Universidad de Córdoba BIODISPONIBILIDAD MINERAL DE ...

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casein before its ingestion, which would increase solubility of iron in the
intestine and, because of iron absorption is related to its intestinal solubility (Kim
et al., 1995), this may be the reason for the enhancing effect of casein
hydrolysis on iron bioavailability (Hurrell et al., 1989). It has been observed that
these caseinophosphopeptides have a high capacity to bind tri- and divalent
cations and keep them soluble at intestinal pH (Galdi & Valencia, 1988) and in
particular, 1,25-β-caseinophosphopeptide coming from tryptic hydrolysis of β-
casein contains four out of the five phosphoserine residues present in the native
protein located at positions 15, 17, 18 and 19 so one mole of 1,25-βcaseinophosphopeptide
could bind up to four moles of iron.
Nevertheless, improvement on iron bioavailability by these
caseinophosphopeptides cannot be justified simply by an increase of iron
solubility and absorption; this must be accompanied by an efficient use of iron in
eritropoyesis or a adequate storage in liver in the ferritin form. In this way,
several experiments (Aït-oukhatar et al., 1997; Aït-oukhatar et al., 1999) in irondeficient
rats fed with different iron supplements (ferrous sulphate, iron bound to
intact β-casein, iron bound to hydrolyzed β-casein and iron bound to 1,25-βcaseinophosphopeptide)
have showed that caseinophosphopeptides, and
specially 1,25-β-caseinophosphopeptide produced the best results on
hemoglonin levels and iron storage in tissues.
Some theories point out, as a consequence of the presence of
biologically active peptides issued from milk proteins in plasma (Mahé et al.,
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