Optimizing Spinach Shelf Life and Nutritional Quality Using Targeted LED Light Treatments

Area of Science:

• Horticultural science
• Postharvest technology
• Plant physiology

Background:

• Postharvest lighting influences the deterioration rates and nutritional content of leafy greens.
• Cold storage conditions are critical for maintaining the quality of fresh produce.
• Spinach is a nutrient-dense leafy green susceptible to quality degradation during storage.

Purpose of the Study:

• To evaluate the impact of specific green light-emitting diode (LED) spectra on spinach quality during cold storage.
• To determine the optimal green LED wavelength for preserving spinach's visual and nutritional attributes.
• To assess the effect of green LED lighting on moisture loss, color, overall visual quality, and key phytonutrients.

Main Methods:

• Spinach was stored at 4°C and 98% relative humidity for 18 days.
• Treatments included narrow green LEDs (500 nm, 530 nm), mixed-green LEDs (500 + 530 nm), and darkness.
• Illumination was applied at 10 µmol m⁻² s⁻¹ with a 12 h light-dark cycle.

Main Results:

• Spinach stored under 530 nm LEDs exhibited the lowest moisture loss (8.3%) compared to darkness (22.8%).
• LED treatments significantly maintained color and overall visual quality (OVQ) better than darkness, with 530 nm LEDs yielding the highest OVQ.
• Mixed-green LEDs increased anthocyanin content by 46.9% and supported higher flavonoid levels, while chlorophyll and carotenoids remained stable across treatments.

Conclusions:

• Targeted green LED lighting effectively preserves spinach quality, reducing moisture loss and maintaining visual appeal.
• The 530 nm green LED spectrum is most effective in minimizing moisture loss and preserving visual quality.
• Mixed-green LEDs enhance the retention of specific phytonutrients such as anthocyanins and flavonoids, contributing to improved nutritional value.