LED Lights Influenced Glucosinolates and Carotenoid Contents and Antibacterial Activities in Red Chinese Cabbage ( Brassica rapa L. ssp. pekinensis ) Microgreens

Objectives The aim of this study was to investigate how different LED wavelengths, blue (450 nm), red (660 nm), and white (380-780 nm), influence the accumulation of glucosinolates and carotenoids in Chinese cabbage ( Brassica rapa L. ssp. pekinensis ) microgreens. Additionally, the study sought to evaluate how these spectral treatments affect the antibacterial activities of the microgreens against methicillin-resistant Pseudomonas aeruginosa strains. Methods Chinese cabbage microgreens were cultivated for 10 days under controlled environmental conditions using three LED light treatments: blue, red, and white. Phytochemical profiling, specifically glucosinolate and carotenoid quantification, was performed using high-performance liquid chromatography. Antibacterial activity was evaluated through disc diffusion assays against methicillin-resistant Pseudomonas aeruginosa to assess differences among LED-treated samples. Results Red LED irradiation significantly increased the total glucosinolate content in microgreens, whereas blue LED treatment resulted in the highest accumulation of total carotenoids. Red LED-treated microgreens exhibited the strongest antibacterial activity against multidrug-resistant Pseudomonas aeruginosa , suggesting a potential association between glucosinolate levels and antimicrobial performance. Conversely, blue LED-treated samples, despite containing higher carotenoid concentrations, showed comparatively weaker antibacterial effects. Conclusion These findings demonstrate that LED spectral quality can be strategically manipulated to regulate key phytochemicals in Brassica microgreens. Red LED light enhances glucosinolate accumulation and antimicrobial activity, while blue LED light promotes carotenoid production but not antibacterial efficacy. Overall, the study offers valuable insights into optimizing functional phytochemical production and improving the antimicrobial potential of microgreens for functional foods and controlled-environment agriculture.