Antioxidant activity of plant extracts on the inhibition of citral off-odor formation

Mol Nutr Food Res. 2004 Sep;48(4):308-17. doi: 10.1002/mnfr.200400027.


Grape seed, pomegranate seed, green tea, and black tea extracts were used to inhibit the off-odor from citral degradation. A 0.1 M citrate buffer (pH 3), containing 100 ppm citral and 200 ppm gallic acid equivalent plant extract, was incubated at 40 degrees C. The reaction mixtures were analyzed by high-performance liquid chromatography (HPLC) at days 0, 6, 10, 13, and 16 to monitor degradation of citral and formation of alpha, p-dimethylstyrene, p-cymene-8-ol, and p-methylacetophenone. The addition of plant phenolic extracts could not inhibit citral degradation, however, all four plant extracts significantly inhibited p-methylacetophenone formation. The samples, with the addition of plant extracts, exhibited higher concentrations of alpha, p-dimethylstyrene and p-cymene-8-ol than the control. This is presumed to be due to the oxygen-scavenging effect of plant extracts blocking the pathway from p-cymene-8-ol to p-methylacetophenone. Our results suggest that these plant extracts act as general antioxidants inhibiting the generation ofp-methylacetophenone regardless of the types of water-soluble phenolic compounds existing in the plant extracts.

MeSH terms

  • Acyclic Monoterpenes
  • Antioxidants / pharmacology*
  • Camellia sinensis / chemistry
  • Chromatography, Gas
  • Chromatography, High Pressure Liquid
  • Gas Chromatography-Mass Spectrometry
  • Lythraceae / chemistry
  • Monoterpenes / chemistry*
  • Odorants / prevention & control*
  • Phenols / pharmacology
  • Plant Extracts / chemistry*
  • Plant Extracts / pharmacology*
  • Plant Leaves / chemistry
  • Seeds / chemistry
  • Vitis / chemistry


  • Acyclic Monoterpenes
  • Antioxidants
  • Monoterpenes
  • Phenols
  • Plant Extracts
  • citral