Water activity in liquid food systems: A molecular scale interpretation

Andrew J. Maneffa, Richard Stenner, Avtar S. Matharu, James H. Clark, Nobuyuki Matubayasi, Seishi Shimizu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Water activity has historically been and continues to be recognised as a key concept in the area of food science. Despite its ubiquitous utilisation, it still appears as though there is confusion concerning its molecular basis, even within simple, single component solutions. Here, by close examination of the well-known Norrish equation and subsequent application of a rigorous statistical theory, we are able to shed light on such an origin. Our findings highlight the importance of solute-solute interactions thus questioning traditional, empirically based “free water” and “water structure” hypotheses. Conversely, they support the theory of “solute hydration and clustering” which advocates the interplay of solute-solute and solute-water interactions but crucially, they do so in a manner which is free of any estimations and approximations.

Original languageEnglish
Pages (from-to)1133-1138
Number of pages6
JournalFood Chemistry
Early online date9 Jun 2017
Publication statusPublished - 15 Dec 2017

Bibliographical note

© 2017 The Authors. Published by Elsevier Ltd.


  • Kirkwood-Buff theory
  • Polyol
  • Statistical thermodynamics
  • Sugar
  • Water activity
  • Water structure

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