Antioxidants are present naturally in virtually all food commodities,
providing them with a valuable degree of protection against oxidative
attack. When food commodities are subjected to processing, such natural
antioxidants are often depleted, whether physically, from the nature of
the process itself, or by chemical degradation. In conse- quence,
processed food products usually keep less well than do the commodities
from which they originated. Ideally, food producers would like them to
keep better. This objective can often be achieved by blending natural
products rich in antioxidants with processed foods, or by using well
recognised antioxidants as food additives. In order to understand their
action, and hence to apply antioxidants intelligently in food product
formulation, some knowledge of the mechanisms by which they function is
necessary. This is complex and of antioxidative may rely on one or more
of several alternative forms intervention. Accordingly, the various
mechanisms that may be relevant are discussed in Chapter 1, in each case
including the 'intervention' mechanism. When present in, or added to,
foods antioxidants are functional in very small quantities, typically,
perhaps, at levels of 0-01 % or less.