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Oxidation of Tryptophan by H 2 O 2 in Model Systems
Author(s) -
KELL GISELA,
STEINHART HANS
Publication year - 1990
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1990.tb01613.x
Subject(s) - tryptophan , chemistry , degradation (telecommunications) , aqueous solution , ring (chemistry) , radical , stereochemistry , medicinal chemistry , organic chemistry , amino acid , biochemistry , telecommunications , computer science
Degradation reactions of tryptophan (trp) and the dipeptides alanyltryptophan (ala‐trp) and phenylalanyltryptophan (phe‐trp), induced by H 2 O 2 , were investigated under different conditions in aqueous systems. Decreases in the content of trp as well as the formation of soluble degradation products were determined. Highest losses of trp were obtained after H 2 O 2 treatment at 100°C for 2 hr at pH 8.5. Lowest losses occurred at pH 4.0, 25°C, for 30 min. The destruction of trp in ala‐trp was similar, while losses of trp in phe‐trp under the same reaction conditions were lower. This was indicative of a negative induction effect of the phenyl ring. The quantity of degradation products showed extensive variations, dependent upon the radical mechanism of the oxidation reaction.