Journal of the American Oil Chemists Society

, Volume 27, Issue 8, pp 317–321

The tannin and related pigments in the red skins (Testa) of peanut kernels


  • Mack F. Stansbury
    • Southern Regional Research Laboratory
  • Elsie T. Field
    • Southern Regional Research Laboratory
  • John D. Guthrie
    • Southern Regional Research Laboratory

DOI: 10.1007/BF02649320

Cite this article as:
Stansbury, M.F., Field, E.T. & Guthrie, J.D. J Am Oil Chem Soc (1950) 27: 317. doi:10.1007/BF02649320


The red skins of peanut kernels contain a catecholtype tannin. The purified tannin represented about 7% of the weight of the skins. Much smaller quantities of phlobaphene and so-called “leuco-anthocyanic chromogen” were isolated from the skins. Some evidence of the presence of traces of a flavonic-type pigment was obtained.

Spectrophotometric investigations of the isolated tannin, phlobaphene, and “leuco-anthocyanic chromogen” indicated a close relationship of the three pigments.

The tannin gave a water-soluble red pigment when refluxed with alcoholic hydrochloric acid. This pigment exhibited certain properties which are indicative of an oxonium-type structure.

The elementary analyses and certain properties of the isolated tannin and related pigments were considerably different from those reported by previous investigators. The amorphous nature of these substances makes chemical investigation difficult.

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© The American Oil Chemists' Society 1950