State of the Art and Elucidation of Postharvest LED Lighting on the Metabolism of Brassica Sprouts

Abstract

Brassicaceae sprouts are important sources of vitamins, phenolic compounds, minerals, glucosinolates, and isothiocyanates. LEDs illumination have been demonstrated to increase yield and the phytochemical content of young plants. In the present work, rocket, radish, and tatsoi seeds were germinated in darkness for 7 days at 20 °C and 90% RH. After harvesting, sprouts were stored for 5 days at 5 °C under different LEDs treatments: White, Blue, Green, Orange, and Red. Darkness was used as control. The respiration rate and the sulforaphane content were monitored as a reference of the primary and secondary metabolism changes to evaluate the influence of LEDs. The application of Blue and Green LEDs increased the CO2 emission by ~25–45% compared to Darkness while no C2H4 emission was detected. The biosynthesis of sulforaphane was also increased by ~15–25%, under different wavelengths, although a clear tendency was not found among species. The state of the art of this research field was reviewed to elucidate the knowledge on it. Conclusively, the primary and secondary metabolism of plants, specifically in sprouts, can be stimulated using postharvest LED lighting.