Somoza Veronika, Wenzel Elisabeth, Weiss Carola, Clawin-Rädecker Ingrid, Grübel Nadine, Erbersdobler Helmut F
German Research Centre for Food Chemistry, Garching, Germany.
Mol Nutr Food Res. 2006 Sep;50(9):833-41. doi: 10.1002/mnfr.200600021.
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.
在对含蛋白质食物进行热处理的过程中，氨基酸赖氨酸在氨基酸交联或美拉德反应过程中最容易发生化学反应。在所形成的反应产物中，赖氨酰丙氨酸（LAL）、N-ε-果糖赖氨酸（FL）和N-ε-羧甲基赖氨酸（CML）是可作为所应用热处理敏感标志物的物质。从营养角度来看，这些化合物会随着饮食大量摄入，但关于它们的代谢过程及假定的体内效应的信息却很少。在本研究中，将与酪蛋白相连的LAL、FL和CML以两种不同剂量给予大鼠，持续10天。对血浆、组织和粪便样本中的LAL、FL和CML进行定量分析发现，肾脏是积累和排泄的主要部位。尿中排泄的膳食LAL、FL和CML的最大百分比分别为5.6%、5.2%和29%，而在肾脏中的相应回收率分别为0.02%、26%和1.4%。血浆和组织分析表明，每种化合物的内源性负荷会因其膳食摄入量而增加。但首次证明，大鼠对与膳食蛋白质相连的LAL、FL和CML的剂量依赖性利用情况彼此差异很大。
