Characterization of sinapyl derivatives in pineapple (Ananas comosus [L.] Merill) juice

Three previously unidentified phenolic compounds were found in pineapple (A nanas comosus [L.] Merill)juice in substantial concentrations and were isol ated by semipreparative reverse phase HPLC. The structures were elucidated from UV spectra, acid hydrolysis, and subsequent amino acid analysis, mass spectrometry, and two-dimensional NMR spectroscopy. The compounds are ident ified as S-sinapyl-L-cysteine, N-L-gamma-glutamyl-S-sinapyl-L-cysteine, and S-sinapylglutathione.