ABSTRACT
Introduction ........................................................................................................ 343
Fundamental Principles .................................................................................... 344
Two Polarizing Food Stability Theories Have Overshadowed True
Complexities................................................................................................... 347
Diffusion and Reaction...................................................................................... 349
Observations on Rates of Diffusion and Reaction........................................ 350
Observations on the Influence of Matrix Mobility on Reaction Rate ....... 353
Correlations of T
to Chemical and Physical Processes .............................. 356
The Presence of Charged Solutes .................................................................... 364
Conclusions......................................................................................................... 365
References ........................................................................................................... 368
Water is highly important in foods as both an environmental variable and an
ingredient. Changes in the water content of foods can be accompanied by
drastic changes in the nature of food texture, microbial growth, flavor, color,
and other properties. This dynamic nature of food systems can be modeled
just as any chemical reaction by the principles of thermodynamics and
reaction kinetics. Today, this field within food science is struggling with the
increasing complexity that predictive models are developing. Food physical
chemists once thought that the simple concept of water activity (a
) would
provide all of the predictive power one would need to ensure food quality.
However, the anomalies of a
