Abstract:
Microgreens are innovative vegetable products whose production and consumption are
gaining popularity globally thanks to their recognized nutraceutical properties. To date, the effects
of lighting conditions and growing substrate on the performances of Brassica carinata microgreens
(indigenous to Africa) remain underexplored. The present study aimed at providing insights into
the influence of different lighting treatments provided by LEDs, namely monochromatic blue (B),
red (R), cool white (W) and a combination of three color diodes (B + R + W), and substrates (cocopeat,
sand and cocopeat–sand mix (v/v) (1:1)) on the growth, yield and bioactive compounds of B. carinata
microgreens. Seeds were germinated in dark chambers and cultivated in growth chambers
equipped with LED lighting systems for 14 days under a fixed light intensity of 160 ± 2.5 µmol m−2
s−1 and photoperiod of 12 h d−1. The best performances were associated with the spectrum that
combined B + R + W LEDs and with substrate resulting from the cocopeat–sand mix, including the
highest yield (19.19 g plant−1), plant height (9.94 cm), leaf area (68.11 mm2) and canopy cover (55.9%).
Enhanced carotenoid and flavonoid contents were obtained with B + R + W LEDs, while the B LED
increased the total amount of chlorophyll (11,880 mg kg−1). For plants grown under B + R + W LEDs
in cocopeat, high nitrate levels were observed. Our results demonstrate that substrate and light
environment interact to influence the growth, yield and concentration of bioactive compounds of B.
carinata microgreens.
Keywords: African indigenous vegetables; healthy diets; light quality; functional foods;
nutraceutical; phytochemical
