Analysis of glucosinolates and their breakdown products from Mul-kimchis using UPLC-MS/MS

This study aimed to analyze glucosinolates and their breakdown products in three types of traditional cold vegetable soups kimchi known as Mul-kimchis (Dongchimi, DC; Yeolmu Mul-kimchi, YK; Nabak kimchi, NK) using UPLC-ESI-MS/MS. Glucosinolates and their breakdown products in the ethanolic extract from Mul-kimchis were analyzed via UPLC-ESI-MS/MS MRM mode, and the developed analysis method underwent validation for parameters including linearity, LOD, LOQ, accuracy, and precision. As a result, six glucosinolates (glucoraphanin, glucoraphenin, glucoerucin, glucoraphasatin, glucobrassicin, and 4-methoxyglucobrassicin; 4MGB) were detected in the DC extract. In contrast, the YK extract contained only two glucosinolates (glucoraphasatin and 4MGB), while the NK extract contained only one glucosinolate (4MGB). Among the glucosinolates, glucoraphasatin was the highest in the DC extract (21.1 +/- 2.8 mg/100 g dry basis), while 4MGB dominated in Mul-kimchis overall, with the highest concentration found in DC (11.6 +/- 2.1 mg/100 g). Regarding the breakdown products, indole-3-carboxaldehyde (I3CA), sulforaphane, and ascorbigen were detected in the extracts from both YK and NK. However, only I3CA and ascorbigen were detected in the extract from DC. Notably, ascorbigen exhibited significantly higher concentrations (p < 0.05) among the breakdown products in Mul-kimchis, with the highest levels observed in the YK extract (4.47 +/- 0.26 mg/100 g).