Melatonin treatment enhances flavonol content and antioxidant capacity in bell peppers (Capsicum annuum L.) during postharvest storage

Postharvest oxidative stress accelerates senescence and flavonol loss in bell peppers, reducing nutritional quality and shelf life, while the role of exogenous melatonin in preserving specific flavonols and regulating the AsA-GSH cycle during ambient storage remains unclear. This study evaluated the effects of melatonin (100 and 200 mu mol/L) on flavonol composition, antioxidant capacity, and antioxidant defence systems in bell peppers stored for nine days at 23 +/- 2 degrees C. Melatonin significantly preserved major flavonols, particularly quercetin, luteolin, and apigenin derivatives, with 200 mu mol/L providing the greatest retention. Antioxidant capacity measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ABTS (-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays and activities of catalase, peroxidase, and ascorbate peroxidase were markedly enhanced by melatonin treatment. The AsA-GSH cycle was positively regulated, especially at 100 mu mol/L, maintaining higher levels of reduced antioxidants. After 9 days, ascorbic acid contents were 5.24 and 6.60 mg g-1 in peppers treated with 100 and 200 mu mol/L melatonin, respectively, compared with 4.40 mg g-1 in controls. Glutathione (GSH) levels were higher in treated samples (10.59-10.64 mg g-1) than in controls (9.22 mg g-1), while oxidised GSH accumulation was significantly suppressed. Overall, exogenous melatonin mitigates oxidative stress and preserves flavonols, supporting its postharvest application in bell peppers during storage.

Dergi

INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY

Yıl

2026

Cilt

61

Sayı

1

ISSN

0950-5423

eISSN

1365-2621

DOI

10.1093/ijfood/vvag043

WoS UID

WOS:001729487600001