Characterization of benzyl isothiocyanate extracted from mashed green papaya by distillation

•Benzyl isothiocyanate (BITC) can be extracted from green papaya by distillation.•The degradation of BITC in aqueous solution was prevented by frozen storage.•The addition of l-cysteine effectively prevented BITC from decomposition.•This evidence might be useful for the preparation of BITC with lower toxicity. The aim of this study was to extract benzyl isothiocyanate (BITC) from green papaya by distillation apparatus without using organic solvents, and to improve the stability of BITC in aqueous solution. The distillation of mashed green papaya successfully yielded BITC as a water solution with more than 80% purity with good reproducibility. The amount of BITC in the distilled water gradually decreased during its storage at 4 °C, whereas it was not significantly changed at −20 °C for a few months. Moreover, the addition of l-cysteine ameliorated the BITC decomposition by the 4 °C-storage, but not affected by N-acetyl-cysteine and glutathione. These results suggested that the combination of BITC extraction by distillation and cysteine supplementation as well as frozen storage might be a useful method for the preparation and storage of the safer grade of BITC-containing extract.