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Quantitative analysis of the major γ glutamyl peptides in onion bulbs ( Allium cepa )
Author(s) -
Shaw Martin L,
Lancaster Jane E,
Lane Geoffrey A
Publication year - 1989
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740480408
Subject(s) - allium , chemistry , cultivar , ninhydrin , cysteine , chromatography , hydrolysis , liliaceae , glutathione , quantitative analysis (chemistry) , peptide , biochemistry , horticulture , botany , enzyme , biology , amino acid
Quantitative analysis of the major γ glutamyl peptides present in cultivars of onion ( Allium cepa L) bulbs representing brown, white and red varieties was achieved by ion exchange and electrophoretic separations and by quantitation involving integration of ninhydrin‐developed spots on thin layer chromatography. γ Glutamyl trans‐prop(I)enyl cysteine sulphoxide was found to be the major γ glutamyl peptide in each of the three cultivars at levels between 1.24 and 2.18 mg g −1 fresh weight, followed by S‐2‐carboxypropyl glutathione (0.45‐0.60 mg g −1 fresh weight) and γ glutamyl phenylalanine (0.09‐0.16 mg g −1 fresh weight). Conclusive identification of each of the compounds was achieved by NMR spectroscopy and by GC‐MS of the n‐butyl, trifluoroacetyl derivatives of the hydrolysis products.