Current Review of the Modulatory Effects of LED Lights on Photosynthesis of Secondary Metabolites and Future Perspectives of Microgreen Vegetables

Abstract

Light-emitting diode (LED) lights have recently been applied in controlled environment agriculture toward growing vegetables of various assortments, including microgreens. Spectral qualities of LED light on photosynthesis in microgreens are currently being studied for their ease of spectral optimization and high photosynthetic efficiency. This review aims to summarize the most recent discoveries and advances in specific phytochemical biosyntheses modulated by LED and other conventional lighting, to identify research gaps, and to provide future perspectives in this emerging multidisciplinary field of research and development. Specific emphasis was made on the effect of light spectral qualities on the biosynthesis of phenolics, carotenoids, and glucosinolates, as these phytochemicals are known for their antioxidant, anti-inflammatory effects, and many health benefits. Future perspectives on enhancing biosynthesis of these bioactives using the rapidly progressing LED light technology are further discussed.

Microgreens: Consumer sensory perception and acceptance of an emerging functional food crop

“…Additionally, these data show that there is high variability in how individuals perceive the flavor and specific sensory attributes of arugula, and therefore selection of arugula microgreens for consumption should be more personalized for consumer acceptability. Higher concentrations of these compounds have been observed in young plants compared with the mature plant (Drewnowski & Gomez‐Carneros, 2000), an important factor when considering growing practices (e.g., modulation of LED lighting) for enhancing the levels of these health‐promoting compounds (Alrifai et al., 2019), particularly with respect to consumer acceptability of microgreens. Though not evaluated in the present study, research is currently underway in our laboratory to examine the bioactive compounds present in the six microgreens evaluated in the present study, and the influence of maturity.…”

“…Various preharvest factors may not only influence plant growth but also their levels of micronutrients and bioactive compounds. Considerations should include seed sowing rate due to competition for resources (e.g., nutrients), the use of fertilizers or lack thereof and their nutrient contents, biofortification, and lighting types, wavelengths, and dosage which can influence plant secondary metabolite production and thus the levels of bioactive compounds (Alrifai, Hao, Marcone, & Tsao, 2019; Choe et al., 2018; Mir et al., 2017).…”

Microgreen nutrition, food safety, and shelf life: A review

“…Light quality affects many aspects of plant growth, morphology, color, flavor, and nutrition (Kyriacou et al., ). Alrifai, Hao, Marcone, and Tsao () explains that red, blue, and combined red plus blue light are more effective than white light and other wavelengths for enhancing photosynthesis and regulating plant metabolism. Samuolienė et al.…”

Phenolic Constitution, Phytochemical and Macronutrient Content in Three Species of Microgreens as Modulated by Natural Fiber and Synthetic Substrates

“…Although several studies revealed that variation in microgreens' content of bioactive compounds is based on several pre-harvest factors such as genetic material (i.e., species), conditions of cultivation and light parameters (i.e., spectral quality and intensity), additional variables have also been implicated in shaping microgreens' nutritive and phytochemical composition, including nutrition/biofortification and choice of growth medium [4,10,[12][13][14][15][16][17][18][19][20][21]. Notwithstanding the short crop cycle, special attention must be placed on the selection of growth media for microgreens, which represents one of the most important factors in the production process influencing microgreens quality [22].…”