Effect of holder pasteurisation on total concentrations and iron-binding profiles of holo -lactoferrin used as fortifier in donor human milk

Lactoferrin is a multifunctional protein and one of the most abundant proteins in human milk. Holder pasteurisation, commonly applied in human milk banks, can reduce the levels of this iron-binding protein. However, there are no studies available about the effects of Holder pasteurisation on holo-lactoferrin (iron-bound form). In this study, we synthesised a isotopically labelled iron-lactoferrin complex [57Fe(III)2-Lf] and used it to fortify donor milk samples, which were submitted to pasteurisation. The total contents of lactoferrin and iron-lactoferrin complex were determined by ELISA and elemental speciation was performed by size exclusion chromatography coupled to inductively coupled plasma mass spectrometry. The results showed that the levels of lactoferrin was reduced 61 ± 11% after pasteurisation. Nevertheless, the decrease was significantly lower in the samples spiked with 57Fe(III)2-Lf, suggesting that the binding with iron could protect lactoferrin from the effects of the heat during pasteurisation.