Abstract: The growth, bioactive compound contents and antioxidant activity of broccoli sprouts sprayed with exogenous MgSO4 at 0, 25, 50 and 75 mmol/L were studied in this investigation. The results showed that MgSO4 inhibited the growth of broccoli sprouts. The contents of chlorophyll and total phenolics increased with the increase of MgSO4 concentration; however, ascorbic acid content continuously reduced. In addition, 5-day-old sprouts contained more glucosinolates and sulforaphane than 8-day-old sprouts, whereas the opposite was observed for myrosinase activity. MgSO4 treatment significantly enhanced the contents of glucosinolates and sulforaphane as well as myrosinase activity, but no significant difference was found between 50 and 75 mmol/L treatments. Antioxidant ability was significantly promoted by MgSO4 treatment. Specially, no significant difference in 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity was observed between 50 and 75 mmol/L MgSO4 groups. Nevertheless, H2O2 scavenging capacity was gradually enhanced with the increase of MgSO4 concentration. These results suggest that 50 mmol/L MgSO4 treatment could be useful to improve the nutritional value and health-promoting function of broccoli sprouts.

Key words: broccoli sprouts, glucosinolates, sulforaphane, total phenolics, ascorbic acid, antioxidant ability