383: Comparative Effects of Laser-Assisted Germination and Substrate Selection on the Growth and Quality of Broccoli and Radish Microgreens

Introduction

Microgreens are nutrient-dense young plants with increasing demand due to their health benefits and culinary applications. However, optimizing growth conditions to enhance quality while maintaining sustainability is an ongoing challenge. This study investigates the combined effects of laser treatment and various substrates (coco coir, peat, and cotton) on germination, growth metrics, color properties, and bioactive compounds in broccoli and radish microgreens.

Methods

Broccoli and radish microgreens were grown on coco coir, peat, and cotton substrates using seeds with or without laser treatment (450 nm, 85 mW, 1-second on/off, 5 minutes).Growth metrics (germination rate, sprout length, and root length), color properties (L*, a*, b* values), and bioactive compounds (total phenolic content (TPC), DPPH radical scavenging activity, and total flavonoid content (TFC)) were measured.

Results

Laser treatment significantly enhanced germination and growth metrics in both microgreens compared to untreated seeds. Germination rates achieved 100% in coco coir for both species. Sprout and root lengths were notably higher in coco coir-grown, laser-treated samples (e.g., broccoli: 6.2 cm/8.8 cm; radish: 7.2 cm/7.4 cm) compared to untreated controls. TPC, DPPH, and TFC showed significant increases (e.g., broccoli: TPC 344.56 mg/100g, DPPH 172.86 mg/100g, TFC 54.6 mg/100 g; radish: TPC 483.11 mg/100 g, DPPH 213.22 mg/100 g, TFC 72.5 mg/100 g). Peat showed moderate improvement, while cotton exhibited minimal enhancement, highlighting its limited efficacy for bioactive compound synthesis. Additionally, color analysis revealed that laser treatment significantly improved the visual appeal of microgreens. For broccoli microgreens, L* (lightness) increased from 55.1 to 58.8, a* (greenness) improved from -15.2 to -16.5, and b* (yellowness) increased from 18.6 to 20.9 with coco coir. Similarly, radish microgreens showed enhanced brightness, greenness, and vibrancy with laser treatment, confirming superior visual quality. Among the tested substrates, coco coir proved the most effective substrate, outperforming peat (moderate benefits) and cotton (minimal response).

Significance

This study highlights the synergistic benefits of laser treatment and coco coir substrate, yielding maximum germination rates, enhanced growth metrics, improved visual quality, and higher concentrations of bioactive compounds. These findings highlight a sustainable strategy for improving the quality, marketability, and bioactive enrichment of microgreens, providing valuable insights for high-quality production.

Authors: Gulcin Yildiz, Hao Feng