Magnetic field-assisted blanching enhances sulforaphane synthesis in broccoli florets, revealed by UPLC-ESI-QTRAP-MS/MS

Sulforaphane (SF) is generated from glucoraphanin hydrolysis catalyzed by endogenous myrosinase in <i>Brassicaceae</i> vegetables such as broccoli, with blanching critical to maximize SF formation. However, the effect of magnetic field (MF) treatment on glucoraphanin hydrolysis remains unclear. This study investigated MF-assisted blanching of broccoli florets under 0-10 mT, monitoring myrosinase activity and quantifying SF, sulforaphane nitrile (SFN), and precursor glucosinolates using UPLC-ESI-QTRAP-MS/MS. MF-assisted blanching significantly enhanced myrosinase activity and SF formation, with the greatest effect at 1.0 mT, where myrosinase activity increased 3.11-fold and SF content reached 61.14 ± 1.21 μmol/100 g fresh weight, a 1.89-fold increase relative to the control (blanching only). SFN increased but remained at trace levels, reaching 3.10 ± 0.10 μmol/100 g fresh weight at 1.0 mT versus 0.24 ± 0.09 μmol/100 g in the control. Enhanced hydrolysis was supported by residual glucosinolate levels. These findings suggest a promising strategy to improve SF content in broccoli.