Effect of Putrescine on Postharvest Quality, and Phenolic Compounds and Antioxidant Capacity of Broccoli (Brassica oleracea L. cv. Italica) Florets

In this study، effect of exogenous putrescine on maintaining postharvest quality and antioxidant compounds of two broccoli cultivars، ‘General’ and ‘Liberty’ during cool storage were investigated. Broccoli branchlets were treated with 0. 5، 1 and 1. 5 mM Putrescine. Distilled water was used as control. Treated florets were put into polyethylene bag and transferred to storage with 0°C and 90% RH. Weight loss، total chlorophyll، total phenols and catechin and chlorogenic acid were determined after 40 days of cool storage and kept 2 additional days in room temperature. Results showed that 1. 5 mM putrescine treatment prevented weight loss، delayed chlorophyll degradation and senescence and improved florets quality in General and Liberty cultivars. Total phenols and flavenoids content declined at the end of storage and also two additional days in room temperature، but putrescine treatments prevented its significant decreasing. Catechin and chlorogenic acid content decreased in untreated florets was decreased when transferred to room temperature after long-term storage in low temperature; but 1. 5 mM putrescine increased them in both studied cultivars. Overall، application of 1. 5 mM putrescine with preventing chlorophyll degradation and maintaining antioxidant compounds، delayed broccoli florets senescence.