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EVEC Microgreens
Preharvest Nutrient Deprivation Reconfigures Nitrate, Mineral, and Phytochemical Content of Microgreens
While imparting gastronomic novelty and sensory delight, microgreens also constitute rudimentary leafy greens packed with nutrients and phytochemicals. As
Marios C. Kyriacou, Christophe El‐Nakhel, Georgios A. Soteriou, Giulia Graziani, Angelos C. Kyratzis, Chrystalla Antoniou, Alberto Ritieni, Stefania De Pascale, Youssef Rouphael
Foods · 2021 · https://doi.org/10.3390/foods10061333
Abstract
While imparting gastronomic novelty and sensory delight, microgreens also constitute rudimentary leafy greens packed with nutrients and phytochemicals. As such, they comprise an upcoming class of functional foods. However, apart from bioactive secondary metabolites, microgreens also accumulate antinutritive agents such as nitrate, especially under conducive protected cultivation conditions. The current work examined nutrient deprivation before harvest (DBH), applied by replacing nutrient solution with osmotic water for six and twelve days, as a strategy for reducing microgreen nitrate levels in different species (lettuce, mustard, and rocket). The three species were sown on a peat-based substrate, cultivated in a controlled climate chamber, and harvested 18 days after sowing, when the first two true leaves emerged. DBH impact on major constituents of the secondary metabolome, mineral content, colorimetric, and yield traits was appraised. Nitrate and mineral content were determined through ion chromatography, phenolic composition through UHPLC-Q-Orbitrap HRMS, and carotenoid composition through HPLC-DAD. Nutrient deprivation was effective in reducing nitrate content; however, effective treatment duration differed between species and decline was more precipitous in nitrate hyperaccumulating species such as rocket. Quercetin and kaempferol glycosides were the flavonol glycosides most abundant in brassicaceous microgreens, whereas lettuce microgreens were steeped in caffeoyl quinic acid. DBH interacted with species as it increased the total phenolic content of lettuce, decreased that of rocket, but did not affect mustard. Further research to link changes in phenolic composition to the sensory and in vivo bioactive profile of microgreens is warranted. Notably, brief (≤6 days) DBH can be applied across species with moderate or no impact on the phenolic, carotenoid, and mineral composition of microgreens. Brief DBH applications also have limited impact on microgreens’ yield and colorimetric traits hence on the commercial value of the product. They can therefore be applied for reducing microgreen nitrate levels without significantly impacting key secondary metabolic constituents and their potential bioactive role.
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How to credit this work
Marios C. Kyriacou; Christophe El‐Nakhel; Georgios A. Soteriou; Giulia Graziani; Angelos C. Kyratzis; Chrystalla Antoniou; Alberto Ritieni; Stefania De Pascale; Youssef Rouphael (2021). Preharvest Nutrient Deprivation Reconfigures Nitrate, Mineral, and Phytochemical Content of Microgreens. Foods. https://doi.org/10.3390/foods10061333 Licensed under Creative Commons Attribution 4.0 (https://creativecommons.org/licenses/by/4.0/). Hosted by EVEC Athens (microgreens.org.gr). No changes were made to this article. Provided as-is, without warranties. EVEC Athens is not affiliated with, and this copy is not endorsed by, the authors or the publisher.
Explore this on our site
- How to grow it: Arugula microgreens — growing guide
- How to grow it: Lettuce microgreens — growing guide
- How to grow it: Mustard microgreens — growing guide
- Related reading: Sensory analysis in microgreens why some are spicy others sweet and others taste like fresh grass
- Related reading: Solanaceae lectins and alkaloids the compounds that make some microgreens toxic
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