Melatonin immersion affects the quality of fresh‐cut broccoli ( Brassica oleracea L.) during cold storage: Focus on the antioxidant system

In the current study, fresh‐cut broccoli was soaked in melatonin solution before cold storage (4°C, 95% RH) for 25 days. The results indicated that 100 µM melatonin treatment inhibited the increase of L * and b * values and retained higher hue angle, total chlorophyll content, and fresh weight during storage. Furthermore, 100 µM melatonin treatment obviously increased antioxidant contents including ascorbic acid, total phenols, and flavonoids, and enhanced the antioxidant activity of florets. Individual phenolic compounds including epicatechin, rutin, and quercetin were positively influenced by melatonin treatment. Superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) activities were obviously enhanced by 100 µM melatonin treatment whereas peroxidase (POD) activity was significantly reduced. Moreover, florets treated with melatonin exhibited lower malondialdehyde (MDA), H 2 O 2 , and O 2 − levels. Our research concluded that melatonin treatment could be an effective technique for enhancing antioxidant capacity and improving the quality of fresh‐cut broccoli during cold storage. Practical applications Fresh‐cut fruits and vegetables are more prone to senescence than their intact forms during postharvest storage. Broccoli is a healthy vegetable and has high demands in many countries. In order to reduce economic losses, it is important to delay the senescence and maintain the quality of fresh‐cut broccoli during postharvest storage. In this article, 100 µM melatonin treatment was found to significantly enhance antioxidant capacity and delay the senescence of fresh‐cut broccoli florets, which maintained the quality of broccoli during cold storage. We believe that melatonin treatment can be applied for the preservation of more fresh‐cut fruits and vegetables.