Water Activity and Plasticization - Food Shelf Life Stability: Chemical, Biochemical, and Microbiological Changes - page 2

1 Water Activity

and Plasticization

Yrjö H. Roos

TABLE OF CONTENTS

Introduction
Water Activity
Water Activity of Foods
Water Sorption
Temperature Dependence of Water Activity and Sorption
Physical State and Water Plasticization
State Transitions
Effects of Water on the Physical State
Water Activity and Physical State
State Diagrams
Physical Stability
Relaxation Times and Mechanical Properties
Viscosity
Stiffness
Stickiness, Caking, and Collapse
Crispness
Crystallization Phenomena
Chemical and Microbial Stability
Temperature Dependence of Reaction Rates and Quality Changes
Effects of Water and Glass Transition on Reaction Rates
Nonenzymic Browning
Other Reactions
Effects of Structural Transformations on Stability
Collapse
Crystallization of Food Components
Biochemical Stability
Microbial Stability
Control of Stability by Water Activity and Composition
Stability Maps
Future Research
References