Reducing yellowing and enhancing antioxidant capacity of broccoli in storage by sucrose treatment

• 12 g L−1 sucrose extended the shelf life of broccoli florets.
• Sucrose inhibited the decrease of total glucosinolate and sulforaphane contents at 20 °C.
• Sucrose improved antioxidant activity and maintained quality of broccoli at 20 °C.

The effect of sucrose treatment on shelf life, the color, contents of glucosinolate, sulforaphane, total phenols, and antioxidant activity in broccoli florets was investigated. The results showed that sucrose (12 g L−1) treatment extended shelf life, inhibited the increase of L* value, retained a high hue angle and chlorophyll content. The decreases of glucosinolate and sulforaphane contents in broccoli florets were suppressed after sucrose treatment. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), phenylalanine ammonia-lyase (PAL) and catalase (CAT) were enhanced in sucrose-treated florets, whereas the activity of peroxidase (POD) was significantly reduced. Sucrose treatment also enhanced total phenolic content and maintained higher levels of total and reducing sugars. These results indicated that sucrose treatment can prolong shelf life in non-refrigerated retail display cases, maintain quality and improve the nutritional value of postharvest broccoli florets.