Light Intensity and Wavelength Modulate Antioxidant Secondary Metabolites in Embryonic Axis of Chickpea Sprouts

Chickpea (Cicer arietinum L.) is a highly nutritious legume with significant potential as a food plant. With the advent of climate change and the challenge of feeding a growing population, strategies to produce high-nutrient crops are of utmost importance. In this context, this study describes how light intensity and wavelength affect the embryonic axis of chickpea sprout metabolism, using untargeted metabolomics. Chickpea sprouts were grown under varying light wavelengths (red-650, green-550, and blue-450 nm) at two intensities (75 and 275 µmol·m^-2·s^-1). Analyses were restricted to the embryonic axis (hypocotyl), excluding the cotyledons, which are a reserve-rich tissue. Results showed that high-intensity red light (RH) increased phenolic content by more than 300% compared to controls. Green and blue light treatments significantly increased the protein content by more than twice that of the dark control. Antioxidant activity was significantly higher in sprouts grown under high-intensity blue light (BH). Additionally, the results suggested that pathway regulation is affected not only by wavelength but also by light intensity, with greater significance and effect under BH and RH treatments in isoflavonoid biosynthesis. High quercetin concentration found under BH is hypothesized to explain the high antioxidant activity when compared to the rest. For instance, these findings highlight the potential of light manipulation to modulate and enhance the nutritional and functional qualities of chickpea sprouts' embryonic axis, contributing to food security and human health. Further studies need to be conducted to answer whether these metabolite changes directly translate to the nutritional quality of the whole edible sprouts.