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Dose‐dependent utilisation of casein‐linked lysinoalanine, N (epsilon)‐fructoselysine and N (epsilon)‐carboxymethyllysine in rats
Author(s) -
Somoza Veronika,
Wenzel Elisabeth,
Weiß Carola,
ClawinRädecker Ingrid,
Grübel Nadine,
Erbersdobler Helmut F.
Publication year - 2006
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.200600021
Subject(s) - maillard reaction , casein , chemistry , urine , lysine , excretion , endogeny , food science , in vivo , amino acid , biochemistry , biology , microbiology and biotechnology
During the heat treatment of protein‐containing foods, the amino acid lysine is most prone to undergo chemical reactions in the course of amino acid cross‐linking or Maillard reactions. Among the reaction products formed, lysinoalanine (LAL), N (epsilon)‐fructoselysine (FL) and N (epsilon)‐carboxymethyllysine (CML) are those which serve as sensitive markers for the heat treatment applied. From a nutritional perspective, these compounds are ingested with the diet in considerable amounts but information about their metabolic transit and putative in vivo effects is scarce. In the present study, casein‐linked LAL, FL and CML were administered to rats in two different doses for 10 days. Quantitation of LAL, FL and CML in plasma, tissue and faeces samples revealed that the kidneys are the predominant sites of accumulation and excretion. The maximum percent of dietary LAL, FL and CML excreted in the urine was 5.6, 5.2 and 29%, whereas the respective recoveries in the kidneys were 0.02, 26 and 1.4%. The plasma and tissue analyses revealed that the endogenous load of either compound is increased by its dietary intake. But the dose‐dependent utilisation of dietary protein‐linked LAL, FL and CML in rats has been demonstrated for the first time to vary substantially from each other.