Effect of Fortification with Iron on Susceptibility of Skim Milk and Nonfat Dry Milk to Oxidation

Iron-fortified nonfat dry-milk can be made by mixing with dry ferric ammonium citrate or by spray drying ironfortified skim milk concentrates (45% total solids). Concentrates can be fortified directly with an aqueous solution of ferric chloride or ferric ammonium citrate (any convenient concentration) or ema be prepared from skim milks fortified similarly before pasteurization, Although some skim milks are susceptible to iron-catalyzed oxidation, they are stabilized during the concentration which precedes drying, and this resistance is retained in iron-fortified dry milk. Iron salts can be added in arnonnts equivalent to 20 mg iron/liter skiru milk with no adverse flavor effects when iron-fortified dry milk is reconstituted to skim milk or" used in the preparation of 2-10 milk. In other food applications of fortified nonfat dry milk the only adverse effect of added iron was an undesirable color shift when it was added to cocoa, tea, or coffee. In rats, iron in iron-fortified milk is nutritionally as available as that in ferrous sulfate~