Pre-harvest application of proline, methionine, and melatonin improves shelf-life and maintains nutritional quality of Brassica oleracea florets during cold storage

Abstract

The reduction in shelf-life and nutritional value of cauliflower florets are the most vital problems during cold storage. This research was performed to explore the impact of the pre-harvest foliar implementation of proline (PR), methionine (MT), and melatonin (ML), at a rate of 25 mg.L−1, on shelf-life and active composites of cauliflower florets (cv. ‘Arasya’) stored at 10 °C for 14 d. The obtained results exhibited that florets from treated plants with PR, MT, and ML were lower in water loss, electrolyte leakage, browning index, and titratable acidity (TA) compared with untreated plants, at the end of storage. Furthermore, these pre-harvest treatments significantly slow down the loss of total sugar content, reducing sugar, total soluble solid (TSS), glucosinolates concentration (Gly), total phenols (TP), vitamin C (VC), and antioxidant activity (DPPH) than control samples. After 14 days of storage, the application of PR, MT, and ML significantly improved the activity levels of phenylalanine ammonia-lyase (PAL), and catalase (CAT) as well as declined the polyphenol oxidase (PPO), peroxidase (POD) activates in the florets during the cold storage. Therefore, the pre-harvest application of PR, MT, and ML might be promising substances to keep the nutritional quality of cauliflower forests and reduce the browning index during cold storage.