Abstract
The grain of some varieties of sorghum contains 2% or more condensed tannin; many other varieties contain no tannin at all. Agronomic advantages, e.g., resistance to bird depredation, are associated with high-tannin sorghums, which have relatively low nutritional value for nonruminants. The biological effects of tannin are a result of its propensity for binding proteins; both hydrogen bonding and hydrophobic interactions are involved. Sorghum tannins can bind dietary proteins and reduce their digestibility. Purified digestive enzymes are inhibited by tannin, but significant inhibition in vivo is unlikely. Proteins differ greatly in their affinity for tannin. Those with highest affinity are large, have an open structure, contain no bound carbohydrate and are rich in proline. Sorghum proteins of the alcohol-soluble prolamine fraction associate strongly with tannin, are difficult to remove during tannin purification and are found combined with tannin in the indigestible residue after in vitro digestion with pepsin. On germination, the seed may sacrifice a portion of these proteins to bind the tannin that might otherwise interfere with metabolism by inhibiting seed enzymes. During seed development, tannin molecules are relatively short and do not effectively precipitate proteins; as the seed dries, tannins undergo polymerization to an average of ca. 6 flavan-3-ol units/molecule. The antinutritional effects of sorghum tannins can be eliminated by soaking the grain in dilute aqueous alkali, but not by cooking. When rats are put on high-tannin sorghum diets, their parotid glands undergo hypertrophy and produce a group of unique salivary proteins with extremely high affinity for tannin. These proteins contain over 40% proline and are devoid of sulfur-containing and aromatic amino acids. This metabolic adaption may protect rats against tannin by binding and inactivating it immediately when it enters the digestive tract.
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References
Haslam, E., in The Biochemistry of plants, Vol. 7, edited by P.K. Stumpf and E.E. Conn, Academic Press, New York, 1981, p. 527.
McManus, J.P., K.G. Davis, T.H. Lilley and E. Haslam, J. Chem. Soc. Chem. Comm., 309 (1981).
Price, M.L., A.M. Stromberg and L.G. Butler, J. Agric. Food Chem. 27:1270 (1979).
Hagerman, A.E., and L.G. Butler, Ibid. 28:944 (1980).
Neucere, N.J., and G. Sumrell, Ibid. 28:19 (1980).
Price, M.L., and L.G. Butler, Bulletin No. 272 of the Agricultural Experiment Station, Purdue University, West Lafayette, Indiana 47907 (1980).
Bruggers, R.L., and M.M. Jaeger, Sorghum in the Eighties: Proceedings of the International Symposium on Sorghum, 2–7 Nov., 1981, ICRISAT, Patancheru, A.P., India, 1982, p. 303.
Harris, H.B., Proceedings of the 24th Annual Corn and Sorghum Research Conference 24:113 (1969).
Harris, H.B., and R.E. Burns, Agronomy J. 65:957 (1973).
Harris, H.B., and R.E. Burns, Ibid. 62:835 (1970).
Sells, D.R., Ph.D. Thesis, Purdue University, West Lafayette, IN, 1983.
Gustavson, K.H., J. Polymer Science 12:317 (1954).
Oh, H.I., J.E. Hoff, G.S. Armstrong and L.A. Haff, J. Agric. Food Chem. 28:394 (1980).
Meek, K.M., and J.B. Weiss, Biochem. Biophys. Acta 587:112 (1979).
Leatham, G.F., V. King and M.A. Stahmann, Phytopathology 70:1134 (1980).
Hagerman, A.E., and L.G. Butler, J. Agric. Food Chem. 26:809 (1978).
Hagerman, A.E., Ph.D. Thesis, Purdue University, West Lafayette, IN, 1983.
Hagerman, A.E., and L.G. Butler, J. Agric. Food Chem. 28:947 (1980).
Hagerman, A.E., and L.G. Butler, J. Biol. Chem. 256:4494 (1981).
Aoki, K., R. Shinke and H. Nishira, Agric. Biol. Chem. 45:121 (1981).
Oh, H.I., and J.E. Hoff, J. Food Science 44:87 (1979).
Haslam, E., Biochem. J. 139:285 (1974).
Armstrong, G., M.S. Thesis, Purdue University, West Lafayette, IN, 1976.
Watanabe, T., T. Mori, T. Tosa and I. Chibata, Agric. Biol. Chem. 45:1001 (1981).
Watanabe, T., T. Mori, T. Tosa and I. Chibata, J. Chromatog. 207:13 (1981).
Ramachandran, G.N., and C. Ramakrishnan, in Biochemistry of Collagen, edited by G.N. Ramachandran and A.H. Reddi, Plenum Press, NY, 1976, p. 45.
Strumeyer, D.R., and M.J. Malin, Biochem. J. 118:899 (1970).
Jambunathan, R., and E.T. Mertz, J. Agric. Food Chem. 21:692 (1973).
Fishman, M.L., and N.J. Neucere, J. Agric. Food Chem. 28:477 (1980).
Rostagno, H.W., W.R. Featherston and J.C. Rogler, Poultry Science 52:765 (1973).
Nelson, T.S., E.L. Stephenson, A. Burgos, J. Floyd and J.O. York, Ibid. 54:1620 (1975).
Cousins, B.W., T.D. Tanksley, Jr., D.A. Knabe and T. Zebrowska, J. Animal Science 53:1524 (1981).
Knabe, D.A., Proc. of the Sorghum Food Quality Workshop, CIMMYT, El Batan, Mexico, April 13–17, 1982, p. 52.
Schaffert, R.E., V.L. Lechtenberg, D.L. Oswalt, J.D. Axtell, R.C. Pickett and C.L. Rhykerd, Crop Science 14:640 (1974).
Chibber, B.A.-K., E.T. Mertz and J.D. Axtell, J. Agric. Food Chem. 28:160 (1980).
Hahn, D.H., J.M. Faubion, S.H. Ring, C.A. Doherty and L.W. Rooney, Cereal Chem. 59:132 (1982).
Griffiths, D.W., and G. Mosely, J. Science Food Agric. 31:255 (1980).
Armstrong, G., Ph.D. Thesis, Purdue University, West Lafayette, IN, 1976.
Henneke, C.M., and R.T. Wedding, Arch. Biochem. Biophys. 168:443 (1975).
Bhat, C.S., and T. Ramasarma, Biochem. J. 181:143 (1979).
Kelly, S.J., D.E. Dardinger and L.G. Butler, Biochemistry 14:4983 (1975).
Price, M.L., A.E. Hagerman and L.G. Butler, Nutrition Reports International 21:761 (1980).
Mehansho, H., A.E. Hagerman, L.S. Clements, L.G. Butler, J. Rogler and D.M. Carlson, Proc. Natl. Acad. Science U.S., 80:3948 (1983).
Watterson, J.J., and L.G. Butler, J. Agric. Food Chem. 31:41 (1983).
Blakely, M.E., L.W. Rooney, R.D. Sullins and F.R. Miller, Crop Science 19:837 (1979).
Morrall, P., N. v. d. W. Liebenberg and C.W. Glennie, Scanning Electron Microscopy 3:571 (1981).
Oberthur, E., R.L. Nicholson and L.G. Butler, J. Agric. Food Chem. 31:660 (1983).
Butler, L.G., Ibid. 30:1090 (1982).
Daiber, K.H., J. Science Food and Agric. 26:1399 (1975).
Watson, T.G., and L. Novellie, Agrochemophysica 8:61 (1976).
Price, M.L., L.G. Butler, J.C. Rogler and W.R. Featherston, J. Agric. Food Chem. 27:441 (1979).
Armstrong, W.D., J.C. Rogler and W.R. Featherston, Poultry Science 53:714 (1974).
Muindi, P.J., S. Thomke and R. Ekman, J. Sci. Food Agric. 32:25 (1981).
Chavan, J.K., S.S. Kadam, C.P. Ghonsikar and D.K. Salunkhe, J. Food Sci. 44:1319 (1979).
McGrath, R.M., W.Z. Kaluza, K.H. Daiber, W.B. van der Riet and C.W. Glennie, J. Agric. Food Chem. 30:450 (1982).
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Butler, L.G., Riedl, D.J., Lebryk, D.G. et al. Interaction of proteins with sorghum tannin: Mechanism, specificity and significance. J Am Oil Chem Soc 61, 916–920 (1984). https://doi.org/10.1007/BF02542166
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DOI: https://doi.org/10.1007/BF02542166