Oxygen dependency of one-electron reactions generating ascorbate radicals and hydrogen peroxide from ascorbic acid

William L. Boatright

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

The effect of oxygen on the two separate one-electron reactions involved in the oxidation of ascorbic acid was investigated. The rate of ascorbate radical (Asc-) formation (and stability) was strongly dependent on the presence of oxygen. A product of ascorbic acid oxidation was measurable levels of hydrogen peroxide, as high as 32.5 μM from 100 μM ascorbic acid. Evidence for a feedback mechanism where hydrogen peroxide generated during the oxidation of ascorbic acid accelerates further oxidation of ascorbic acid is also presented. The second one-electron oxidation reaction of ascorbic acid leading to the disappearance of Asc- was also strongly inhibited in samples flushed with argon. In the range of 0.05-1.2 mM ascorbic acid, maximum levels of measurable hydrogen peroxide were achieved with an initial concentration of 0.2 mM ascorbic acid. Hydrogen peroxide generation was greatly diminished at ascorbic acid levels of 0.8 mM or above.

Original languageEnglish
Pages (from-to)1361-1367
Number of pages7
JournalFood Chemistry
Volume196
DOIs
StatePublished - Apr 1 2016

Bibliographical note

Publisher Copyright:
© 2015 Elsevier Ltd.

Keywords

  • Ascorbate radical
  • Ascorbic acid
  • Ascorbyl radical
  • Dehydroascorbate
  • Hydrogen peroxide

ASJC Scopus subject areas

  • Analytical Chemistry
  • Food Science

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