Hydroponic technologies have increased the cultivated area under greenhouses covered with UV filter polyethylene film. However, there is a concern about the antioxidant contents of lettuces produced under these systems.
A new study compares the antioxidant contents of green and red leaf lettuces produced in two hydroponic systems in a greenhouse, against the ones produced with the conventional cultivation system by Colombian farmers. According to the researchers, the best results were obtained in the conventional cultivation.
"These results suggest a detrimental effect of the greenhouse covered with UV filter polyethylene film in the antioxidant production of lettuce", the researchers say. "Finally, red leaf lettuce showed better antioxidant capacity independent of the cultivation system."
Access the full study at ResearchGate. If you're interested in more figures, this study explores organic acids, sulphate, total nitrogen and total chlorophyll contents of two lettuce cultivars grown hydroponically using nutrient solutions of variable macrocation ratios.