Microgreens of Brassicaceae: Genetic diversity of phytochemical concentrations and antioxidant capacities

Authors: XIAO, ZHENLEI - University Of Maryland; Rausch, Steven - Steve; Luo, Yaguang - Sunny; Sun, Jianghao; YU, LU - University Of Maryland; WANG, QIN - University Of Maryland; Chen, Pei; YU, LIANGLI - University Of Maryland; Stommel, John

Submitted to: LWT - Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/24/2018
Publication Date: 10/25/2018
Citation: Xiao, Z., Rausch, S.R., Luo, Y., Sun, J., Yu, L., Wang, Q., Chen, P., Yu, L., Stommel, J.R. 2018. Microgreens of Brassicaceae: Genetic diversity of phytochemical concentrations and antioxidant capacities. LWT - Food Science and Technology. 101:731-737.

Interpretive Summary: Brassica vegetables are known to contain relatively high concentrations of health promoting bioactive compounds and phytonutrients. However, specific nutritional profiles of microgreens from different Brassica species and varieties are lacking. Therefore, the scientists at the USDA-ARS undertook a major study that analyzed the concentrations of bioactive compounds and phytonutrients of 30 commercial varieties of microgreens across different Brassica species. Distinct genotypic variations were observed with significantly higher vitamins C, E and K in microgreens grown from cauliflower, red radish, and rapini seeds while the highest levels of carotenoids were found in microgreens grown from upland cress seeds. These findings contribute significant scientific information to food composition databases, and will be of use to nutrition professionals in the selection of nutrient-dense vegetables for balanced diet recommendations.

Technical Abstract: The market for microgreens has experienced rapid growth in recent years. Microgreens not only provide vivid colors, intense flavors and attractive appeal to dishes, but are also rich in vitamins, carotenoids and other phytochemicals. Brassica vegetables are known to contain relatively high concentrations of bioactive compounds associated with human health. In this study, phytochemicals such as ascorbic acid, tocopherols, phylloquinone, carotenoids, total glucosinolates, total phenolics and antioxidant capacity were determined in 30 different varieties of microgreens in the family Brassicaceae. Among 30 varieties of microgreens, distinct genotypic variations were observed for ascorbic acid (32.9 to 120.8 mg/100 g FW), a-tocopherol (1.6 to 4.1 mg/100 g FW), phylloquinone (1.6 to 3.7 µg/g FW), ß-carotene (4.6 to 10.8 mg/100 g FW), lutein/zeaxanthin (0.8 to 6.3 mg/100 g FW), total glucosinolates (1.0 to 535.5 µmol/100 g FW), total phenolics (88.6 to 811.2 mg GAE/100 g FW) as well as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (157.3 to 806.3 µmol TE/100 g FW). The highest amounts of vitamins C, E and K were found in cauliflower, red radish, and rapini, respectively. The highest levels of carotenoids (including both lutein/zeaxanthin and ß-carotene) were recorded in upland cress microgreens. Komatsuna red microgreens were determined to contain the highest total glucosinolate content; while the greatest total phenolic content and DPPH radical scavenging activity were both recorded in radish ruby microgreens. Results indicated that the Brassicaceae microgreens are good sources of antioxidant phytochemicals, and that there is substantial and significant variation within and between species. The Brassicaceae microgreen nutrient data presented in this study will be of use to nutrition professionals in the selection of nutrient-dense vegetables for balanced diet recommendations.