Stability and Shelf Life of Bioactive Compounds during Food Processing and Storage: Soy Isoflavones

ABSTRACT: During the past several years, the nutrition community has recognized the importance of the nonnutritive components of plant foods. These nonnutritive components are commonly called phytochemicals. One of the most exciting developments in the phytochemicals field is the beneficial biological activity of isoflavones from soy. Benefits include the potential reduced cancer risk, cholesterol homeostasis, and other hormone replacement therapy treatments. Yet, very little attention has been given to the interactions of bioactive phytochemicals with other food ingredients. Various studies demonstrated the loss of soy isoflavones during storage and the effect of processing conditions on specific modifications of soy isoflavones. Beyond apparent 1st-order degradation kinetics, there is a change in the isoflavones profile according to processing and storage conditions. This change in chemical structure is very likely to affect the bioavailability and bioactivity of soy isoflavones. Understanding the reactions that affect soy isoflavones bioactivity will provide a basis for developing food with the beneficial quality of isoflavones. This article presents current information on the stability of soy isoflavones and highlights how these changes may affect their bioavailability and biological activity. Most importantly, the aim of this article is to point out the fact that much more data are required to fully understand the chemistry and the kinetics of isoflavones reaction in model systems and food.