CaCl₂-HCl electrolyzed water affects glucosinolate metabolism and improves the quality of broccoli sprouts

This study evaluated the effects of CaCl₂-HCl electrolyzed water (CHEW) with different calcium chloride concentrations on broccoli sprouts. CHEW treatment reduced the malondialdehyde (MDA) and H₂O₂ contents of broccoli sprouts. The results showed that 10 kinds of glucosinolates were detected, and glucoraphanin was the dominant component. After hydrolysis, three kinds of isothiocyanates and two kinds of nitriles were detected in broccoli sprouts; however, the corresponding nitrile 4-isothiocyanato-1-butene was not detectable. The sulforaphane content of broccoli sprouts in the 10CHEW (Electrolyte of 10 mM CaCl₂ acidic solution) treatment increased by 34.4%, and the content of sulforaphane nitrile decreased by 53.3% compared with that of the tap water treatment. CHEW changed the metabolism of glucosinolates in broccoli sprouts by promoting the synthesis of glucoraphanin, increasing the activity of myrosinase and decreasing the activity of epithiospecifier protein (ESP) for the generation of more bioactive isothiocyanates. In addition, compared to the tap water treatment, the calcium content in broccoli sprouts treated with 25CHEW (Electrolyte of 25 mM CaCl₂ acidic solution) was dramatically enhanced from 15.8 to 49.7 mg/g DW. CHEW can be a useful tool for enhancing the amount of secondary metabolites and calcium content in broccoli sprouts intended for fresh consumption as a functional food.