Effects of LED Light Exposure on Lutein and Bioactive Compounds in Nasturtium Flowers (Tropaeolum majus L.)

Abstract

This study evaluated the impact of red LED light exposure time on the biosynthesis of bioactive compounds in yellow, orange and red nasturtium (Tropaeolum majus L.) flowers. LED light treatments were applied during the growth phase with exposure times of 0, 2, 4 and 6 h. The analysis included antioxidant capacity, total carotenoids, total phenolics, anthocyanins, flavonoids and lutein (by HPLC). Yellow petals showed a significant increase in antioxidant capacity, reaching 39.66 μmol Trolox·g⁻¹ by ABTS after 3.23 h, a 68.91% increase compared to the control. Additionally, total carotenoids—reflecting the presence of lutein—peaked at 79.34 mg⋅g⁻¹ after 4.73 h more than double the content found in the untreated petals. In orange petals, total phenolics peaked at 128.13 mg AGE·100 g⁻¹ after 2.71 h, reflecting a 14% increase over untreated samples. Red petals exhibited the highest anthocyanin content, increasing from 1389.92 ± 8.86 mg 100 g⁻¹ (control) to 1973.10 mg 100g⁻¹ after 4.17 h, a 41.95% increase. These results highlight the potential of red LED light to enhance phytochemical production in nasturtium flowers, offering an innovative strategy to improve their nutritional and functional properties for food and nutraceutical applications.