This manual explains water activity in foods and shows why commonly held ideas about free and bound water are often inaccurate. It demonstrates how moisture sorption isotherms are created and how they are used to solve real-world problems such as the change in rate of moisture gain for individual packaged products over time, or the amount of sugar needed to lower the water activity of a product to make it shelf stable.

The authors emphasize the physical chemistry of water in biological systems. For every equation provided they furnish examples from practical experience. These examples will help food scientists understand thermodynamics (equilibrium processes and water activity), dynamics (rate processes such as mass transfer of moisture between ingredients), and structure (weeping, swelling, droplets, and edible barriers). Using this manual will help solve product development problems and improve the quality of the foods brought to the market.

Moisture Sorption: Practical Aspects of Isotherm Measurement and Use, Second Edition

Water Activity

Moisture Sorption Isotherms

Determination of Moisture Sorption Isotherms

Using Moisture Sorption Isotherms: Food Stability

Using Moisture Sorption Isotherms: Moisture Transfer

Using Moisture Sorption Isotherms: Humectant Selection