On-line HPLC analysis of the antioxidant activity of phenolic compounds in brewed, paper-filtered coffee

Angélique Stalmach, William Mullen, Chifumi Nagai, Alan Crozier

Research output: Contribution to journalArticlepeer-review

104 Citations (Scopus)

Abstract

Caffeoyl-, feruloyl- and dicaffeoylquinic acids (chlorogenic acids) in infusions from green and medium roasted coffee beans were identified and quantified by reverse phase HPLC with photodiode array and MS3 detection prior to assessment of the antioxidant activity using an HPLC system with post-column on-line antioxidant detection based on 2,2′-azinobis-3- ethylbenzothiazoline-6-sulphonic acid radical scavenging activity. Caffeoylquinic acids were the most abundant antioxidants and roasting induced isomerisation with a decline in 5-O-caffeoylquinic acid and concomitant increases in the 3- and 4-O-derivatives. This did not affect the level of caffeoylquinic acid-derived antioxidant activity in the roasted coffee. Roasting did, however, result in the appearance of additional unidentified HPLC peaks with antioxidant activity. Because of this and an increase in the antioxidant activity of components that did not elute from the reversed phase HPLC column, the antioxidant capacity of the beverage derived from medium roast beans was double that of the unroasted coffee. The antioxidant activity of coffees that have undergone different degrees of roasting would, therefore, appear to be due to combinations of different components. The effect of roasting on chlorogenic acids in coffee beans is considered, and the possible contribution of Maillard reaction products to the antioxidant capacity of roasted coffees is discussed.

Original languageEnglish
Pages (from-to)253-262
Number of pages10
JournalBrazilian Journal of Plant Physiology
Volume18
Issue number1
DOIs
Publication statusPublished - 2006

Keywords

  • ABTS
  • Chlorogenic acids
  • Coffea
  • HPLC-MS
  • Hydroxycinnamates

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