摘要：Fortification of foods with iron is a common vehicle for delivering iron in required quantities to the consumer. However, many technological problems occur when food products are fortified with minerals, due mainly to the many reactions of minerals with other food components, e.g. fat oxidation. In the present study, the binding of iron (ferrous sulphate) to common milk protein products, sodium caseinate, whey protein isolate (WPI) and milk protein concentrate (MPC), to form protein-iron complexes was characterized by the amount of iron binding and the turbidity as functions of the iron concentration. In an emulsion containing linoleic acid, the oxidation activity of these protein-iron complexes was compared with that of the iron in its free state. The affinities of caseinate and MPC to bind iron were higher than that of WPI. These differences were attributed to the presence of clusters of phosphoserine residues in casein molecules, that are known to bind divalent cations strongly. Lipid oxidation experiments showed that the ability of iron to catalyse lipid oxidation was reduced significantly when iron was bound to protein compared with when it was in its free form. This suggests that the formation of milk protein-iron complexes could be a novel way of incorporating iron into food products with high bioavailability, good flavour and no solubility problems.
关键词：sodium caseinate; whey protein isolate; milk protein concentrate; protein-iron complex; emulsion oxidation; 酪蛋白酸钠; 乳清分离蛋白; 乳清浓缩蛋白; 蛋白-铁复合物; 乳浊液的氧化; caséinate de sodium; isolat de protéines de lactosérum; concentré de protéines laitières; complexe protéine-fer; oxydation dans les émulsions
