European Food Research and Technology

, Volume 221, Issue 3, pp 434–438

Effect of coffee physical structure on volatile release

Original Paper

DOI: 10.1007/s00217-005-1196-2

Cite this article as:
Anese, M., Manzocco, L. & Maltini, E. Eur Food Res Technol (2005) 221: 434. doi:10.1007/s00217-005-1196-2

Abstract

The mechanisms of volatile release from soluble coffee powders with different roasting degrees were studied. The presence of volatiles in the headspace during coffee humidification was analyzed by gas chromatography. Small amounts of volatiles were observed at low water activities (aw), independently from the roasting degree; as the aw increased headspace volatiles rose and then decreased as the moisture further increased. The changes in aw and volatiles went along with the changes of coffee structure from a free-flowing powder to a sticky viscous fluid. The mechanism of volatiles release was controlled by both kinetic and thermodynamic factors. The former prevailed at low aw in glassy systems; while the latter became important at high aw when, due to increased mobility, equilibrium conditions were approached. Modified state diagrams were used to predict the critical temperature and aw at which structural collapse and volatile release occurred. As far as equilibrium condition was achieved, coffee volatiles were partially re-adsorbed in the liquid phase.

Keywords

Coffee powderVolatile releasePhysical structurePhase transitions

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Dipartimento di Scienze degli AlimentiUniversity of UdineUdineItaly