Introduction

Antioxidants markedly delay or prevent oxidation of the substrate (Halliwell, 1999; Shahidi, 2000), when they are present in foods or in the body at low concentrations compared to that of an oxidizable substrate. Food manufacturers have used food-grade antioxidants, mainly of a phenolic nature, to prevent quality deterioration of products and to maintain their nutritional value. Antioxidants have also been of interest to health professionals because they help the body to protect itself against damage caused by reactive oxygen species (ROS) as well as reactive nitrogen species (RNS) and reactive chlorine species (RCS) associated with degenerative diseases (Figure 8.1).