Advertisement

European Food Research and Technology

, Volume 214, Issue 2, pp 92–104 | Cite as

From the green bean to the cup of coffee: investigating coffee roasting by on-line monitoring of volatiles

  • Chahan Yeretzian
  • Alfons Jordan
  • Raphael Badoud
  • Werner Lindinger
Original paper

Abstract

Volatile organic compounds (VOCs), emitted from green coffee beans, during coffee roasting and from a cup of coffee, were all analysed by proton-transfer-reaction mass spectrometry. Firstly, the headspace (HS) of green beans was investigated. Alcohols dominate the HS, but aldehydes, hydrocarbons and organic acids were also abundant. Secondly, we roasted coffee under two different conditions and monitored on-line the VOCs emitted during the process. In a first roasting series, a batch of beans was roasted. After an initial drying phase, dominated by evaporation of water and methanol, the HS concentrations of VOCs such as acetic acid, acetaldehyde, pyridine and methylbutanal rapidly increased and went through a maximum at medium roast level. In a second series, just six beans were roasted. We observed sporadic bursts of some volatiles (furans, butanal, 2,3-pentanedione), coinciding with popping sounds. Other VOCs showed smooth time-intensity profiles (pyridine, pyrazine). These experiments gave a real-time insight into the complex processes taking place during roasting. Finally, the HS of coffee extracts, prepared from beans roasted to different roast levels, were analysed. Most VOCs showed a maximum concentration at medium roast level (e.g. pentanedione, furfural, 5-methyl furfural), while others showed a gradual increase (e.g. pyrrol) or decrease (e.g. methanol).

Coffee Aroma Roasting On-line Proton-transfer-reaction mass spectrometry 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  • Chahan Yeretzian
    • 1
  • Alfons Jordan
    • 2
  • Raphael Badoud
    • 1
  • Werner Lindinger
    • 2
  1. 1.Nestlé Research Center, PO Box 44, CH-1000 Lausanne 26, SwitzerlandSwitzerland
  2. 2.Institut für Ionenphysik, Leopold-Franzens-Universität, Technikerstrasse 25, 6020 Innsbruck, AustriaAustria

Personalised recommendations