Feb. 22, 2002
Department of Food Science
Initial Ph.D Seminar
Presenter: Seong Jae Yoo
Advisor: Dr. Thomas Hartman
Iron Chelation Peptides: An Alternative Approach to Inhibit IronCatalyzed Lipid Oxidation
Nutrient-fortified foods such as infant formulas are commonly formulated with
higher concentrations of oils, proteins, vitamins and minerals than other food products.
These components are necessary in infant formulas in order to improve nutritional quality
so that Recommended Daily Allowance (RDA) can be met. The high concentrations of
oils and metals often lead to lipid oxidation during processing and storage. Preventative
strategies to reduce this problem such as the use of good quality oil, storage at low
temperature and packaging under vacuum or inert gas have been applied in the infant
formula industry. However, lipid oxidation catalyzed by transition metals (mainly iron)
remains a major concern.
Casein phosphopeptides (CPP) from casein hydrolylsates have been used in the
infant formula industry to improve the bio-availability of calcium in some Asian
countries. CPP is also known to have a strong iron-chelation activity due to a sequence of
phosphoseryl residues. If the iron-chelation activity of CPP can be shown to reduce ironcatalyzed lipid oxidation, this will identify another benefit of using CPP in nutrientfortified foods. We hypothesize that the formation of Fe-CPP chelation complexes would
reduce iron mobility in the food system and the catalytic activity of iron would be
reduced. Consequently, the addition of CPP into foods containing high concentrations of
oil and iron would possibly inhibit the catalytic activity of iron in lipid oxidation.
During a preliminary study, the antioxidative activity of CPP against ironcatalyzed lipid oxidation was determined by the ferrous-thiocyanate method. CPP was
shown to inhibit the generation of hydroperoxides. From this study, we deduce that iron
chelation of CPP is able to reduce the oxidative catalytic activity of iron. Addition of CPP
is an alternative approach to inhibit iron-catalyzed lipid oxidation. Future studies will
include investigations into the antioxidative properties of CPP as a function of the amino
acid sequence (e. g. molecular weight and hydrophobicity of residues).
References:
K.M. Schaich, “Metals and Lipid Oxidation. Contemporary Issues” Lipids, Vol. 37 (3)
209-218, 1992
R. J. FitzGerald, “Potential uses of Caseinophosphopeptides,” Int. Dairy Journal, 8: 451457, 1998
M. T. Satue-Gracia, E. N. Frankel, N. Rangavajhyala, and J. B. German, “Lactoferrin in
Infant Formulas: Effect on Oxidation,” J. Agri. Food Chem. 48: 4984-4990, 2000