Metabolomic analysis based on EESI-MS indicate blue LED light promotes aliphatic-glucosinolates biosynthesis in broccoli sprouts

Broccoli sprouts are rich in secondary metabolites, especially glucosinolates (GLs). The synthesis of GLs can be modified by light. In this study, extractive electrospray ionization-mass spectrometry (EESI-MS) was used to analyze the broccoli sprouts extracts (BSE) under different light quality treatments. Multivariable statistical methods were used to analyze the difference of different light quality treatments. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to analyze the gene expression of key enzymes in the aliphatic-GLs biosynthesis pathway. Nineteen compounds, including 7 GLs, 3 phenolic acids, 6 amino acids and 3 organic acids were simultaneously detected in one minute by EESI-MS. Relative expression of MYB28 , BCAT4 , CYP79F1 , CYP83A1 and AOP3 were mostly upregulated in R5B5 (light ratios of red/blue 5:5) treatment. These findings suggest that blue light improving the accumulation of secondary metabolites in broccoli sprouts, and the R5B5 treatment was most beneficial. Furthermore, we established EESI-MS method to simultaneous and rapid detection of secondary metabolites in broccoli sprouts, especially GLs. This study could provide a reference for selecting proper LED lighting conditions to produce broccoli sprouts with high content of bioactive components, and provides light regulation technology and theoretical basis for the industrialized production of sprouts.