Enhancement of glucosinolate and sulforaphane formation of broccoli sprouts by zinc sulphate via its stress effect

• ZnSO4 raised glucosinolate content of broccoli sprouts.
• ZnSO4 enhanced myrosinase activity and its gene expression of broccoli sprouts.
• ZnSO4 enhanced sulforaphane formation of broccoli sprouts via its stress effect.

Broccoli sprouts have attracted much attention in recent years for their abundant phytochemicals such as glucosinolates and sulforaphane. In this study, zinc sulphate (ZnSO4) as a sulphur (S)-source was compared with potassium sulphate (K2SO4) and methionine (Met), significantly increased glucosinolates content and stimulated sulforaphane formation by enhancing myrosinase activity and gene expressions related to glucoraphanin biosynthesis and sulforaphane formation in broccoli sprouts. However, it resulted in a stress effect on sprout growth. Thus, ZnSO4 is a suitable S-source to improve sulforaphane formation in broccoli sprouts via its stress effect.