Lysinoalanine: Production, significance and control in preparation and use of soya and other food proteins

  • B. J. Struthers
Soya Protein—Nutrition—Roundtable Discussions

Abstract

Formation of lysinoalanine (LAL) in proteins in response to alkali treatment is a well-known phenomenon. The quantity of LAL formed depends on temperature, the time of exposure to alkali, the type of protein, the concentration of protein and alkali in some instances, and probably the type of cation in the alkaline solution. Higher temperatures, longer exposure times, and higher pH’s generally result in more LAL formation. The addition of mercaptoethanol or cysteine to an alkaline protein solution decreases LAL formation markedly; lanthionine is apparently a major product formed when cysteine is added to an alkaline protein solution. Some LAL is likely to be formed in any protein-containing product that is subjected to alkaline treatment, and has been shown to be formed in some protein products under extreme heat conditions. Proper control of temperature and pH in processing can reduce or eliminate LAL formation. LAL has not been shown to present a toxicological hazard to any species other than the rat. Its presence in large quantities in any protein indicates destruction of cysteine and lysine; the nutritional inferiority of severely alkali- or heat-treated proteins due to LAL formation, amino acid degradation and isomerization, Maillard product formation, and so on is well documented. The small quantities of dietary LAL in food products currently on the market seem to represent no health hazard; the reduced nutritional quality of protein products that contain relatively high levels of LAL should be considered when these products are major sources of dietary protein.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Walsh, R.G., A.S. Nashef and R.E. Feeney, Int. J. Peptide Protein Res. 14:290 (1979).CrossRefGoogle Scholar
  2. 2.
    Bohak, Z. J. Biol. Chem. 239:2878 (1964).Google Scholar
  3. 3.
    DeGroot, A.P., P. Slump, L. Van Beek and V.J. Feron, in “Evaluation of Protein for Humans,” edited by C.E. Bodwell, AVI, Westport, 1977, pp. 270–283.Google Scholar
  4. 4.
    DeRham, O., P. Van de Revaart, E. Bujard, F. Mottu and J. Hidalgo, Cereal Chem. 54:238 (1977).Google Scholar
  5. 5.
    Hasegawa, K., and N. Okamoto, Agric. Biol. Chem. 44:649 (1980).Google Scholar
  6. 6.
    Provansal, M.M.P., J.-L.A. Cuq and J.-C. Cheftel, J. Agric. Food Chem. 23:938 (1975).CrossRefGoogle Scholar
  7. 7.
    Hayashi, R., and I. Kameda, Agric. Biol. Chem. 44:175 (1980).Google Scholar
  8. 8.
    Karayiannis, N.I., J.T. MacGregor and L.F. Bjeldanes, Food Cosmet. Toxicol. 17:585 (1979).CrossRefGoogle Scholar
  9. 9.
    Creamer, L.K., and A.R. Matheson, J. Dairy Sci. Technol., N. 2, 12:253 (1977).Google Scholar
  10. 10.
    Sternberg, M.M., C.Y. Kim and F.J. Schwende, Science 190:992 (1975).CrossRefGoogle Scholar
  11. 11.
    Aymard, C., J.-L. Cuq and J.-C. Cheftel, Food Chem. 3:1 (1978).CrossRefGoogle Scholar
  12. 12.
    Struthers, B.J., R.R. Dahlgren, D.T. Hopkins and M.L. Raymond, in “Soy Protein and Human Nutrition,” edited by H. Wilcke, D.T. Hopkins and D.H. Waggle, 1979, pp. 235–260.Google Scholar
  13. 13.
    Raymond, M.L., J. Food Sci. 45:56 (1980).CrossRefGoogle Scholar
  14. 14.
    Finley, J.W., J.T. Snow, P.H. Johnston and M. Friedman, Adv. Exp. Biol. Med. 86 B:85 (1977).Google Scholar
  15. 15.
    Chu, N.T., P.L. Pellett and W.W. Nawar, Agric. Food Chem. 24: 1084 (1976).CrossRefGoogle Scholar
  16. 16.
    Sanderson, J., J.S. Wall, G.L. Donaldson and J.F. Cavins, Cereal Chem. 55:204 (1978).Google Scholar
  17. 17.
    Karayiannis, N.I., J.T. MacGregor and L.F. Bjeldanes. Food Cosmet. Toxicol. 17:591 (1979).CrossRefGoogle Scholar
  18. 18.
    Struthers, B.J., R.R. Dahlgren and D.T. Hopkins, J. Nutr. 107:1190 (1977).Google Scholar
  19. 19.
    DeGroot, A.P., P. Slump, V.J. Feron and L. Van Beek. Ibid. 106:1527 (1976).Google Scholar
  20. 20.
    Van Beek, L., V.J. Feron and A.P. DeGroot, Ibid. 104:1630 (1974).Google Scholar
  21. 21.
    Struthers, B.J., D.T. Hopkins, E.E. Prescher and R.R. Dahlgren, Ibid. 108:954 (1978).Google Scholar

Copyright information

© American Oil Chemists’ Society 1981

Authors and Affiliations

  • B. J. Struthers
    • 1
  1. 1.Ralston Purina CompanySt. Louis

Personalised recommendations