The effect of Blue:Red light proportion on germination parameters, growth attributes, and quality of borage sprouts

Sprouts are functional foods rich in compounds beneficial to human health, that deserve enhanced study, especially those from wild and voluntary species. Among these, borage sprouts have been reported to have good nutritional traits. This work aimed to investigate whether borage sprouts quality could be improved through the modulation of light wavelengths. Borage seeds were sown under seven light treatments with the total incident photon flux density (PFD) of 200 µmol m−2 s−1 and 12/12 h light/dark photoperiod: monochromatic blue (B100); monochromatic red (R100); blue + red light at three different proportions (75 % of blue and 25 % of red, B75-R25; 50 % of blue and 50 % of red, B50-R50; 25 % of blue and 75 % of red; B25-R75), along with a wider light spectrum (WIDE) and no light (DARK). The sprouts were harvested at the fully expanded cotyledon stage, 7 days after sowing, and frozen for chemical analysis. The results revealed that borage is an interesting species for sprouting as it requires minimal inputs for germination, and it is extremely suitable for indoor cultivation under LED lights. The light treatments affected some growth parameters (lengths and cotyledons shape) and the nutritional traits (i.e. sugars, chlorophylls, and vitamin C content). Borage sprouts showed suitable growth parameters (biomass production and appearence) in DARK, WIDE, R100, and B100 (monochromatic lights), whereas the most valuable nutritional quality (high level of total sugars and vitamin C) was obtained with a dichromatic blue:red light, mainly with prevalence of blue (i.e., B75-R25).