Supplemental preharvest application of low-intensity red or blue LED light to improve the nutritional quality of rocket (Eruca sativa Mill) leaves

Abstract

Light quality affects the chemical composition of leafy vegetables through the regulation of primary and secondary metabolism. This study aimed to evaluate the effect of supplemental radiation provided by red and blue LED light on the phytochemical and mineral composition of rocket (Eruca sativa Mill) leaves. Supplemental radiation of approximately 40 µmol m-2 s-1 was added to a background of low sunlight intensity for 4 hours each day (from 15 to 19 h). The LED treatment was applied as an End-of-Production treatment for 14 days before harvest in greenhouse-grown rocket plants. Rocket leaves treated with red light showed an increase in Ca, P, carotenoids, anthocyanins and phenolic compounds, and no changes in chlorophyll, proteins and sugars. The supplemental radiation used in the blue light treatment was insufficient, as no differences were observed in any of the metabolites studied compared to control plants. The results show that supplementation with low-intensity red light is an End-of-Production treatment that could improve the nutritional quality of rocket leaves.