Improved metabolomic approach for evaluation of phytochemicals in mustard, kale, and broccoli microgreens under different controlled environmental agriculture conditions

Authors: LI, YANFANG - University Of Maryland; Zhou, Bin; TENG, ZI - University Of Maryland; ZHANG, MENGLIANG - Middle Tennessee State University; YU, LIANGLI - University Of Maryland; Luo, Yaguang - Sunny; Chen, Pei; Sun, Jianghao

Submitted to: Journal of Agriculture and Food Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2023
Publication Date: 7/22/2023
Citation: Li, Y., Zhou, B., Teng, Z., Zhang, M., Yu, L., Luo, Y., Chen, P., Sun, J. 2023. Improved metabolomic approach for evaluation of phytochemicals in mustard, kale, and broccoli microgreens under different controlled environmental agriculture conditions. Journal of Agriculture and Food Research. 14: 100719. https://doi.org/10.1016/j.jafr.2023.100719.
DOI: https://doi.org/10.1016/j.jafr.2023.100719

Interpretive Summary: Controlled environment agriculture (CEA) is an unconventional strategy to increase the concentrations of bioactive compounds in fresh produce by modulating the growing conditions. A rapid and simple investigation method is critical for optimizing CEA conditions to shorten the assessment cycle, save energy and increase the profits of CEA industries. A fast and easy evaluation method for investigation of phytochemical profiles of plants grown under different CEA conditions was developed in this study by using Brassica microgreens as model plants. With this method, a minimum sample size as two cotyledons and UHPLC-HRMS were used for sample analysis. An image-based data normalization coupled with chemometrics-based strategies including principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were applied for the post-acquisition data analysis. This method successfully distinguished between Brassica microgreens grown under different CEA settings in a shortened cycle. The method will be beneficial for the fast and simple evaluation of CEA conditions for different plants.

Technical Abstract: The fast-growing field of controlled environment agriculture (CEA) offers unprecedented opportunities for targeted improvement in concentrations of bioactive compounds in fresh produce achieved through precise modulation of production conditions. To gain full sight of the phytochemical profiles of vegetables grown under different conditions, a rapid analytical strategy is needed for the evaluation of different CEA growing conditions. In this study, Brassica microgreens including ruby streaks mustard (B. juncea), red kale (B. oleracea), and broccoli (B. oleracea) were used as model plants for the evaluation of CEA conditions. Analysis of two first leaves (cotyledons) in microgreens with minimum sample extraction and ultra-high performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) based metabolomic approach was applied for phytochemical analysis. An image-based normalization method using leaf area coupled with chemometrics-based strategies including principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were performed for the post-acquisition data analysis. The method successfully distinguished between Brassica microgreens grown under different CEA settings in a shortened cycle with less organic solvent and labor, which is more environmentally friendly and sustainable. Marker compounds that are responsible for differentiating the Brassica microgreens under various CEA conditions were tentatively identified. The results from the present study may serve as a scientific foundation for the rapid and simple assessment to optimize CEA conditions.