Biosynthetic origin of geosmin in red beets (Beta vulgaris L.)

J Agric Food Chem. 2003 Feb 12;51(4):1026-9. doi: 10.1021/jf020905r.


Geosmin provides the characteristic but sometimes undesirable "earthy" flavor to red table beets. To date, it is not known whether geosmin is a byproduct of beet metabolism or synthesized by soil-borne microorganisms and taken up by the beets during maturation. Analysis of mature beet roots revealed that peels contained 6 times the amount of geosmin compared to the bodies and cores. Sterilized beet seeds were aseptically grown in a basal medium prior to analysis for the presence of geosmin. Using a headspace solid-phase microextraction (HSPME) method, the relative recovery of geosmin from beet seedling extracts was 72.0 +/- 4.2% with (-)-menthone as the internal standard. The presence of geosmin in aseptically grown beet seedlings was confirmed by gas chromatography-mass spectrometry using authentic geosmin as the standard. During aseptic growth, the concentration of geosmin in seedlings remained constant for up to 5 months but increased at 6 months. Geosmin added to the growth medium was not absorbed by the seedlings. These studies support the conclusion that red beets are capable of endogenous synthesis of geosmin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Beta vulgaris / chemistry
  • Beta vulgaris / metabolism*
  • Gas Chromatography-Mass Spectrometry
  • Naphthols / analysis*
  • Naphthols / metabolism*
  • Plant Extracts / chemistry
  • Seedlings / chemistry
  • Seedlings / metabolism*


  • Naphthols
  • Plant Extracts
  • geosmin