Evaluation of Bioactive Compounds and Antioxidant Activity of Green and Red Kale (Brassica oleracea L. var. acephala) Microgreens Grown Under White, Red, and Blue LED Combinations

Abstract

Microgreens have great potential for improving the nutritional value of human diets, as well as constituting a promising dietary option for preventing chronic disease. Light-emitting diodes (LEDs) are commercially used as a light source to improve the growth of microgreens, as well as nutrient and bioactive compound accumulation. Here, we provide the first report of the phenolic compound, chlorophyll and carotenoid pigment, and dietary fiber contents of red and green kale microgreens grown in a growth chamber under white LEDs combined with red or blue light. Significant differences in the response of phytocompounds between white light and its combination with blue or red LEDs were determined. These studies showed that a combination of white and blue LEDs positively influenced the accumulation of phenolic compounds, which consequently determined high antioxidant activity. On the contrary, the white LED lights were the most suitable for the accumulation of carotenoids and chlorophylls, including chlorophyll a and b, and Klason lignin. These results suggest that the use of a combination of white light with blue or red light can increase the concentration of phenolic compounds and dietary fiber in red and green kale microgreens and thus may enhance their health-promoting potential.