Effects of CaCl2 on the metabolism of glucosinolates and the formation of isothiocyanates as well as the antioxidant capacity of broccoli sprouts

The effects of CaCl2 on metabolism of glucosinolates (GLs) and formation of isothiocyanates (ITCs), as well as the antioxidant capacity of broccoli sprouts, were investigated. The results showed that CaCl2 treatment enhanced BrST5b (sulfotransferase 5b) and limited AOP2 (2-oxoglutarate-dependent dioxygenase 2) expression, which increased GLs biosynthesis. CaCl2 also promoted the gene expression of myrosinase (MYR) and its activity, and thus increased ITCs formation. Three ITCs and two nitriles were found in the hydrolysate of broccoli sprouts. CaCl2 treatment increased the content of 1-isothiocyanato butane significantly. Then, CaCl2 increased the formation of ITCs by regulating gene expression and enzyme activity. After CaCl2 treatment, the antioxidant capacity of sprouts increased and the formed ITCs mainly contributed to total antioxidant capacity and DPPH• scavenging capacity.