Can Light Spectrum Composition Increase Growth and Nutritional Quality of Linum usitatissimum L. Sprouts and Microgreens?

Abstract

Flaxseed could be suitable for obtaining high-quality sprouts and microgreens thanks to high amounts of nutrients and antioxidant, antidiabetic, and anticancer compound content in its seeds. Recent studies highlighted that seedling growth, nutritional compound, and secondary metabolite content can be strongly managed by regulation of the light spectrum used during germination. The present study intended to shed light on flaxseed as emerging and novel species for sprouts and microgreens and to evaluate the effect of light, with different spectrum compositions (100% blue, 100% red, 100% green, and red:green:blue—1:1:1) on the performance of flax microgreens and sprouts grown indoors under controlled conditions. Microgreens showed, compared to sprouts, a higher chlorophyll (+62.6%), carotenoid (+24.4%), and phenol content (+37.8%), antioxidant capacity (+25.1%) and a lower dry matter content (−30.7%). Besides, microgreens treated with 100% blue light were characterized by the highest content of flavonoids (2.48 mg CAE g−1 FW), total phenols (3.76 mg GAE g−1 FW), chlorogenic acid (1.10 mg g−1 FW), and antioxidant capacity (8.06 µmol TEAC g−1 FW). The paper demonstrates the feasibility of obtaining flax sprouts and microgreens indoors with a considerable antioxidant capacity and health-promoting compounds by modulating the light spectrum.

Supplemental UV-B Exposure Influences the Biomass and the Content of Bioactive Compounds in Linum usitatissimum L. Sprouts and Microgreens

“…The significantly higher dry matter content detected in flaxseed sprouts (+30%) compared to microgreens is in accordance with the recent report of Puccinelli et al [28] on the same species and cultivar, and it was likely due to the progressively higher water absorption during the growth of the seedlings. An increase in the moisture content of flaxseed sprouts following germination was observed also by Wang et al [26] and, in several amaranth cultivars, by Ebert et al [37].…”

“…Indeed, the fully expanded cotyledons, as well as the longer and thicker stems, of microgreens contributed to the greater fresh weight. A similar result was observed by Puccinelli et al [28] who detected a higher fresh biomass in flaxseed microgreens than in sprouts, irrespective of the different light spectrum compositions. The expected higher biomass of microgreens was also found in three Brassica oleracea L. cultivars, namely 'Broccolo Nero', 'Cavolo Lacinato Nero di Toscana', and 'Cavolo Broccolo Ramoso Calabrese', whose microgreens had weights on average +240, +125, and +100% compared to the sprouts' weights, respectively [35].…”

“…To date, no studies have studied the effect of UV-B supplementation on the productivity or nutraceutical quality of flaxseed sprouts and microgreens. Indeed, the recent paper of Puccinelli et al [28] investigated the influence of specific wavelengths of the PAR region on biomass production and phytochemical content in flaxseed sprouts and microgreens; however, the UV-B waveband was not included in the experimental design. Therefore, considering the well-known impact of UV-B radiation on plant bioactive compounds and growth performances, the present study aims to unravel the impact of pre-harvest UV-B exposure on the productivity of flaxseed sprouts and microgreens and to investigate whether controlled UV-B irradiation could increase the concentration of phenolic compounds, flavonoids, and photosynthetic pigments, and improve the antioxidant capacity.…”

Sprouts and Microgreens—Novel Food Sources for Healthy Diets

“…The sprouting of mungbean seeds increased total phenolic and flavonoid (TF) levels and the antioxidant activity (AA) when compared to ungerminated seeds (Table 3) [96]. Compared to sprouts, flaxseed (Linum usitatissimum) microgreens exhibited higher chlorophyll, carotenoid, and phenol contents, as well as higher antioxidant capacity [103].…”

“…The exposure of soybean (Glycine max) microgreens to monochromatic blue LED light and ultraviolet-A (UV-A) radiation led to significant increases in total phenolic and total flavonoid content, as compared with the white LED light control [182]. Among four light spectra (100% red, 100% green, 100% blue, and an R:G:B ratio of 1:1:1) tested, flaxseed (Linum usitatissimum) microgreens treated with 100% blue light exhibited the highest content of flavonoids (2.48 mg catechin equivalents [CAE] g −1 FW), total phenols (3.76 mg GAE g −1 FW), chlorogenic acid (1.10 mg g −1 FW), and antioxidant capacity (8.06 µmol Trolox equivalent antioxidant capacity [TEAC] g −1 FW) [103].…”