Influence of water activity on food product quality and stability

Abstract

Although maximum stability of natural products has been tied to minimum total moisture, research in the last 25 years has defined a narrow optimum activity range for many natural foods. Water activity has a closer relationship to the chemical, physical, and biological properties of foods than moisture content; it may have a direct effect on chemical and enzymatic reactions and on microorganism proliferation. Fairly narrow activity ranges may cause changes in texture, color, flavor, aroma, stability, and acceptability of both processed and raw food products. Most applied work in this field has been pioneered by water activists who have used their own tools and methods. Preparation of moisture sorption isotherms will be facilitated by development of automatic, precise, rapid, and convenient techniques to determine activity and absolute moisture content