Temporal profile of arugula microgreens: growth and nutritional traits for harvest date optimization

BACKGROUND: Microgreens constitute a rapidly emerging food category characterized by elevated concentrations of bioactive compounds; however, the temporal trajectories associated with their morphological development and nutritional enhancement remain insufficiently defined for harvest date standardization. This study investigated the temporal dynamics of morphometric growth, pigment composition, phenolic metabolism, mineral accumulation, and RGB-derived optical signatures in arugula (Eruca sativa L.) microgreens cultivated under LED-based controlled conditions. Daily harvests were conducted over an eight-day period across three production cycles. Quantitative assessments included hypocotyl length, cotyledon expansion, and fresh biomass, alongside quantification of chlorophylls, carotenoids, and total phenolics, as well as mineral profiling. RGB imaging was simultaneously employed to characterize canopy reflectance patterns throughout development. Understanding these dynamics is essential for defining standardized, evidence-based harvest windows for microgreen producers. RESULTS: Morphometric variables exhibited rapid increases, with biomass and cotyledon area approaching developmental stabilization after day 5, while hypocotyl elongation continued until day 8. Chlorophyll concentrations remained stable, whereas carotenoids showed a small temporal decrease. Calcium, magnesium, and manganese contents increased significantly toward the final harvest days, indicating progressive nutritional enrichment. Total phenolic content fluctuated moderately across the harvest period and was positively correlated with chlorophyll content (r = 0.87). CONCLUSION: The temporal profile of arugula microgreen development indicates that the optimal harvest window spans days 5 to 8, depending on whether production priorities emphasize biomass yield, morphological quality, or maximization of nutrient density, reflecting a trade-off between early harvest for optimal morphological and textural quality and later harvest for enhanced mineral and pigment density. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.