Stability of Tryptophan in Peptides Against Oxidation and Irradiation

  • H. Steinhart
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 294)


Tryptophan (trp) is an essential amino acid for humans and most animals. It is, however, not the first and second limiting essential amino acid, but about 30% of the plant proteins used for human nutrition show a deficiency of trp. Besides cysteine, methionine and lysine, it belongs to the most reactive amino acids, which are endangered especially during food manufacturing processes. Friedman and Cuq (1988) recently reviewed the transformations of trp in foods. They report a lack of information of data concerning the stability of trp against industrial or home processing. Processing techniques, however, can cause losses in the trp content of food. Oxidations are of high significance. The most important reason for the instability of trp, especially against oxidizing agents and irradiation, is the bulky nonpolar aromatic side chain.


Degradation Product Essential Amino Acid Aliphatic Amino Acid Amber Vial Neighboring Amino Acid 
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  1. Friedman, M., and Cuq, J. C., 1988, Chemistry, analysis, nutritional value, and toxicology of tryptophan in food. A review, J. Agric. Food Chem., 36: 1079–1093.CrossRefGoogle Scholar
  2. Howard, J.A. 1973, Homogeneous liquid-phase autoxidations, in: “Free Radicals, Part II”, Kochi, J.K., ed., Wiley, New York, pp. 3–62.Google Scholar
  3. Kanner, J. D., and Fennema, O., 1987, Photooxidation of tryptophan in the presence of riboflavin, J. Agric. Food Chem., 35: 71–76.CrossRefGoogle Scholar
  4. Kell, G., 1988, Ph.D. Thesis, University of Hamburg.Google Scholar
  5. Lin, Y., Means, G. E., and Feeney, R.E., 1969, The action of proteolytic enzymes on N, N-dimethyl proteins, J. Biol. Chem., 244: 789–793.PubMedGoogle Scholar
  6. Lucas, B., and Sotelo, A., 1980, Effects of different alkalies, temperature and hydrolysis times on tryptophan determination of pure proteins and of food, Anal. Biochem., 109: 192–197.PubMedCrossRefGoogle Scholar
  7. Simic, M.G., 1978, Radiation chemistry of amino acids and peptides in aqueous solutions, J. Agric. Food Chem., 26: 6–14.PubMedCrossRefGoogle Scholar
  8. Steinhart, H., 1978, Eine direkte fluorimetris ehe Bestimmungsmethode für Tryptophan aus Nahrungs-und Futtermittelhydrolysäten, Z. Tierphysiol. Tierernähr. Futtermittelkde., 41: 48–56.CrossRefGoogle Scholar
  9. Troeder, U., 1988, Ph.D. Thesis, University of Hamburg.Google Scholar
  10. Vangala, R. R., and Menden, E., 1970, Vergleich verschiedener Methoden zur Bestimmung von Tryptophan in Proteinen, Z. Lebensmitt. Forsch., 142: 195–204.CrossRefGoogle Scholar
  11. Yokote, Y., Arai, K. M., and Akahane, K., 1986, Recovery of tryptophan from 25 minute acid hydrolysates of protein, Anal. Biochem., 152: 245–249.PubMedCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1991

Authors and Affiliations

  • H. Steinhart
    • 1
  1. 1.Institute of Biochemistry and Food ChemistryUniversity of HamburgHamburgGermany

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