to red light and a combination of red light with UV radiation required five days less to reach the same maturity level. In addition, the exposure to red light alone or in combination with UV raised concentrations of lycopene, ß-carotene, total flavonoids and phenolics. This possibility to steer the concentrations of health-promoting antioxidants through light treatments is a safe method to increase fruit quality according to customer wishes and demands.