Post-harvest alterations in quality and health-related parameters of cherry tomatoes at different maturity stages following irradiation with red and blue LED lights

Green-mature and turning cherry tomatoes (Solanum lycopersicum L.) of a red (‘Cherry Little Wonder’) and a yellow (‘Goldilocks’) cultivar (cv) were illuminated, post-harvest, with either red (118 µmol m–2 s – 1 at 638 nm) or blue LED light (118 µmol m–2 s – 1 at 454 nm) for 48 h and subsequently stored for up to 21 days at room temperature. The effects of the treatments on colour, firmness, sugars and carotenoids were evaluated throughout storage. The light treatments did not have any effect on firmness and mass; however, light exposure, particularly red light, enhanced the a* colour component of the red cv significantly; similarly, colour coordinate b* of the yellow cv, treated at both stages of development, was significantly enhanced by both light treatments, resulting in visually redder and yellower tomatoes, respectively. These effects were more so observed on green-mature than on turning fruit. In addition, the treatments significantly increased lycopene concentrations in the red cv at both ripening stages, and β-carotene concentrations in both, the yellow and red cv treated at the green-mature stage. Total soluble solids (%TSS) also increased significantly following treatment. Findings reported suggest that illuminating tomato fruit with LED lights at the green-mature stage enhances colour development and the concentration of sugars, pigments and other health-related compounds without significantly affecting fruit mass and firmness.