Page 375 - Natural Antioxidants, Applications in Foods of Animal Origin

354 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir - Phosphates: Polyphosphates like sodium tri-polyphosphate are

excellent metal chelators and inhibitors against lipid oxidation.
However, when added to raw meat, they are ineffective due to rapid
hydrolysis to monophosphate by endogenous phosphatase enzyme
(Lee et al., 1998). But when this enzyme is denaturized (e.g., in
cooked meat) polyphosphates inhibited lipid oxidation (Sato &
Hegarty, 1971).
- EDTA: EDTA can inhibit lipid oxidation by forming an inactive
complex with metals.
- Citric acid: Citrate esters improve oil solubility but at least two free
carboxyl groups are needed for effective metal inactivation (Rich-
ards, 2006).
- Desferrioxamine: Desferrioxamine is often used as a metal
chelator, but this can lead to errant results since desferrioxamine
can also act as a free radical scavenger (Kanner & Harel, 1987;
Richards, 2006).
- Peptides: Both carnosine and anserine are endogenous antioxida-
tive dipeptides found in skeletal muscle at high concentrations
(Lynch & Kerry, 2000). They are known to be the most abundant
antioxidants in meats. It is capable of chelating copper, scavenging
peroxyl radicals, and forming adducts with aldehydes (Decker et al.,
2000). Histidine was found to inhibit non-enzymatic iron mediated
lipid oxidation apparently due to formation of an inactive chelate
but histidine was also found to activate enzymatic pathways of lipid
oxidation (Erickson & Hulin, 1992). In addition, carnosine, anserine,
histidine, lysine, albumin, and sulfur or amine containing compounds
have the ability to bind aldehydes and therefore decrease rancidity in
foods (Decker, 1998).

9.3 ANTIOXIDANTS

The use of molecules with antioxidant activity is the best solution for
preventing oxidative processes during storage and increasing the shelf life
of foods. Several molecules from different sources have been recognized
possessing this ability and used as antioxidants in foods, acting through
one or more of the mechanisms already described. We will comment the
most relevant compounds having this property, their characteristics, and
performances.