The stability of isothiocyanates in broccoli extract: Oxidation from erucin to sulforaphane was discovered

The health-beneficial effects of Brassica vegetables are attributed to glucosinolates-derived isothiocyanates (ITCs) whose yield is always underestimated due to their reactivity and volatility. In this work, the distribution and stability of four ITCs, including allyl ITC (AITC), phenethyl ITC (PEITC), erucin (ERN), and sulforaphane (SFN), incorporated in water and broccoli extract were described. All ITCs were mainly distributed in the aqueous phase (> 99 %). AITC and PEITC exhibited similar stability in water and broccoli extract. However, an oxidation of ERN to SFN was observed in the broccoli extract, so a rapid decrease in ERN was observed while SFN experienced an increase before the decline. Except for ERN, all three ITCs become more labile when the pH increases from 3.4 to 8.4. Both oxygen and acid conditions promote the oxidation of ERN. Those results contribute to a better understanding of the stability and detection of ITCs in broccoli extract.