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

ABSTRACT Postharvest lighting can modify deterioration rates and nutritional profiles of leafy greens during cold storage. This study evaluated the effects of narrow green light‐emitting diode (LED) spectra on spinach quality during 18 days of storage at 4°C and 98% relative humidity. Spinach was stored under green LEDs peaking at 500 or 530 nm, a mixed‐green treatment (500 + 530 nm), or complete darkness. Illumination was applied at 10 µmol m −2 s −1 with a 12 h light–dark cycle. By Day 18, moisture loss was highest in darkness (22.8%) and lowest under 530 nm LEDs (8.3%). Dark storage caused the greatest color change (Δ E = 7.30), whereas LED‐treated samples better maintained color ( p < 0.05). Overall visual quality (OVQ) declined rapidly under darkness, falling below marketability by Day 6, whereas all LED treatments preserved marketability until Day 10, with 530 nm LEDs producing the highest scores. Nutritional responses varied among treatments. Mixed‐green LEDs increased anthocyanin content by 46.9% compared with darkness ( p < 0.05). Total phenolics were higher under 530 nm and mixed‐green LEDs and remained above initial values, although differences were not significant. Mixed‐green LEDs produced the highest flavonoid content. Chlorophyll and carotenoids remained stable across treatments. Pearson correlation confirmed a strong negative relationship between moisture loss and OVQ ( r = −0.735, p < 0.0001). Targeted green LED lighting effectively preserved spinach quality, with 530 nm LEDs best reducing moisture loss and mixed‐green LEDs supporting anthocyanin and flavonoid retention. Practically, low‐intensity green LEDs in commercial display fridges may help maintain appearance, nutritional value, and marketable shelf life.