EFFECTS OF SUPPLEMENTAL IRON AND COPPER ON LIPID OXIDATION IN MILK .1. COMPARISON OF METAL-COMPLEXES IN EMULSIFIED AND HOMOGENIZED MILK

Because of its wide consumption in the United States, cow milk is a good vehicle for delivering supplemental iron and copper to prevent anemia in infants, children, and adolescents, but transition metals may cause “oxidized” flavors and odors in dairy products. To help predict oxidative deterioration that may occur in commercially fortified milks and to complement organoleptic evaluations we describe the use of the thiobarbituric acid (TBA) test to quantitate lipid peroxidation due to iron and copper. Various chemical forms of iron and copper complexes-ionic, chelated, and polynuclear-are compared with respect to their ability to promote lipid peroxidation during short-term incubation and long-term cold storage in raw and pasteurized milk. Emulsification of milk fat prior to fortification greatly reduced lipid peroxidation by all metal complexes. Compared under any conditions to the simple ferrous and cupric salts, the iron(III) and copper(II) chelates of nitrilotriacetate and lactobionate produced significantly less lipid peroxidation at concentrations within the practical range of fortification. © 1979, American Chemical Society. All rights reserved.